[go: up one dir, main page]

WO2021215630A1 - Low-cost austenitic stainless steel having high strength and high formability, and method for manufacturing same - Google Patents

Low-cost austenitic stainless steel having high strength and high formability, and method for manufacturing same Download PDF

Info

Publication number
WO2021215630A1
WO2021215630A1 PCT/KR2021/001345 KR2021001345W WO2021215630A1 WO 2021215630 A1 WO2021215630 A1 WO 2021215630A1 KR 2021001345 W KR2021001345 W KR 2021001345W WO 2021215630 A1 WO2021215630 A1 WO 2021215630A1
Authority
WO
WIPO (PCT)
Prior art keywords
stainless steel
austenitic stainless
strength
low
cold
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/KR2021/001345
Other languages
French (fr)
Korean (ko)
Inventor
송석원
백종수
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Posco Holdings Inc
Original Assignee
Posco Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Posco Co Ltd filed Critical Posco Co Ltd
Priority to EP21793437.1A priority Critical patent/EP4119693A4/en
Priority to CN202180028609.8A priority patent/CN115398022B/en
Priority to US17/918,014 priority patent/US20230142021A1/en
Priority to JP2022564367A priority patent/JP7395769B2/en
Publication of WO2021215630A1 publication Critical patent/WO2021215630A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0236—Cold rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0242—Flattening; Dressing; Flexing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0273—Final recrystallisation annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/001—Austenite

Definitions

  • the present invention relates to austenitic stainless steel and a method for manufacturing the same, and more particularly, to a low-cost austenitic stainless steel having high strength and high formability and a method for manufacturing the same.
  • the trend of the automobile market is changing from the existing automobile industry centered on internal combustion engines to the battery oriented eco-friendly automobile market. That is, the conventional internal combustion engine vehicle market favoring medium or large vehicles is changing to a battery-centered driving engine market favoring small or light vehicles.
  • the structural material that protects the battery protects the battery from external shocks from the risk of safety accidents such as explosions, requires high strength characteristics to take responsibility for the safety of passengers, and has to be light in order not to increase the weight of a small or light vehicle.
  • structural materials that protect batteries but also general structural materials are being made lighter and stronger. Accordingly, it is necessary to develop high-strength, high-molding materials with excellent productivity and excellent stability so that they can be applied throughout the industry.
  • Stainless steel is a material that can be applied throughout the industry due to its excellent corrosion resistance.
  • austenitic stainless steel since the elongation rate is excellent, there is no problem in making a complex shape according to the various needs of customers, and it has the advantage of a beautiful appearance.
  • austenitic stainless steel is inferior in yield strength compared to general carbon steel, and there is an economic problem of using expensive alloying elements. Therefore, it is required to develop stainless steel for structural materials that can secure a high level of yield strength and appropriate tensile strength while maintaining high formability.
  • the alloy component constituting the austenitic stainless steel is expensive compared to most carbon steels.
  • Ni contained in austenitic stainless steel is not only unstable in raw material supply and demand due to extreme fluctuations in material price, but also difficult to secure supply price stability, and at the same time, there is a problem in price competitiveness because the material itself is high. Therefore, it is required to develop a low-cost austenitic stainless steel in which the content of expensive alloying elements such as Ni is reduced as much as possible.
  • the present invention is to provide a low-cost austenitic stainless steel of high strength and high formability.
  • the high-strength, high-molding, low-cost austenitic stainless steel according to an example of the present invention is, by weight, C: more than 0% 0.08% or less, N: 0.2 to 0.25%, Si: 0.8 to 1.5%, Mn: 8.0 to 9.5%, Cr: 15.0 to 16.5%, Ni: more than 0% and 1.0% or less, Cu: 0.8 to 1.8%, the balance Fe and other unavoidable impurities, and the following formula (1) to (4) may be satisfied.
  • C, N, Si, Mn, Cr, Ni, and Cu mean the content (% by weight) of each element.
  • Each high-strength, high-molding, low-cost austenitic stainless steel of the present invention may have a yield strength of 400 MPa or more of the cold-rolled annealed material.
  • Each high-strength, high-molding, low-cost austenitic stainless steel of the present invention may have an elongation of 55% or more of the cold-rolled annealed material.
  • Each high-strength, high-molding, low-cost austenitic stainless steel of the present invention may have a yield strength of 800 MPa or more of the temper rolled material.
  • Each high-strength, high-molding, low-cost austenitic stainless steel of the present invention may have an elongation of 25% or more of the temper rolling material.
  • the method for producing a high-strength, high-molding, low-cost austenitic stainless steel according to an example of the present invention is, by weight, C: more than 0% 0.08% or less, N: 0.2 to 0.25%, Si: 0.8 to 1.5%, Mn: 8.0 to 9.5%, Cr: 15.0 to 16.5%, Ni: more than 0% and 1.0% or less, Cu: 0.8 to 1.8%, balance Fe and other unavoidable impurities, Preparing a slab satisfying the following formulas (1) to (4), preparing a hot-rolled material by hot rolling the slab, and then annealing to prepare a hot-rolled annealed material, cold-rolling the hot-rolled annealed material to cold-rolled It may include the steps of preparing a cold-rolled annealing material by annealing at a temperature of 1050° C. or higher and then performing temper rolling to prepare a temper-rolled material.
  • C, N, Si, Mn, Cr, Ni, and Cu mean the content (% by weight) of each element.
  • the step of temper rolling may be performed at a reduction ratio of 20% or more.
  • the slab may have a reduction in cross section of 50% or more at a high temperature of 800° C. or more.
  • the cold-rolled annealed material which is cold-rolled and then annealed at 1050° C. or higher, exhibits excellent yield strength, and austenitic stainless steel capable of securing sufficient elongation required for molding even after temper rolling to secure additional strength.
  • austenitic stainless steel capable of securing sufficient elongation required for molding even after temper rolling to secure additional strength.
  • the high-strength, high-molding, low-cost austenitic stainless steel according to an embodiment of the present invention is, by weight, C: more than 0% and 0.08% or less, N: 0.2 to 0.25%, Si: 0.8 to 1.5%, Mn: 8.0 to 9.5%, Cr: 15.0 to 16.5%, Ni: more than 0% and 1.0% or less, Cu: 0.8 to 1.8%, the balance Fe and other unavoidable impurities, and the following formulas (1) to (4) may be satisfied.
  • C, N, Si, Mn, Cr, Ni, and Cu mean the content (% by weight) of each element.
  • the high-strength, high-molding, low-cost austenitic stainless steel according to an embodiment of the present invention is, by weight, C: more than 0% and 0.08% or less, N: 0.2 to 0.25%, Si: 0.8 to 1.5%, Mn: 8.0 to 9.5%, Cr: 15.0 to 16.5%, Ni: more than 0% and not more than 1.0%, Cu: 0.8 to 1.8%, balance Fe and other unavoidable impurities.
  • Carbon (C) is an effective element for stabilizing the austenite phase, and may be added to secure the yield strength of the austenitic stainless steel.
  • the content is excessive, cold workability is reduced due to the solid solution strengthening effect, and ductility, toughness, corrosion resistance, etc. may be reduced by inducing grain boundary precipitation of Cr carbide, and welding properties between materials may be deteriorated. Accordingly, the upper limit of the C content in the present invention may be limited to 0.08% by weight.
  • Nitrogen (N) is one of the most important elements in the present invention. Nitrogen is a powerful austenite phase stabilizing element, and is an effective element for improving the corrosion resistance and yield strength of austenitic stainless steels. However, when the content is excessive, defects such as nitrogen pores may occur during production of the cast slab, and cold workability may be deteriorated due to the solid solution strengthening effect. Accordingly, the upper limit of the N content in the present invention may be limited to 0.25% by weight.
  • Si acts as a deoxidizer during the steelmaking process and is an effective element for improving corrosion resistance.
  • Si is an effective element for improving the yield strength of steel among substitution-type elements.
  • Si may be added in an amount of 0.8 wt% or more.
  • Si as a ferrite phase stabilizing element, promotes the formation of delta ( ⁇ ) ferrite in the cast slab when excessively added, thereby reducing hot workability and adversely affecting the ductility and impact properties of the material. Accordingly, the upper limit of the Si content in the present invention may be limited to 1.5% by weight.
  • Manganese (Mn) is an austenite phase stabilizing element added to replace nickel (Ni) in the present invention, and may be added in an amount of 8.0 wt % or more to suppress the formation of processing-induced martensite to improve cold workability.
  • MnS S-based inclusions
  • Mn fumes are generated during the steelmaking process, which accompanies manufacturing risks.
  • the addition of an excessive amount of Mn sharply deteriorates the corrosion resistance of the product. Accordingly, the upper limit of the Mn content in the present invention may be limited to 9.5% by weight.
  • Chromium (Cr) is a ferrite stabilizing element, but is effective in suppressing martensite phase formation, and is a basic element for securing corrosion resistance required for stainless steel, and may be added in an amount of 15.0 wt % or more. However, if the content is excessive, a large amount of delta ( ⁇ ) ferrite in the slab is formed as a ferrite stabilizing element, which may adversely affect hot workability and material properties. Accordingly, the upper limit of the Cr content in the present invention may be limited to 16.5% by weight.
  • Nickel (Ni) is a strong austenite phase stabilizing element, and is added to ensure good hot workability and cold workability. However, since Ni is an expensive element, it causes an increase in raw material cost when added in a large amount. In the present invention, the upper limit of the Ni content may be limited to 1.0% by weight in consideration of both the cost and efficiency of the steel.
  • Copper (Cu) is an austenite phase stabilizing element, and is added to replace nickel (Ni) in the present invention.
  • Cu is an element that improves the corrosion resistance of the steel in a reducing environment, it can be added 0.8% by weight or more.
  • the upper limit of the Cu content may be limited to 1.8% by weight in consideration of the cost, efficiency, and material properties of the steel.
  • the remaining component of the present invention is iron (Fe).
  • Fe iron
  • the impurities are known to any person skilled in the art of a conventional manufacturing process, all details thereof are not specifically mentioned in the present specification.
  • impurities that are unavoidably incorporated include phosphorus (P) and sulfur (S), and the content thereof may include at least one of P: 0.035 wt% or less, S: 0.01 wt% or less, according to an example of the present invention. .
  • Phosphorus (P) is an impurity that is unavoidably contained in steel and is an element that causes intergranular corrosion of steel or inhibits hot workability, so it is preferable to control its content as low as possible.
  • the upper limit of the P content may be limited to 0.035% by weight or less.
  • S is an impurity that is unavoidably contained in steel, and is an element that segregates at grain boundaries of steel and is a major cause of impairing hot workability, so it is preferable to control its content as low as possible.
  • the upper limit of the S content may be limited to 0.01% by weight or less.
  • the alloy composition may be further limited according to the following formulas (1) to (4).
  • the formula (1) regarding the austenite phase fraction was derived to secure excellent elongation of the cold rolled annealed material prepared by cold rolling and then annealing.
  • Mn, Ni, and N mean the content (% by weight) of each element.
  • Equation (1) The lower the value of Equation (1), the lower the fraction of the austenite phase after annealing.
  • the value of Equation (1) is less than 7.5, the austenitic stainless steel contains 5% or more of delta ferrite or the martensitic phase during cold rolling. A phase transformation will occur.
  • the lower limit of the value of Equation (1) may be limited to 7.5 in order to secure a sufficient elongation of the steel material.
  • Equation (2) was derived in consideration of the improvement of the yield strength by the stress field of the steel material in order to secure the high yield strength of the austenitic stainless steel.
  • C, N, Si, Mn, Cr, Ni, and Cu mean the content (% by weight) of each element.
  • Equation (2) As the value of Equation (2) is higher, the stress field between the lattices increases due to the atomic size difference between the alloying elements, and the limit to withstand plastic deformation against external stress increases. When the value of Equation (2) is less than 12, it is difficult to secure the yield strength required in the present invention. Accordingly, in the present invention, the lower limit of the value of Equation (2) may be limited to 12 for high strength characteristics.
  • Equation (3) was derived in consideration of the phase transformation due to deformation of the austenitic stainless steel.
  • C, N, Si, Mn, Cr, Ni, and Cu mean the content (% by weight) of each element.
  • Equation (3) As the value of Equation (3) is higher, the austenite phase is easily transformed into martensite by external stress. Specifically, when the value of Equation (3) exceeds 70, the austenitic stainless steel exhibits abrupt work-induced martensitic transformation behavior with respect to deformation, and non-uniform plastic working occurs. As a result, there is a problem in that the elongation of the austenitic stainless steel is inferior, so the upper limit of the value of Equation (3) may be limited to 70.
  • Equation (4) was derived by considering the dislocation slip behavior of the steel due to the deformation of the austenitic stainless steel.
  • C, N, Si, Mn, Cr, Ni, and Cu mean the content (% by weight) of each element.
  • Equation (4) The lower the value of Equation (4), the more difficult the cross-slip expression of the austenite phase due to external stress.
  • the value of Equation (4) is less than 11, the austenitic stainless steel shows only planar slip behavior with respect to deformation, and the accumulation of dislocations occurs rapidly due to external stress.
  • the elongation of the austenitic stainless steel is inferior, it is difficult to perform temper rolling, and hot rolling defects such as edge cracks occur during hot deformation at high temperature, which may cause a problem of productivity decrease.
  • the lower limit of the value of Equation (4) may be limited to 11.
  • Equation (4) when the value of Equation (4) is increased, there is a problem in that the plasticity non-uniformity increases due to the occurrence of frequent cross-slip, which increases the stress concentration in the weak part of the steel. As the strength of the steel increases, the tendency of such brittleness and plasticity non-uniformity increases, so that in the case of high-strength steel as in the present invention, a decrease in the elongation of the steel is likely to occur. In consideration of this, the upper limit of Equation (4) in the present invention may be limited to 17.
  • the slab having the above-described alloy composition may have a reduction in cross-section of 50% or more at a high temperature of 800° C. or more.
  • the yield strength of the cold-rolled annealed material may be 400 MPa or more.
  • the elongation of the cold-rolled annealing material may be 55% or more.
  • cold-rolled annealing material means a steel material prepared by hot-rolling-annealing-cold rolling-annealing of a slab.
  • the yield strength of the temper rolled material may be 800 MPa or more.
  • the yield strength may be 800 MPa or more, and the elongation may be 25% or more.
  • "passage-rolled material” means a steel material prepared by temper rolling the above-described cold-rolled annealed material.
  • the method for manufacturing high-strength, high-molding, low-cost austenitic stainless steel according to an embodiment of the present invention is, in weight %, C: more than 0% and 0.08% or less, N: 0.2 to 0.25%, Si: 0.8 to 1.5%, Mn: 8.0 to 9.5%, Cr: 15.0 to 16.5%, Ni: more than 0% and 1.0% or less, Cu: 0.8 to 1.8%, the balance Fe and other unavoidable impurities, and the cast steel that satisfies formulas (1) to (4) preparing a hot-rolled material by hot rolling the slab, then annealing to prepare a hot-rolled annealed material, cold rolling the hot-rolled annealed material to prepare a cold-rolled material, and then annealing at a temperature of 1050 ° C. or higher to cold-rolled It may include the step of providing a blunt material and a step of temper rolling to provide a temper rolled material.
  • the cast steel having the above-described alloy composition may be prepared as a hot-rolled material by hot rolling at a temperature of 1000 to 1300 °C, and then annealing at a temperature range of 1000 to 1100 °C to manufacture a hot-rolled annealing material. At this time, the annealing heat treatment may be performed for 10 seconds to 10 minutes.
  • the hot-rolled annealing material may be cold-rolled to prepare a cold-rolled material, and then annealed to produce a cold-rolled annealed material.
  • cold rolling was performed as a method for improving the yield strength of austenitic stainless steel, and then low temperature annealing heat treatment was performed in a low temperature range of 1000° C. or less.
  • Low-temperature annealing heat treatment does not complete recrystallization, but is a method of increasing strength by using the energy accumulated in the steel during cold rolling.
  • the austenitic stainless steel that has been subjected to the low-temperature annealing heat treatment as described above has the disadvantage that not only there is a possibility that the material may appear non-uniform, but also fine pickling occurs in the pickling process, which is a subsequent process, or the surface shape is not beautiful.
  • the hot-rolled annealed material may be cold-rolled to prepare a cold-rolled material, and then annealed at a temperature of 1050° C. or higher to manufacture a cold-rolled annealed material.
  • the annealing heat treatment may be performed for 10 seconds to 10 minutes.
  • excellent elongation can be secured by not performing low-temperature annealing after cold rolling, and yield strength can also be secured at an appropriate level or more through alloy composition design.
  • the cold-rolled annealed material according to an embodiment of the present invention may have a yield strength of 400 MPa or more.
  • the cold-rolled annealed material according to an embodiment of the present invention may have an elongation of 55% or more.
  • the present invention it is possible to secure excellent yield strength through control of alloy composition and subsequent temper rolling even without performing low-temperature annealing after cold rolling.
  • the yield strength of the temper rolled material may be 800 MPa or more.
  • the temper rolling may be performed at a reduction ratio of 20% or more.
  • strength can be increased by using a phenomenon in which high work hardening occurs as an austenite phase transforms into a work-induced martensite phase during cold deformation, or by using dislocation accumulation of steel.
  • high work hardening occurs as an austenite phase transforms into a work-induced martensite phase during cold deformation
  • dislocation accumulation of steel there is a fear that the elongation of the steel material is rapidly reduced.
  • the present invention by designing the alloy composition as described above, it is possible to appropriately control the phase transformation and dislocation behavior of the steel, thereby preventing the elongation of the steel from rapidly decreasing due to the temper rolling.
  • the yield strength of the temper rolled material is 800 MPa or more, and the high strength, high formability and low cost austenitic stainless steel with an elongation of 25% or more and high forming characteristics are simultaneously satisfied.
  • a steel material having an alloy composition shown in Table 1 was prepared as a slab through ingot melting, heated at 1250° C. for 2 hours, and then hot rolled to prepare a hot rolled material. Thereafter, annealing heat treatment was performed at 1100° C. for 90 seconds to prepare a hot-rolled annealed material. Then, cold rolling was performed at a reduction ratio of 70% to prepare a cold rolled material, and then annealed heat treatment was performed at 1100° C. for 10 seconds to prepare a cold rolled annealed material.
  • Table 1 shows the values of Equations (1) to (4) derived by substituting the alloy composition and alloying element content for each Inventive Example and Comparative Example.
  • the yield strength, tensile strength, and elongation of the cold-rolled annealed materials of each invention example and comparative example were measured.
  • the yield strength, tensile strength, and elongation of the temper-rolled material prepared by 20% temper rolling of the cold-rolled annealed material of each invention example and comparative example were measured.
  • Yield strength, tensile strength, and elongation were measured according to ASTM standards, and yield strength (YS), MPa), tensile strength (Tensile Strength (TS), MPa) and elongation (Elongation ( EL), %) are shown in Table 2 below.
  • Yield strength, tensile strength, and elongation were measured according to ASTM standards, and yield strength (YS), MPa), tensile strength (Tensile Strength (TS), MPa) and elongation (Elongation ( EL), %) are shown in Table 2 below.
  • yield strength (YS), MPa), tensile strength (Tensile Strength (TS), MPa) and elongation (Elongation ( EL), %) are shown in Table 2 below.
  • the occurrence of cracks during the 180° adhesion bending test of the annealed material is also described in Table 2 below.
  • the cold-rolled annealed material can secure a yield strength of 400 MPa or more and an elongation of 55% or more.
  • the temper rolling materials of Inventive Examples 1 to 4 have a yield strength of 800 MPa or more and a sufficient elongation of 25% or more even when the temper rolling is performed.
  • Inventive Examples 1 to 4 have a relatively low Ni content of 1.0% by weight or less, thereby securing price competitiveness.
  • Comparative Example 1 was a commercially produced standard austenitic stainless steel, and did not satisfy the composition and formulas (2), (3), and (4) of the present invention, and thus the yield strength was low.
  • the commercial austenitic stainless steel of Comparative Example 1 had a Ni content of 8.1% by weight and was inferior in price competitiveness due to excessive Ni addition compared to the present invention.
  • Comparative Example 2 did not satisfy Equation (1), so the initial delta ferrite remained substantially inside the steel after cold rolling and then annealing. Since the phase interface between the delta ferrite phase and the austenite phase is prone to cracking due to the phase difference during the forming process such as bending of steel, a low value of Equation (1) accompanies cracking during bending. As a result, Comparative Example 2 had a high Si content, so the yield strength was high, and the elongation was also observed, but bending cracks occurred due to the remaining delta ferrite, so that the formability including the bending properties was inferior.
  • Comparative Examples 3 to 5 are steel grades that do not satisfy Formulas (1) to (4) in common. After cold rolling because they do not satisfy Formula (1), a significant portion of the initial delta ferrite remains inside the steel after annealing and bending Formability including properties was inferior, and Equation (2) was not satisfied, resulting in low yield strength. In addition, since the value of Equation (3) was 100 or more, Equation (3) was not satisfied, and plasticity non-uniformity due to the phase transformation to processing induced martensite easily occurred during deformation. In addition, since the value of Equation (4) was low, Equation (4) was not satisfied, and the accumulation of dislocations occurred extremely due to the influence of planar slip. As a result, the elongation was inferior. In particular, Comparative Examples 3 to 5 do not satisfy the formulas (3) and (4), so that the inferior elongation is further lowered after the temper rolling, so that they do not have suitable physical properties for use as a temper rolling material.
  • Comparative Example 6 did not satisfy Equation (1) and was cold-rolled, and then a significant portion of initial delta ferrite remained inside the steel after annealing, resulting in inferior formability including bending properties. In addition, Comparative Example 6 showed a high Si content and excellent yield strength by Equation (2), but did not secure sufficient elongation due to the influence of Equations (3) and (4).
  • Comparative Example 7 did not satisfy Equation (1) and was cold-rolled, and then a significant portion of initial delta ferrite remained inside the steel after annealing, resulting in inferior formability including bending properties. Also, in Comparative Example 7, the value of Equation (3) was 100 or more, which did not satisfy Equation (3), so that plasticity non-uniformity due to the phase transformation into processing-induced martensite easily occurred during deformation. For this reason, the elongation of the cold rolled annealed material and the temper rolled material was inferior.
  • Comparative Example 8 satisfies the composition of alloy elements except Cu and Equations (1) to (4). For this reason, it showed excellent yield strength and elongation when cold-rolled annealed material. However, Comparative Example 8 had poor hot workability due to excessive Cu content. A detailed evaluation thereof will be described later with reference to Table 3 below.
  • Comparative Examples 9 to 10 had excessive hot workability due to excessive Si and Cu contents. A detailed evaluation thereof will be described later with reference to Table 3 below.
  • Comparative Examples 11 and 12 did not satisfy Equation (1), so after cold rolling, a significant portion of initial delta ferrite remained inside the steel after annealing, resulting in inferior formability including bending properties.
  • the value of Equation (4) was excessive, and the plasticity non-uniformity in which the stress concentration in the weak part of the steel increased due to the frequent cross-slip expression was increased. As a result, the elongation of the cold rolled annealed material and the temper rolled material was inferior.
  • the austenitic stainless steel according to the present invention has excellent hot workability, and thus has high productivity and high error rate, and thus has excellent price competitiveness.
  • the reduction of area at each temperature of the slabs of several comparative examples and invention examples having excellent elongation was measured.
  • the reduction in area was measured through a high-temperature tensile test based on ASTM standards, and the results are shown in Table 3.
  • Comparative Example 1 is a commercially produced standard austenitic stainless steel, and exhibits excellent hot workability due to small amounts of Cu and N added to reduce Si or Ni required for the expression of high strength characteristics. However, since such commercial 300 series austenitic stainless steel contains a large amount of expensive Ni element, price competitiveness is quite low. In addition, as evaluated in Table 2, the component composition and formulas (2), (3) and (4) of the present invention were not satisfied, so the yield strength was low.
  • Comparative Examples 2, 6, 9, and 10 an excessive amount of Si was added to improve the yield strength of the cold-rolled annealed material, and Cu was excessively added to replace Ni for price competitiveness. In Comparative Examples 2, 6, 9, and 10, the amount of Si and Cu added was excessive, and thus the hot workability was inferior.
  • Comparative Example 8 the amount of Cu added was excessively outside the range limited by the present invention.
  • the excessively added Cu segregated on the edge or surface of the slab to induce liquid embrittlement, etc., thereby inferior to the hot workability of Comparative Example 8.
  • due to poor hot workability there is a fear that a decrease in the error rate due to edge cracks and an increase in correction cost after hot working occurs, or additional equipment investment for reducing edge cracks may be required.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

The present specification discloses low-cost austenitic stainless steel having high strength and high formability, and a method for manufacturing same. According to an embodiment of the disclosed low-cost austenitic stainless steel having high strength and high formability, the austenitic stainless steel comprises, in weight %, greater than 0% and at most 0.08% of C, 0.2 to 0.25% of N, 0.8 to 1.5% of Si, 8.0 to 9.5% of Mn, 15.0 to 16.5% of Cr, greater than 0% and at most 1.0% of Ni, 0.8 to 1.8% of Cu, and the remainder in Fe and other unavoidable impurities, and satisfies formulas (1) to (4). (1) Ni+0.47Mn+15N ≥ 7.5 (2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12 (3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70 (4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17 Here, C, N, Si, Mn, Cr, Ni, and Cu represent the amounts (weight %) of the respective elements.

Description

고강도, 고성형의 저원가 오스테나이트계 스테인리스강 및 그 제조방법High-strength, high-forming, low-cost austenitic stainless steel and its manufacturing method

본 발명은 오스테나이트계 스테인리스강 및 그 제조방법에 관한 것으로, 보다 상세하게는 고강도, 고성형의 저원가 오스테나이트계 스테인리스강 및 그 제조방법에 관한 것이다. The present invention relates to austenitic stainless steel and a method for manufacturing the same, and more particularly, to a low-cost austenitic stainless steel having high strength and high formability and a method for manufacturing the same.

기존의 내연기관 중심의 자동차 산업에서 배터리 중심의 친환경 자동차 시장으로 자동차 시장의 트렌드가 변화되고 있다. 즉, 종래의 중형 또는 대형차량 선호의 내연기관 자동차 시장은 소형 또는 경량차량 선호의 배터리 중심의 구동기관 시장으로 변화하고 있다. The trend of the automobile market is changing from the existing automobile industry centered on internal combustion engines to the battery oriented eco-friendly automobile market. That is, the conventional internal combustion engine vehicle market favoring medium or large vehicles is changing to a battery-centered driving engine market favoring small or light vehicles.

배터리를 보호하는 구조재는 폭발과 같은 안전사고의 위험으로부터 외부의 충격에서 배터리를 보호하고, 승객의 안전을 책임질 수 있도록 고강도 특성이 요구되며, 소형 또는 경량차량의 무게를 늘리지 않기 위해서 가벼워야 한다. 배터리를 보호하는 구조재 뿐만 아니라 일반적인 구조재용 소재에 있어서도 환경규제에 대응하기 위해 경량화 및 고강도화가 진행 중이다. 이에 따라 산업계 전반에서 적용될 수 있도록 생산성이 우수하며 안정성이 뛰어난 고강도, 고성형의 소재 개발이 필요하다. The structural material that protects the battery protects the battery from external shocks from the risk of safety accidents such as explosions, requires high strength characteristics to take responsibility for the safety of passengers, and has to be light in order not to increase the weight of a small or light vehicle. In order to respond to environmental regulations, not only structural materials that protect batteries but also general structural materials are being made lighter and stronger. Accordingly, it is necessary to develop high-strength, high-molding materials with excellent productivity and excellent stability so that they can be applied throughout the industry.

스테인리스강은 내식성이 우수하여 산업계 전반에 적용될 수 있는 소재이다. 특히, 오스테나이트계 스테인리스강의 경우 연신율이 뛰어나기 때문에 고객의 다양한 요구에 맞춰 복잡한 형상을 만드는데 문제가 없으며, 외관이 미려하다는 장점이 있다. Stainless steel is a material that can be applied throughout the industry due to its excellent corrosion resistance. In particular, in the case of austenitic stainless steel, since the elongation rate is excellent, there is no problem in making a complex shape according to the various needs of customers, and it has the advantage of a beautiful appearance.

그러나, 오스테나이트계 스테인리스강은 일반적인 탄소강에 비해 항복강도가 열위하고, 고가의 합금 원소를 사용하는 경제적인 문제가 있다. 따라서, 고성형 특성을 유지하면서 높은 수준의 항복강도와 적절한 인장강도를 확보 할 수 있는 구조재용 스테인리스강의 개발이 요구된다. However, austenitic stainless steel is inferior in yield strength compared to general carbon steel, and there is an economic problem of using expensive alloying elements. Therefore, it is required to develop stainless steel for structural materials that can secure a high level of yield strength and appropriate tensile strength while maintaining high formability.

또한, 오스테나이트계 스테인리스강을 구성하고 있는 합금성분은 대부분의 탄소강에 비해서 고가라는 문제가 있다. 특히, 오스테나이트계 스테인리스강에 포함되는 Ni은 소재 가격의 극심한 변동에 의해 원료수급이 불안정할 뿐만 아니라 공급가의 안정성 확보가 어려움과 동시에 그 소재가 자체가 높아 가격경쟁력 측면에서 문제가 있다. 따라서, Ni과 같은 고가의 합금원소 함량을 최대한 저감한 저원가 오스테나이트계 스테인리스강의 개발이 요구된다.In addition, there is a problem that the alloy component constituting the austenitic stainless steel is expensive compared to most carbon steels. In particular, Ni contained in austenitic stainless steel is not only unstable in raw material supply and demand due to extreme fluctuations in material price, but also difficult to secure supply price stability, and at the same time, there is a problem in price competitiveness because the material itself is high. Therefore, it is required to develop a low-cost austenitic stainless steel in which the content of expensive alloying elements such as Ni is reduced as much as possible.

상술한 문제점을 해결하기 위하여, 본 발명은 고강도, 고성형의 저원가 오스테나이트계 스테인리스강을 제공하고자 한다.In order to solve the above problems, the present invention is to provide a low-cost austenitic stainless steel of high strength and high formability.

상술한 목적을 달성하기 위한 수단으로서 본 발명의 일 예에 따른 고강도, 고성형의 저원가 오스테나이트계 스테인리스강은 중량%로, C: 0% 초과 0.08% 이하, N: 0.2 내지 0.25%, Si: 0.8 내지 1.5%, Mn: 8.0 내지 9.5%, Cr: 15.0 내지 16.5%, Ni: 0% 초과 1.0% 이하, Cu: 0.8 내지 1.8%, 잔부 Fe 및 기타 불가피한 불순물을 포함하고, 하기 식 (1) 내지 (4)를 만족할 수 있다.As a means for achieving the above object, the high-strength, high-molding, low-cost austenitic stainless steel according to an example of the present invention is, by weight, C: more than 0% 0.08% or less, N: 0.2 to 0.25%, Si: 0.8 to 1.5%, Mn: 8.0 to 9.5%, Cr: 15.0 to 16.5%, Ni: more than 0% and 1.0% or less, Cu: 0.8 to 1.8%, the balance Fe and other unavoidable impurities, and the following formula (1) to (4) may be satisfied.

(1) Ni+0.47Mn+15N ≥ 7.5(1) Ni+0.47Mn+15N ≥ 7.5

(2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12(2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12

(3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70(3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70

(4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17(4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17

여기서, C, N, Si, Mn, Cr, Ni, Cu는 각 원소의 함량(중량%)을 의미한다.Here, C, N, Si, Mn, Cr, Ni, and Cu mean the content (% by weight) of each element.

본 발명의 각 고강도, 고성형의 저원가 오스테나이트계 스테인리스강은 냉연소둔재의 항복강도가 400MPa 이상일 수 있다.Each high-strength, high-molding, low-cost austenitic stainless steel of the present invention may have a yield strength of 400 MPa or more of the cold-rolled annealed material.

본 발명의 각 고강도, 고성형의 저원가 오스테나이트계 스테인리스강은 냉연소둔재의 연신율이 55% 이상일 수 있다. Each high-strength, high-molding, low-cost austenitic stainless steel of the present invention may have an elongation of 55% or more of the cold-rolled annealed material.

본 발명의 각 고강도, 고성형의 저원가 오스테나이트계 스테인리스강은 조질압연재의 항복강도가 800MPa 이상일 수 있다.Each high-strength, high-molding, low-cost austenitic stainless steel of the present invention may have a yield strength of 800 MPa or more of the temper rolled material.

본 발명의 각 고강도, 고성형의 저원가 오스테나이트계 스테인리스강은 조질압연재의 연신율이 25% 이상일 수 있다.Each high-strength, high-molding, low-cost austenitic stainless steel of the present invention may have an elongation of 25% or more of the temper rolling material.

또한, 상술한 목적을 달성하기 위한 다른 수단으로서 본 발명의 일 예에 따른 고강도, 고성형의 저원가 오스테나이트계 스테인리스강의 제조방법은 중량%로, C: 0% 초과 0.08% 이하, N: 0.2 내지 0.25%, Si: 0.8 내지 1.5%, Mn: 8.0 내지 9.5%, Cr: 15.0 내지 16.5%, Ni: 0% 초과 1.0% 이하, Cu: 0.8 내지 1.8%, 잔부 Fe 및 기타 불가피한 불순물을 포함하고, 하기 식 (1) 내지 (4)를 만족하는 주편을 마련하는 단계, 상기 주편을 열간 압연하여 열연재를 마련한 다음, 소둔하여 열연소둔재를 마련하는 단계, 상기 열연소둔재를 냉간 압연하여 냉연재를 마련한 다음, 1050℃ 이상의 온도로 소둔하여 냉연소둔재를 마련하는 단계 및 조질 압연하여 조질압연재를 마련하는 단계를 포함할 수 있다.In addition, as another means for achieving the above object, the method for producing a high-strength, high-molding, low-cost austenitic stainless steel according to an example of the present invention is, by weight, C: more than 0% 0.08% or less, N: 0.2 to 0.25%, Si: 0.8 to 1.5%, Mn: 8.0 to 9.5%, Cr: 15.0 to 16.5%, Ni: more than 0% and 1.0% or less, Cu: 0.8 to 1.8%, balance Fe and other unavoidable impurities, Preparing a slab satisfying the following formulas (1) to (4), preparing a hot-rolled material by hot rolling the slab, and then annealing to prepare a hot-rolled annealed material, cold-rolling the hot-rolled annealed material to cold-rolled It may include the steps of preparing a cold-rolled annealing material by annealing at a temperature of 1050° C. or higher and then performing temper rolling to prepare a temper-rolled material.

(1) Ni+0.47Mn+15N ≥ 7.5(1) Ni+0.47Mn+15N ≥ 7.5

(2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12(2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12

(3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70(3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70

(4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17(4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17

여기서, C, N, Si, Mn, Cr, Ni, Cu는 각 원소의 함량(중량%)을 의미한다.Here, C, N, Si, Mn, Cr, Ni, and Cu mean the content (% by weight) of each element.

본 발명의 각 고강도, 고성형의 저원가 오스테나이트계 스테인리스강의 제조방법에 있어서, 상기 조질 압연하는 단계는 압하율 20% 이상으로 수행할 수 있다.In each of the methods for producing high-strength, high-molding, low-cost austenitic stainless steels of the present invention, the step of temper rolling may be performed at a reduction ratio of 20% or more.

본 발명의 각 고강도, 고성형의 저원가 오스테나이트계 스테인리스강의 제조방법에 있어서, 상기 주편은 800℃ 이상의 고온에서 단면 감소율이 50% 이상일 수 있다.In each high-strength, high-molding, low-cost austenitic stainless steel manufacturing method of the present invention, the slab may have a reduction in cross section of 50% or more at a high temperature of 800° C. or more.

본 발명의 실시예에 따르면 냉간 압연한 다음, 1050℃ 이상으로 소둔한 냉연소둔재가 우수한 항복강도를 나타내며, 추가적인 강도 확보를 위한 조질 압연 이후에도 성형에 필요한 충분한 연신율을 확보할 수 있는 오스테나이트계 스테인리스강을 제공할 수 있다. 또한, 고강도, 고성형 특성을 가지고 있으며, 고가의 합금 원소를 줄였음에도 생산성이 뛰어난 저원가 오스테나이트계 스테인리스강을 제공할 수 있다.According to an embodiment of the present invention, the cold-rolled annealed material, which is cold-rolled and then annealed at 1050° C. or higher, exhibits excellent yield strength, and austenitic stainless steel capable of securing sufficient elongation required for molding even after temper rolling to secure additional strength. can provide In addition, it is possible to provide a low-cost austenitic stainless steel having high strength and high formability, and excellent in productivity even though expensive alloying elements are reduced.

본 발명의 일 예에 따른 고강도, 고성형의 저원가 오스테나이트계 스테인리스강은 중량%로, C: 0% 초과 0.08% 이하, N: 0.2 내지 0.25%, Si: 0.8 내지 1.5%, Mn: 8.0 내지 9.5%, Cr: 15.0 내지 16.5%, Ni: 0% 초과 1.0% 이하, Cu: 0.8 내지 1.8%, 잔부 Fe 및 기타 불가피한 불순물을 포함하고, 하기 식 (1) 내지 (4)를 만족할 수 있다.The high-strength, high-molding, low-cost austenitic stainless steel according to an embodiment of the present invention is, by weight, C: more than 0% and 0.08% or less, N: 0.2 to 0.25%, Si: 0.8 to 1.5%, Mn: 8.0 to 9.5%, Cr: 15.0 to 16.5%, Ni: more than 0% and 1.0% or less, Cu: 0.8 to 1.8%, the balance Fe and other unavoidable impurities, and the following formulas (1) to (4) may be satisfied.

(1) Ni+0.47Mn+15N ≥ 7.5(1) Ni+0.47Mn+15N ≥ 7.5

(2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12(2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12

(3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70(3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70

(4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17(4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17

여기서, C, N, Si, Mn, Cr, Ni, Cu는 각 원소의 함량(중량%)을 의미한다.Here, C, N, Si, Mn, Cr, Ni, and Cu mean the content (% by weight) of each element.

이하에서는 본 발명의 바람직한 실시형태들을 설명한다. 그러나, 본 발명의 실시형태는 여러 가지 다른 형태로 변형될 수 있으며, 본 발명의 기술사상이 이하에서 설명하는 실시형태로 한정되는 것은 아니다. 또한, 본 발명의 실시형태는 당해 기술분야에서 평균적인 지식을 가진 자에게 본 발명을 더욱 완전하게 설명하기 위해서 제공되는 것이다.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes preferred embodiments of the present invention. However, the embodiment of the present invention may be modified in various other forms, and the technical idea of the present invention is not limited to the embodiment described below. Further, the embodiments of the present invention are provided in order to more completely explain the present invention to those of ordinary skill in the art.

본 출원에서 사용하는 용어는 단지 특정한 예시를 설명하기 위하여 사용되는 것이다. 때문에 가령 단수의 표현은 문맥상 명백하게 단수여야만 하는 것이 아닌 한, 복수의 표현을 포함한다. 덧붙여, 본 출원에서 사용되는 "포함하다" 또는 "구비하다" 등의 용어는 명세서 상에 기재된 특징, 단계, 기능, 구성요소 또는 이들을 조합한 것이 존재함을 명확히 지칭하기 위하여 사용되는 것이지, 다른 특징들이나 단계, 기능, 구성요소 또는 이들을 조합한 것의 존재를 예비적으로 배제하고자 사용되는 것이 아님에 유의해야 한다.The terms used in this application are only used to describe specific examples. Therefore, for example, a singular expression includes a plural expression unless the context clearly requires it to be singular. In addition, terms such as "comprises" or "comprises" used in the present application are used to clearly indicate that there is a feature, step, function, component, or a combination thereof described in the specification, and other features It should be noted that it is not intended to preliminarily exclude the existence of elements, steps, functions, components, or combinations thereof.

한편, 다르게 정의되지 않는 한, 본 명세서에서 사용되는 모든 용어들은 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자에 의해 일반적으로 이해되는 것과 동일한 의미를 가진 것으로 보아야 한다. 따라서, 본 명세서에서 명확하게 정의하지 않는 한, 특정 용어가 과도하게 이상적이거나 형식적인 의미로 해석되어서는 안 된다. 가령, 본 명세서에서 단수의 표현은 문맥상 명백하게 예외가 있지 않는 한, 복수의 표현을 포함한다.Meanwhile, unless otherwise defined, all terms used herein should be regarded as having the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Accordingly, unless explicitly defined herein, certain terms should not be construed in an unduly idealistic or formal sense. For example, a singular expression herein includes a plural expression unless the context clearly dictates otherwise.

또한, 본 명세서의 "약", "실질적으로" 등은 언급한 의미에 고유한 제조 및 물질 허용오차가 제시될 때 그 수치에서 또는 그 수치에 근접한 의미로 사용되고, 본 발명의 이해를 돕기 위해 정확하거나 절대적인 수치가 언급된 개시 내용을 비양심적인 침해자가 부당하게 이용하는 것을 방지하기 위해 사용된다.In addition, in this specification, "about", "substantially", etc. are used in or close to the numerical value when manufacturing and material tolerances inherent in the stated meaning are presented, and are used in a precise sense to aid the understanding of the present invention. or absolute figures are used to prevent unreasonable use by unscrupulous infringers of the mentioned disclosure.

본 발명의 일 예에 따른 고강도, 고성형의 저원가 오스테나이트계 스테인리스강은 중량%로, C: 0% 초과 0.08% 이하, N: 0.2 내지 0.25%, Si: 0.8 내지 1.5%, Mn: 8.0 내지 9.5%, Cr: 15.0 내지 16.5%, Ni: 0% 초과 1.0% 이하, Cu: 0.8 내지 1.8%, 잔부 Fe 및 기타 불가피한 불순물을 포함한다.The high-strength, high-molding, low-cost austenitic stainless steel according to an embodiment of the present invention is, by weight, C: more than 0% and 0.08% or less, N: 0.2 to 0.25%, Si: 0.8 to 1.5%, Mn: 8.0 to 9.5%, Cr: 15.0 to 16.5%, Ni: more than 0% and not more than 1.0%, Cu: 0.8 to 1.8%, balance Fe and other unavoidable impurities.

이하에서는 상기 합금조성에 대해서 한정한 이유에 대하여 구체적으로 설명한다. Hereinafter, the reason for limiting the alloy composition will be described in detail.

탄소(C): 0중량% 초과 0.08중량% 이하Carbon (C): greater than 0% by weight and less than or equal to 0.08% by weight

탄소(C)는 오스테나이트 상 안정화에 효과적인 원소로, 오스테나이트계 스테인리스강의 항복강도를 확보하기 위해 첨가할 수 있다. 다만, 그 함량이 과도할 경우 고용강화 효과에 의해 냉간가공성이 저하되며, Cr탄화물의 입계 석출을 유도하여 연성, 인성, 내식성 등이 저하될 수 있으며, 소재 간 용접 특성이 하락할 수 있다. 이에 따라, 본 발명에서 C 함량의 상한은 0.08중량%로 한정될 수 있다. Carbon (C) is an effective element for stabilizing the austenite phase, and may be added to secure the yield strength of the austenitic stainless steel. However, if the content is excessive, cold workability is reduced due to the solid solution strengthening effect, and ductility, toughness, corrosion resistance, etc. may be reduced by inducing grain boundary precipitation of Cr carbide, and welding properties between materials may be deteriorated. Accordingly, the upper limit of the C content in the present invention may be limited to 0.08% by weight.

질소(N): 0.2 내지 0.25중량%Nitrogen (N): 0.2 to 0.25 wt%

질소(N)는 본 발명에서 가장 중요한 원소 중 하나이다. 질소는 강력한 오스테나이트 상 안정화 원소로, 오스테나이트계 스테인리스강의 내식성 및 항복강도 향상에 효과적인 원소이다. 다만, 그 함량이 과도할 경우 주편 제작 시 질소 기포(pore) 등의 결함이 발생할 수 있으며, 고용강화 효과에 의해 냉간 가공성이 저하될 수 있다. 이에 따라, 본 발명에서 N 함량의 상한은 0.25중량%로 한정될 수 있다.Nitrogen (N) is one of the most important elements in the present invention. Nitrogen is a powerful austenite phase stabilizing element, and is an effective element for improving the corrosion resistance and yield strength of austenitic stainless steels. However, when the content is excessive, defects such as nitrogen pores may occur during production of the cast slab, and cold workability may be deteriorated due to the solid solution strengthening effect. Accordingly, the upper limit of the N content in the present invention may be limited to 0.25% by weight.

실리콘(Si): 0.8 내지 1.5중량%Silicon (Si): 0.8 to 1.5 wt%

실리콘(Si)은 제강공정 중 탈산제 역할을 하며, 내식성을 향상시키는 효과적인 원소이다. 또한, Si은 치환형 원소 중 강재의 항복강도 향상에 효과적인 원소이다. 이러한 효과를 고려하여, 본 발명에서 Si은 0.8중량% 이상 첨가될 수 있다. 그러나, Si은 페라이트상 안정화 원소로써 과다 첨가 시 주조 슬라브 내 델타(δ) 페라이트 형성을 조장하여 열간 가공성을 저하시킬 뿐만 아니라, 재료의 연성 및 충격특성에 악영향을 미칠 수 있다. 이에 따라, 본 발명에서 Si 함량의 상한은 1.5%중량로 한정될 수 있다. Silicon (Si) acts as a deoxidizer during the steelmaking process and is an effective element for improving corrosion resistance. In addition, Si is an effective element for improving the yield strength of steel among substitution-type elements. In consideration of this effect, in the present invention, Si may be added in an amount of 0.8 wt% or more. However, Si, as a ferrite phase stabilizing element, promotes the formation of delta (δ) ferrite in the cast slab when excessively added, thereby reducing hot workability and adversely affecting the ductility and impact properties of the material. Accordingly, the upper limit of the Si content in the present invention may be limited to 1.5% by weight.

망간(Mn): 8.0 내지 9.5중량%Manganese (Mn): 8.0 to 9.5% by weight

망간(Mn)은 본 발명에서 니켈(Ni)을 대체하여 첨가되는 오스테나이트상 안정화 원소로, 가공 유기 마르텐사이트 생성을 억제하여 냉간 가공성을 향상시키기 위해 8.0중량% 이상 첨가될 수 있다. 다만, 그 함량이 과도할 경우 S계 개재물(MnS)을 과량 형성하여 오스테나이트계 스테인리스강의 연성, 인성이 저하될 수 있으며, 제강 공정도중 Mn 흄(fume)을 발생시켜 제조 상 위험성을 동반한다. 또한, 과도한 양의 Mn 첨가는 제품의 내식성을 급격하게 저하시킨다. 이에 따라, 본 발명에서 Mn 함량의 상한은 9.5중량%로 한정될 수 있다. Manganese (Mn) is an austenite phase stabilizing element added to replace nickel (Ni) in the present invention, and may be added in an amount of 8.0 wt % or more to suppress the formation of processing-induced martensite to improve cold workability. However, if the content is excessive, the ductility and toughness of austenitic stainless steel may be deteriorated by excessive formation of S-based inclusions (MnS), and Mn fumes are generated during the steelmaking process, which accompanies manufacturing risks. In addition, the addition of an excessive amount of Mn sharply deteriorates the corrosion resistance of the product. Accordingly, the upper limit of the Mn content in the present invention may be limited to 9.5% by weight.

크롬(Cr): 15.0 내지 16.5중량%Chromium (Cr): 15.0 to 16.5 wt%

크롬(Cr)은 페라이트 안정화 원소이지만, 마르텐사이트 상 생성 억제에 있어서 효과적이며, 스테인리스강에 요구되는 내식성을 확보하는 기본 원소로, 15.0중량% 이상 첨가될 수 있다. 다만, 그 함량이 과도할 경우 페라이트 안정화 원소로써 슬라브 내 델타(δ) 페라이트를 다량 형성하여 열간 가공성의 저하와 재질 특성에 악영향을 초래할 수 있다. 이에 따라, 본 발명에서 Cr 함량의 상한은 16.5중량%로 한정될 수 있다.Chromium (Cr) is a ferrite stabilizing element, but is effective in suppressing martensite phase formation, and is a basic element for securing corrosion resistance required for stainless steel, and may be added in an amount of 15.0 wt % or more. However, if the content is excessive, a large amount of delta (δ) ferrite in the slab is formed as a ferrite stabilizing element, which may adversely affect hot workability and material properties. Accordingly, the upper limit of the Cr content in the present invention may be limited to 16.5% by weight.

니켈(Ni): 0중량% 초과 1.0중량% 이하Nickel (Ni): greater than 0% by weight and less than or equal to 1.0% by weight

니켈(Ni)은 강력한 오스테나이트 상 안정화 원소이며, 양호한 열간 가공성 및 냉간 가공성을 확보하기 위해 첨가된다. 그러나, Ni은 고가의 원소이므로 다량 첨가 시 원료비용의 상승을 초래한다. 본 발명에서 Ni 함량의 상한은 강재의 비용 및 효율성을 모두 고려하여 1.0중량%로 한정될 수 있다.Nickel (Ni) is a strong austenite phase stabilizing element, and is added to ensure good hot workability and cold workability. However, since Ni is an expensive element, it causes an increase in raw material cost when added in a large amount. In the present invention, the upper limit of the Ni content may be limited to 1.0% by weight in consideration of both the cost and efficiency of the steel.

구리(Cu): 0.8 내지 1.8중량%Copper (Cu): 0.8 to 1.8 wt%

구리(Cu)는 오스테나이트 상 안정화 원소로, 본 발명에서 니켈(Ni)을 대체하여 첨가되는 원소이다. 또한, Cu는 환원 환경에서 강재의 내식성을 향상시키는 원소로 0.8중량% 이상 첨가할 수 있다. 다만, 그 함량이 과도할 경우 강재 비용의 상승뿐만 아니라, 액상화 및 저온 취성의 문제가 있다. 또한, Cu는 과다 첨가 시 슬라브 엣지에 편석되어 강재의 열간 가공성을 저하시키는 문제가 있다. 본 발명에서 Cu 함량의 상한은 강재의 비용, 효율성 및 재질특성을 고려하여 1.8중량%로 한정될 수 있다. Copper (Cu) is an austenite phase stabilizing element, and is added to replace nickel (Ni) in the present invention. In addition, Cu is an element that improves the corrosion resistance of the steel in a reducing environment, it can be added 0.8% by weight or more. However, when the content is excessive, there is a problem of liquefaction and low-temperature brittleness as well as an increase in the cost of steel. In addition, Cu segregates at the slab edge when excessively added, thereby deteriorating the hot workability of the steel. In the present invention, the upper limit of the Cu content may be limited to 1.8% by weight in consideration of the cost, efficiency, and material properties of the steel.

본 발명의 나머지 성분은 철(Fe)이다. 다만, 통상의 제조 과정에서는 원료 또는 주위 환경으로부터 의도되지 않는 불순물들이 불가피하게 혼입될 수 있으므로, 이를 배제할 수는 없다. 상기 불순물들은 통상의 제조 과정의 기술자라면 누구라도 알 수 있는 것이기 때문에 그 모든 내용을 특별히 본 명세서에서 언급하지는 않는다.The remaining component of the present invention is iron (Fe). However, since unintended impurities from raw materials or the surrounding environment may inevitably be mixed in the normal manufacturing process, this cannot be excluded. Since the impurities are known to any person skilled in the art of a conventional manufacturing process, all details thereof are not specifically mentioned in the present specification.

불가피하게 혼입되는 불순물의 예로 인(P), 황(S)이 있으며, 그 함량은 본 발명의 일 예에 따르면 P: 0.035중량% 이하, S: 0.01중량% 이하 중 1종 이상이 포함될 수 있다. Examples of impurities that are unavoidably incorporated include phosphorus (P) and sulfur (S), and the content thereof may include at least one of P: 0.035 wt% or less, S: 0.01 wt% or less, according to an example of the present invention. .

인(P): 0.035중량% 이하Phosphorus (P): 0.035 wt% or less

인(P)은 강 중 불가피하게 함유되는 불순물로, 강재의 입계 부식을 일으키거나 열간 가공성을 저해하는 주요 원인이 되는 원소이므로, 그 함량을 가능한 낮게 제어하는 것이 바람직하다. 본 발명에서 P 함량의 상한은 0.035중량% 이하로 제한될 수 있다.Phosphorus (P) is an impurity that is unavoidably contained in steel and is an element that causes intergranular corrosion of steel or inhibits hot workability, so it is preferable to control its content as low as possible. In the present invention, the upper limit of the P content may be limited to 0.035% by weight or less.

황(S): 0.01중량% 이하Sulfur (S): 0.01 wt% or less

황(S)은 강 중 불가피하게 함유되는 불순물로, 강재의 결정립계에 편석되어 열간 가공성을 저해하는 주요 원인이 되는 원소이므로, 그 함량을 가능한 낮게 제어하는 것이 바람직하다. 본 발명에서 S 함량의 상한은 0.01중량% 이하로 제한될 수 있다. Sulfur (S) is an impurity that is unavoidably contained in steel, and is an element that segregates at grain boundaries of steel and is a major cause of impairing hot workability, so it is preferable to control its content as low as possible. In the present invention, the upper limit of the S content may be limited to 0.01% by weight or less.

강재의 경량화 및 안정성을 위해서는 강재의 항복강도의 향상이 중요하다. 또한, 배터리 모듈케이스를 포함한 다양한 형상의 구조재의 제작을 위해서 충분한 연신율을 확보하여야 한다. 또한, 오스테나이트계 스테인리스강의 가격 경쟁력을 확보하기 위해서는 Ni 등 고가의 오스테나이트 안정화 원소의 함량을 줄이고, 이를 대체할 수 있는 Mn, N, Cu 첨가량을 적절히 조절하여야 한다. It is important to improve the yield strength of steel for light weight and stability. In addition, sufficient elongation must be secured for the manufacture of structural materials of various shapes including the battery module case. In addition, in order to secure price competitiveness of austenitic stainless steel, it is necessary to reduce the content of expensive austenite stabilizing elements such as Ni, and to appropriately control the amount of Mn, N, and Cu added to replace them.

하지만, Ni을 저감하고, Mn, N, Cu를 첨가하는 경우 가공 경화를 급격하게 증가시켜 강재의 연신율을 저하시키거나, 열간 변형저항의 감소를 유발하여 생산성을 저하시키는 위험성을 내포하기 때문에 각 합금원소들의 조화를 고려하여야 한다. 이상과 같이 강재의 항복강도, 연신율, 가격 경쟁력 등을 고려하여 본 발명에 따르면 상술한 합금조성 외 아래의 식 (1) 내지 (4)에 따라 합금조성을 더욱 한정할 수 있다. However, when reducing Ni and adding Mn, N, and Cu, work hardening is rapidly increased to decrease the elongation of the steel, or to reduce the hot deformation resistance by causing a decrease in productivity. The harmony of the elements should be considered. According to the present invention in consideration of the yield strength, elongation, price competitiveness, etc. of the steel as described above, in addition to the alloy composition described above, the alloy composition may be further limited according to the following formulas (1) to (4).

본 발명에서는 냉간 압연하여 냉연재를 마련한 다음, 소둔하여 마련된 냉연소둔재의 우수한 연신율 확보를 위해 오스테나이트 상 분율에 관한 식 (1)을 도출하였다. In the present invention, the formula (1) regarding the austenite phase fraction was derived to secure excellent elongation of the cold rolled annealed material prepared by cold rolling and then annealing.

(1) Ni+0.47Mn+15N ≥ 7.5(1) Ni+0.47Mn+15N ≥ 7.5

여기서, Mn, Ni, N는 각 원소의 함량(중량%)을 의미한다.Here, Mn, Ni, and N mean the content (% by weight) of each element.

식 (1)의 값이 낮을수록 소둔 후 오스테나이트 상의 분율이 낮아지게 되며, 식 (1)의 값이 7.5 미만인 경우 오스테나이트계 스테인리스강은 5% 이상의 델타 페라이트를 포함하거나 냉간 압연 도중 마르텐사이트 상으로의 상변태가 발생하게 된다. 그 결과, 오스테나이트계 스테인리스강의 연신율이 열위해질 수 있으므로, 본 발명에서는 강재의 충분한 연신율을 확보하기 위하여 식 (1)의 값 하한은 7.5로 한정될 수 있다. The lower the value of Equation (1), the lower the fraction of the austenite phase after annealing. When the value of Equation (1) is less than 7.5, the austenitic stainless steel contains 5% or more of delta ferrite or the martensitic phase during cold rolling. A phase transformation will occur. As a result, since the elongation of the austenitic stainless steel may be inferior, in the present invention, the lower limit of the value of Equation (1) may be limited to 7.5 in order to secure a sufficient elongation of the steel material.

또한, 본 발명에서는 오스테나이트계 스테인리스강의 높은 항복강도 확보를 위하여 강재의 응력장(stress field)에 의한 항복강도 향상을 고려하여 식 (2)를 도출하였다. In addition, in the present invention, Equation (2) was derived in consideration of the improvement of the yield strength by the stress field of the steel material in order to secure the high yield strength of the austenitic stainless steel.

(2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12(2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12

여기서, C, N, Si, Mn, Cr, Ni, Cu는 각 원소의 함량(중량%)을 의미한다. Here, C, N, Si, Mn, Cr, Ni, and Cu mean the content (% by weight) of each element.

식 (2)의 값이 높을수록 합금원소 간의 원자 크기 차이에 의하여 격자 사이의 응력장이 증가하여 외부 응력에 대항하여 소성변형을 인내하는 한계가 증가하게 된다. 식 (2)의 값이 12 미만인 경우 본 발명에서 요구하는 항복강도의 확보가 어렵다. 이에 따라, 본 발명에서는 고강도 특성을 위하여 식 (2)의 값 하한은 12로 한정될 수 있다. As the value of Equation (2) is higher, the stress field between the lattices increases due to the atomic size difference between the alloying elements, and the limit to withstand plastic deformation against external stress increases. When the value of Equation (2) is less than 12, it is difficult to secure the yield strength required in the present invention. Accordingly, in the present invention, the lower limit of the value of Equation (2) may be limited to 12 for high strength characteristics.

또한, 본 발명에서는 오스테나이트계 스테인리스강의 변형에 의한 상변태를 고려하여 식 (3)을 도출하였다. In addition, in the present invention, Equation (3) was derived in consideration of the phase transformation due to deformation of the austenitic stainless steel.

(3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70(3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70

여기서, C, N, Si, Mn, Cr, Ni, Cu는 각 원소의 함량(중량%)을 의미한다. Here, C, N, Si, Mn, Cr, Ni, and Cu mean the content (% by weight) of each element.

식 (3)의 값이 높을수록 오스테나이트상이 외부의 응력에 의해서 쉽게 마르텐사이트로 변형된다. 구체적으로, 식 (3)의 값이 70을 초과하는 경우 오스테나이트계 스테인리스강은 변형에 대해서 급격한 가공 유기 마르텐사이트 변태 거동을 보이며, 불균일한 소성 가공이 발생한다. 그 결과, 오스테나이트계 스테인리스강의 연신율이 열위해지는 문제가 있어 식 (3)의 값 상한은 70으로 한정될 수 있다. As the value of Equation (3) is higher, the austenite phase is easily transformed into martensite by external stress. Specifically, when the value of Equation (3) exceeds 70, the austenitic stainless steel exhibits abrupt work-induced martensitic transformation behavior with respect to deformation, and non-uniform plastic working occurs. As a result, there is a problem in that the elongation of the austenitic stainless steel is inferior, so the upper limit of the value of Equation (3) may be limited to 70.

또한, 오스테나이트계 스테인리스강의 변형에 의한 강재의 전위 슬립거동을 고려하여 식 (4)를 도출하였다.In addition, Equation (4) was derived by considering the dislocation slip behavior of the steel due to the deformation of the austenitic stainless steel.

(4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17(4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17

여기서, C, N, Si, Mn, Cr, Ni, Cu는 각 원소의 함량(중량%)을 의미한다.Here, C, N, Si, Mn, Cr, Ni, and Cu mean the content (% by weight) of each element.

식 (4)의 값이 낮을수록 오스테나이트상이 외부의 응력에 의해서 크로스(cross) 슬립 발현이 어렵다. 식 (4)의 값이 11 미만인 경우 오스테나이트계 스테인리스강은 변형에 대해서 플래너(planar) 슬립 거동만을 보이게 되어 외부 응력에 의해서 전위의 축적이 급격하게 발생한다. 그 결과, 불균일한 소성 가동 및 높은 가공경화의 문제점이 있다. 이에 따라, 오스테나이트계 스테인리스강의 연신율이 열위해지고, 조질 압연 수행이 어려우며, 고온에서 열간 변형 시 엣지(edge) 크랙과 같은 열연 결함이 발생하여 생산성 저하 문제가 발생할 가능성이 있다. 이를 고려하여 식 (4)의 값 하한은 11로 한정될 수 있다.The lower the value of Equation (4), the more difficult the cross-slip expression of the austenite phase due to external stress. When the value of Equation (4) is less than 11, the austenitic stainless steel shows only planar slip behavior with respect to deformation, and the accumulation of dislocations occurs rapidly due to external stress. As a result, there are problems of non-uniform plastic operation and high work hardening. Accordingly, the elongation of the austenitic stainless steel is inferior, it is difficult to perform temper rolling, and hot rolling defects such as edge cracks occur during hot deformation at high temperature, which may cause a problem of productivity decrease. In consideration of this, the lower limit of the value of Equation (4) may be limited to 11.

반면, 식 (4)의 값이 커지게 되면 빈번한 크로스 슬립의 발현에 의해 강재의 취약 부분에 응력집중이 증가하는 소성 불균일이 커지게 되는 문제가 있다. 강재의 강도가 높을수록 이러한 취성과 소성 불균일의 경향이 커지기 때문에, 본 발명과 같이 고강도 강재의 경우라면 강재의 연신율 하락이 야기될 가능성이 높다. 이를 고려하여 본 발명에서 식 (4)의 상한은 17로 한정될 수 있다.On the other hand, when the value of Equation (4) is increased, there is a problem in that the plasticity non-uniformity increases due to the occurrence of frequent cross-slip, which increases the stress concentration in the weak part of the steel. As the strength of the steel increases, the tendency of such brittleness and plasticity non-uniformity increases, so that in the case of high-strength steel as in the present invention, a decrease in the elongation of the steel is likely to occur. In consideration of this, the upper limit of Equation (4) in the present invention may be limited to 17.

상용 300계 오스테나이트계 스테인리스강 대비 Ni을 저감한 Cr-Mn 강은 열간 가공성이 낮아 열간 가공 시 엣지 크랙(edge crack) 등에 의한 실수율 하락과 정정비용이 증가하거나, 엣지 크랙 저감을 위한 추가적인 설비 투자가 필요한 문제가 있다. 본 발명에 따르면 상술한 합금원소 성분범위 및 식 (1) 내지 (4)를 이용한 합금조성 성분계의 적절한 설계를 통하여 별도의 공정 및 설비의 추가 없이 우수한 열간 가공성 확보가 가능하다. 본 발명의 일 예에 따르면, 상술한 합금조성을 갖는 주편은 800℃ 이상의 고온에서 단면 감소율이 50% 이상일 수 있다. Cr-Mn steel, which has reduced Ni compared to commercial 300 series austenitic stainless steel, has low hot workability, so error rate decreases due to edge cracks during hot working, correction cost increases, or additional facility investment to reduce edge cracks There is a problem that requires According to the present invention, it is possible to secure excellent hot workability without the addition of a separate process and equipment through the appropriate design of the alloy composition component system using the above-described alloy element range and formulas (1) to (4). According to an example of the present invention, the slab having the above-described alloy composition may have a reduction in cross-section of 50% or more at a high temperature of 800° C. or more.

본 발명의 일 예에 따른 고강도, 고성형의 저원가 오스테나이트계 스테인리스강은 냉연소둔재의 항복강도가 400MPa 이상일 수 있다. 또한, 본 발명의 일 예에 따른 고강도, 고성형의 저원가 오스테나이트계 스테인리스강은 냉연소둔재의 연신율이 55% 이상일 수 있다. 여기서, "냉연소둔재"는 주편을 열간 압연-소둔-냉간 압연-소둔 처리하여 마련되는 강재를 의미한다. In the low-cost austenitic stainless steel of high strength and high formability according to an embodiment of the present invention, the yield strength of the cold-rolled annealed material may be 400 MPa or more. In addition, in the low-cost austenitic stainless steel of high strength and high formability according to an embodiment of the present invention, the elongation of the cold-rolled annealing material may be 55% or more. Here, "cold-rolled annealing material" means a steel material prepared by hot-rolling-annealing-cold rolling-annealing of a slab.

본 발명의 일 예에 따른 고강도, 고성형의 저원가 오스테나이트계 스테인리스강은 조질압연재의 항복강도가 800MPa 이상일 수 있다. 또한, 일 예에 따르면 특히 항복강도가 800MPa 이상이면서, 연신율이 25% 이상일 수 있다. 여기서, "조질압연재"는 상술한 냉연소둔재를 조질 압연하여 마련되는 강재를 의미한다. In the low-cost austenitic stainless steel of high strength and high formability according to an embodiment of the present invention, the yield strength of the temper rolled material may be 800 MPa or more. In addition, according to an example, in particular, the yield strength may be 800 MPa or more, and the elongation may be 25% or more. Here, "passage-rolled material" means a steel material prepared by temper rolling the above-described cold-rolled annealed material.

다음으로, 본 발명에 따른 고강도, 고성형의 저원가 오스테나이트계 스테인리스강의 제조방법에 대하여 설명한다. Next, a method for manufacturing a high-strength, high-molding, low-cost austenitic stainless steel according to the present invention will be described.

본 발명의 일 예에 따른 고강도, 고성형의 저원가 오스테나이트계 스테인리스강의 제조방법은 중량%로, C: 0% 초과 0.08% 이하, N: 0.2 내지 0.25%, Si: 0.8 내지 1.5%, Mn: 8.0 내지 9.5%, Cr: 15.0 내지 16.5%, Ni: 0% 초과 1.0% 이하, Cu: 0.8 내지 1.8%, 잔부 Fe 및 기타 불가피한 불순물을 포함하고, 식 (1) 내지 (4)를 만족하는 주편을 마련하는 단계, 상기 주편을 열간 압연하여 열연재를 마련한 다음, 소둔하여 열연소둔재를 마련하는 단계, 상기 열연소둔재를 냉간 압연하여 냉연재를 마련한 다음, 1050℃ 이상의 온도로 소둔하여 냉연소둔재를 마련하는 단계 및 조질 압연하여 조질압연재를 마련하는 단계를 포함할 수 있다. The method for manufacturing high-strength, high-molding, low-cost austenitic stainless steel according to an embodiment of the present invention is, in weight %, C: more than 0% and 0.08% or less, N: 0.2 to 0.25%, Si: 0.8 to 1.5%, Mn: 8.0 to 9.5%, Cr: 15.0 to 16.5%, Ni: more than 0% and 1.0% or less, Cu: 0.8 to 1.8%, the balance Fe and other unavoidable impurities, and the cast steel that satisfies formulas (1) to (4) preparing a hot-rolled material by hot rolling the slab, then annealing to prepare a hot-rolled annealed material, cold rolling the hot-rolled annealed material to prepare a cold-rolled material, and then annealing at a temperature of 1050 ° C. or higher to cold-rolled It may include the step of providing a blunt material and a step of temper rolling to provide a temper rolled material.

합금원소 함량의 수치, 식 (1) 내지 (4)에 대한 한정 이유는 상술한 바와 같으며, 이하에서 각 제조단계에 대해서 상세히 설명한다. The reason for limiting the numerical value of the alloying element content, formulas (1) to (4) is as described above, and each manufacturing step will be described in detail below.

상술한 합금조성을 가진 주편은 1000 내지 1300℃의 온도에서 열간 압연되어 열연재로 마련될 수 있으며, 이어서 1000 내지 1100℃의 온도 범위에서 소둔되어 열연소둔재로 제조될 수 있다. 이때, 소둔 열처리는 10초 내지 10분 동안 수행될 수 있다. The cast steel having the above-described alloy composition may be prepared as a hot-rolled material by hot rolling at a temperature of 1000 to 1300 °C, and then annealing at a temperature range of 1000 to 1100 °C to manufacture a hot-rolled annealing material. At this time, the annealing heat treatment may be performed for 10 seconds to 10 minutes.

그 다음, 열연소둔재를 냉간 압연하여 냉연재를 마련한 다음, 소둔하여 냉연 소둔재로 제조할 수 있다. 종래에는 오스테나이트계 스테인리스강의 항복강도를 향상시키기 위한 방법으로 냉간 압연한 다음, 1000℃ 이하의 저온도역에서 저온 소둔 열처리를 수행하였다. 저온 소둔 열처리는 재결정을 완료시키지 않고, 냉간 압연 시 강재에 축적된 에너지를 이용하여 강도를 높이는 방법이다. 그러나, 이와 같이 저온 소둔 열처리가 수행된 오스테나이트계 스테인리스강은 재질이 불균일하게 나타날 가능성이 존재할 뿐만 아니라, 후속하는 공정인 산세공정에서 미산세가 발생하거나, 표면형상이 미려하지 못하다는 단점이 있다.Then, the hot-rolled annealing material may be cold-rolled to prepare a cold-rolled material, and then annealed to produce a cold-rolled annealed material. Conventionally, cold rolling was performed as a method for improving the yield strength of austenitic stainless steel, and then low temperature annealing heat treatment was performed in a low temperature range of 1000° C. or less. Low-temperature annealing heat treatment does not complete recrystallization, but is a method of increasing strength by using the energy accumulated in the steel during cold rolling. However, the austenitic stainless steel that has been subjected to the low-temperature annealing heat treatment as described above has the disadvantage that not only there is a possibility that the material may appear non-uniform, but also fine pickling occurs in the pickling process, which is a subsequent process, or the surface shape is not beautiful.

본 발명의 일 예에 따르면 열연소둔재를 냉간 압연하여 냉연재를 마련한 다음, 1050℃ 이상의 온도에서 소둔하여 냉연소둔재로 제조할 수 있다. 이때, 소둔 열처리는 10초 내지 10분 동안 수행될 수 있다. According to an example of the present invention, the hot-rolled annealed material may be cold-rolled to prepare a cold-rolled material, and then annealed at a temperature of 1050° C. or higher to manufacture a cold-rolled annealed material. At this time, the annealing heat treatment may be performed for 10 seconds to 10 minutes.

본 발명에 따르면, 냉간 압연 이후 저온 소둔을 수행하지 않아 우수한 연신율을 확보할 수 있으며, 합금조성 설계를 통하여 항복강도도 적정 수준 이상으로 확보할 수 있다. According to the present invention, excellent elongation can be secured by not performing low-temperature annealing after cold rolling, and yield strength can also be secured at an appropriate level or more through alloy composition design.

본 발명의 일 예에 따른 냉연소둔재는 항복강도가 400MPa 이상일 수 있다. The cold-rolled annealed material according to an embodiment of the present invention may have a yield strength of 400 MPa or more.

본 발명의 일 예에 따른 냉연소둔재는 연신율이 55% 이상일 수 있다. The cold-rolled annealed material according to an embodiment of the present invention may have an elongation of 55% or more.

이와 같이 합금조성 설계를 통하여 생산 및 유통에 부하가 없는 공정을 수행하여 저온 소둔을 진행하지 않고도, 냉연소둔재의 적절한 항복강도를 확보할 수 있어 우수한 가격 경쟁력을 확보할 수 있다. Thus, through the alloy composition design, it is possible to secure the appropriate yield strength of the cold-rolled annealed material without performing a process without a load on production and distribution, thereby securing excellent price competitiveness.

또한, 본 발명에 따르면 냉간 압연 이후 저온 소둔을 수행하지 않음에도 합금조성의 제어 및 후속되는 조질 압연을 통하여 우수한 항복강도를 확보할 수 있다. 본 발명의 일 예에 따르면 조질압연재의 항복강도는 800MPa 이상일 수 있다. 조질 압연은 일 예에 따르면 압하율 20% 이상으로 수행될 수 있다. In addition, according to the present invention, it is possible to secure excellent yield strength through control of alloy composition and subsequent temper rolling even without performing low-temperature annealing after cold rolling. According to an example of the present invention, the yield strength of the temper rolled material may be 800 MPa or more. According to an example, the temper rolling may be performed at a reduction ratio of 20% or more.

조질 압연(skin pass rolling)은 냉간 변형 중에 오스테나이트 상이 가공 유기 마르텐사이트 상으로 변태함에 따라 높은 가공 경화가 나타나는 현상을 이용하거나, 강재의 전위 쌓임을 이용하여 강도를 높일 수 있다. 그러나, 조질 압연을 수행하면 강재의 연신율이 급격히 저하될 우려가 있다. In skin pass rolling, strength can be increased by using a phenomenon in which high work hardening occurs as an austenite phase transforms into a work-induced martensite phase during cold deformation, or by using dislocation accumulation of steel. However, when the temper rolling is performed, there is a fear that the elongation of the steel material is rapidly reduced.

본 발명은 상술한 바와 같이 합금조성을 설계함으로써 강재의 상변태와 전위 거동을 적절히 제어하여 조질 압연으로 강재의 연신율이 급격히 저하되는 것을 방지할 수 있다. 그 결과, 본 발명에 따르면 조질 압연을 수행하여도 조질압연재의 항복강도가 800MPa 이상이며, 연신율이 25% 이상의 고강도 특성과 고성형 특성을 동시에 만족하는 고강도, 고성형의 저원가 오스테나이트계 스테인리스강을 제공할 수 있다.According to the present invention, by designing the alloy composition as described above, it is possible to appropriately control the phase transformation and dislocation behavior of the steel, thereby preventing the elongation of the steel from rapidly decreasing due to the temper rolling. As a result, according to the present invention, even when temper rolling is performed, the yield strength of the temper rolled material is 800 MPa or more, and the high strength, high formability and low cost austenitic stainless steel with an elongation of 25% or more and high forming characteristics are simultaneously satisfied. can provide

이하, 실시예를 통하여 본 발명을 보다 구체적으로 설명하고자 한다. 다만, 하기의 실시예는 본 발명을 예시하여 보다 상세하게 설명하기 위한 것일 뿐, 본 발명의 권리범위를 한정하기 위한 것이 아니라는 점에 유의할 필요가 있다. 본 발명의 권리범위는 특허청구범위에 기재된 사항과 이로부터 합리적으로 유추되는 사항에 의해 결정되는 것이기 때문이다.Hereinafter, the present invention will be described in more detail through examples. However, it is necessary to note that the following examples are only intended to illustrate the present invention in more detail and are not intended to limit the scope of the present invention. This is because the scope of the present invention is determined by the matters described in the claims and matters reasonably inferred therefrom.

{실시예}{Example}

하기 표 1의 합금조성을 갖는 강재를 잉곳(Ingot) 용해를 통해 슬라브로 제조하고, 1250℃에서 2시간 가열한 다음, 열간 압연하여 열연재로 제조하였다. 이후 1100℃에서 90초간 소둔 열처리를 수행하여 열연소둔재로 제조하였다. 이어서, 70%의 압하율로 냉간 압연을 수행하여 냉연재를 제조한 다음, 1100℃에서 10초간 소둔 열처리를 수행하여 냉연소둔재를 마련하였다.A steel material having an alloy composition shown in Table 1 was prepared as a slab through ingot melting, heated at 1250° C. for 2 hours, and then hot rolled to prepare a hot rolled material. Thereafter, annealing heat treatment was performed at 1100° C. for 90 seconds to prepare a hot-rolled annealed material. Then, cold rolling was performed at a reduction ratio of 70% to prepare a cold rolled material, and then annealed heat treatment was performed at 1100° C. for 10 seconds to prepare a cold rolled annealed material.

각 발명예 및 비교예에 대한 합금 조성과 합금원소 함량을 대입하여 도출한 아래 식 (1) 내지 식 (4)의 값을 아래 표 1에 나타내었다. Table 1 below shows the values of Equations (1) to (4) derived by substituting the alloy composition and alloying element content for each Inventive Example and Comparative Example.

(1) Ni+0.47Mn+15N ≥ 7.5(1) Ni+0.47Mn+15N ≥ 7.5

(2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12(2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12

(3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70(3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70

(4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17(4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17

성분(중량%)Ingredients (wt%) 식(1)Formula (1) 식(2)Equation (2) 식(3)Equation (3) 식(4)Equation (4) CC SiSi MnMn NiNi CrCr CuCu NN 비교예1Comparative Example 1 0.060.06 0.40.4 1.11.1 8.18.1 18.218.2 0.10.1 0.040.04 9.229.22 9.279.27 5.075.07 18.0018.00 비교예2Comparative Example 2 0.050.05 2.02.0 9.59.5 0.10.1 16.016.0 2.02.0 0.130.13 6.526.52 12.0312.03 92.3992.39 0.020.02 비교예3Comparative Example 3 0.080.08 1.01.0 7.07.0 0.50.5 15.015.0 1.01.0 0.160.16 6.196.19 11.4811.48 125.22125.22 10.6410.64 비교예4Comparative Example 4 0.080.08 0.50.5 6.06.0 0.50.5 15.015.0 1.01.0 0.160.16 5.725.72 10.7310.73 137.92137.92 13.0513.05 비교예5Comparative Example 5 0.060.06 1.01.0 7.07.0 0.20.2 15.015.0 2.02.0 0.170.17 6.046.04 11.4211.42 109.54109.54 9.299.29 비교예6Comparative Example 6 0.060.06 2.02.0 8.08.0 0.20.2 15.015.0 2.02.0 0.190.19 6.816.81 13.2813.28 83.0083.00 6.156.15 비교예7Comparative Example 7 0.060.06 1.01.0 8.08.0 0.20.2 15.015.0 1.51.5 0.200.20 6.966.96 12.0912.09 102.08102.08 12.3812.38 비교예8Comparative Example 8 0.060.06 1.21.2 8.18.1 0.60.6 15.615.6 2.12.1 0.210.21 7.567.56 12.9712.97 57.5957.59 12.5812.58 비교예9Comparative Example 9 0.060.06 1.71.7 8.98.9 0.20.2 16.016.0 2.02.0 0.210.21 7.537.53 13.6813.68 55.5355.53 9.239.23 비교예10Comparative Example 10 0.060.06 2.22.2 8.28.2 0.70.7 15.315.3 2.22.2 0.190.19 7.407.40 13.8013.80 55.1355.13 6.056.05 비교예11Comparative Example 11 0.300.30 1.01.0 6.06.0 0.20.2 16.016.0 0.00.0 0.180.18 5.725.72 16.8316.83 46.4446.44 21.9521.95 비교예12Comparative Example 12 0.200.20 1.01.0 7.07.0 0.20.2 16.016.0 0.00.0 0.180.18 6.196.19 14.6314.63 84.5484.54 17.5417.54 발명예1Invention Example 1 0.080.08 1.01.0 8.98.9 1.01.0 16.016.0 1.01.0 0.200.20 8.188.18 12.9512.95 63.1563.15 15.1715.17 발명예2Invention Example 2 0.060.06 1.01.0 8.68.6 0.80.8 15.715.7 1.71.7 0.210.21 7.997.99 12.7412.74 59.8159.81 14.3114.31 발명예3Invention example 3 0.060.06 1.01.0 9.09.0 1.01.0 15.815.8 1.31.3 0.230.23 8.688.68 13.2113.21 51.7651.76 16.7916.79 발명예4Invention Example 4 0.070.07 1.051.05 8.78.7 0.90.9 15.615.6 1.31.3 0.210.21 8.148.14 12.9512.95 63.9963.99 15.0315.03

각 발명예, 비교예의 냉연소둔재에 대한 항복강도, 인장강도, 연신율을 측정하였다. 또한, 각 발명예, 비교예의 냉연소둔재를 20% 조질 압연하여 마련된 조질압연재에 대한 항복강도, 인장강도, 연신율을 측정하였다. The yield strength, tensile strength, and elongation of the cold-rolled annealed materials of each invention example and comparative example were measured. In addition, the yield strength, tensile strength, and elongation of the temper-rolled material prepared by 20% temper rolling of the cold-rolled annealed material of each invention example and comparative example were measured.

항복강도, 인장강도, 연신율의 측정은 ASTM 규격에 의거하여 진행하였고, 그에 따라 측정된 항복강도(Yield Strength(YS), MPa), 인장강도(Tensile Strength(TS), MPa) 및 연신율(Elongation(EL), %)을 아래 표 2에 기재하였다. 또한, 소둔재의 180°밀착 굽힘 시험 시 크랙(crack) 발생여부를 아래 표 2에 함께 기재하였다.Yield strength, tensile strength, and elongation were measured according to ASTM standards, and yield strength (YS), MPa), tensile strength (Tensile Strength (TS), MPa) and elongation (Elongation ( EL), %) are shown in Table 2 below. In addition, the occurrence of cracks during the 180° adhesion bending test of the annealed material is also described in Table 2 below.

냉연재cold rolled material 조질 압연재temper rolling material 굽힘
크랙
(○/×)flex
crack
(○/×) YS
(MPa)YS
(MPa) TS
(MPa)ts
(MPa) EL
(%)EL
(%) YS
(MPa)YS
(MPa) TS
(MPa)ts
(MPa) EL
(%)EL
(%) 비교예1Comparative Example 1 300.0 300.0 697.0 697.0 52.2 52.2 624.4624.4 876.3876.3 32.1　32.1 ×× 비교예2Comparative Example 2 501.6501.6 862.1862.1 5555 940.8940.8 1205.31205.3 20.220.2 ○○ 비교예3Comparative Example 3 379.7 379.7 1133.7 1133.7 38.1 38.1 850.4850.4 1517.51517.5 14.9　14.9 ○○ 비교예4Comparative Example 4 311.4 311.4 1324.0 1324.0 28.1 28.1 893.7893.7 1652.21652.2 11.9　11.9 ○○ 비교예5Comparative Example 5 362.9362.9 958.3958.3 39.839.8 920.3920.3 1430.51430.5 20.320.3 ○○ 비교예6Comparative Example 6 435.9435.9 1050.81050.8 58.758.7 918.1918.1 1397.81397.8 26.126.1 ○○ 비교예7Comparative Example 7 461.9461.9 1028.21028.2 50.350.3 953953 1413.91413.9 22.822.8 ○○ 비교예8Comparative Example 8 427.7427.7 878.8878.8 59.759.7 802.8802.8 1210.71210.7 26.726.7 ×× 비교예9Comparative Example 9 457.6457.6 888888 58.758.7 848848 1220.21220.2 27.727.7 ×× 비교예10Comparative Example 10 462.6462.6 930.6930.6 57.357.3 933.6933.6 1332.61332.6 23.723.7 ○○ 비교예11Comparative Example 11 508.7508.7 948.2948.2 32.2　32.2 881.1881.1 1416.81416.8 15.915.9 ○○ 비교예12Comparative Example 12 464.3464.3 914.4　914.4 25.8　25.8 840.5840.5 1313.51313.5 12.312.3 ○○ 발명예1Invention Example 1 435.2435.2 938.1938.1 57.657.6 801.7801.7 12881288 25.525.5 ×× 발명예2Invention Example 2 432.5432.5 878.7878.7 59.559.5 841.8841.8 1233.61233.6 25.525.5 ×× 발명예3Invention example 3 453.1453.1 876.6876.6 60.160.1 894.6894.6 12611261 25.325.3 ×× 발명예4Invention Example 4 442.7442.7 860.5860.5 60.460.4 851.8851.8 1233.11233.1 26.326.3 ××

표 2를 참조하면 본 발명에서 한정하는 합금조성과 식 (1) 내지 (4)를 만족하는 발명예 1 내지 4의 경우, 냉연소둔재는 400MPa 이상의 항복강도, 55% 이상의 연신율 확보 가능함을 알 수 있다. 또한, 표 2를 참조하면 발명예 1 내지 4의 조질압연재는 조질 압연을 수행하여도 항복강도가 800MPa 이상이며, 25% 이상의 충분한 연신율을 확보 가능함을 알 수 있다. 더불어, 발명예 1 내지 4는 Ni 함량이 1.0중량% 이하로 상대적으로 낮아 가격 경쟁력을 확보 가능함을 알 수 있다. Referring to Table 2, in the case of Inventive Examples 1 to 4 satisfying the alloy composition and formulas (1) to (4) defined in the present invention, the cold-rolled annealed material can secure a yield strength of 400 MPa or more and an elongation of 55% or more. . In addition, referring to Table 2, it can be seen that the temper rolling materials of Inventive Examples 1 to 4 have a yield strength of 800 MPa or more and a sufficient elongation of 25% or more even when the temper rolling is performed. In addition, it can be seen that Inventive Examples 1 to 4 have a relatively low Ni content of 1.0% by weight or less, thereby securing price competitiveness.

표 1, 2를 참조하여 비교예를 평가한다. With reference to Tables 1 and 2, the comparative example is evaluated.

비교예 1은 상용적으로 생산되는 규격 오스테나이트계 스테인리스 강으로, 본 발명의 성분 조성 및 식 (2), (3), (4)를 만족하지 못하여 항복강도가 낮았다. 또한, 비교예 1의 상용 오스테나이트계 스테인리스강은 Ni 함량이 8.1중량%로 본 발명 대비 과도한 Ni 첨가로 가격 경쟁력이 열위하였다. Comparative Example 1 was a commercially produced standard austenitic stainless steel, and did not satisfy the composition and formulas (2), (3), and (4) of the present invention, and thus the yield strength was low. In addition, the commercial austenitic stainless steel of Comparative Example 1 had a Ni content of 8.1% by weight and was inferior in price competitiveness due to excessive Ni addition compared to the present invention.

비교예 2는 식 (1)을 만족하지 못하여 냉간 압연한 다음, 소둔 후 강재 내부에 초기 델타 페라이트가 상당 부분 잔류한다. 델타 페라이트 상과 오스테나이트 상의 상계면은 강재의 굽힘과 같은 성형 공정 시 상 차이로 인한 균열 발생이 쉽게 생기기 때문에 낮은 식 (1)의 값은 굽힘 시 균열 발생을 동반한다. 그 결과, 비교예 2는 Si 함량이 높아 항복강도가 높고, 연신율도 준수하지만 잔류하는 델타 페라이트에 의해 굽힘 크랙이 발생하여 굽힘 특성을 포함한 성형성이 열위하였다. Comparative Example 2 did not satisfy Equation (1), so the initial delta ferrite remained substantially inside the steel after cold rolling and then annealing. Since the phase interface between the delta ferrite phase and the austenite phase is prone to cracking due to the phase difference during the forming process such as bending of steel, a low value of Equation (1) accompanies cracking during bending. As a result, Comparative Example 2 had a high Si content, so the yield strength was high, and the elongation was also observed, but bending cracks occurred due to the remaining delta ferrite, so that the formability including the bending properties was inferior.

비교예 3 내지 5는 공통적으로 식 (1) 내지 (4)를 만족하지 못하는 강종으로, 식 (1)을 만족하지 못하여 냉간 압연한 다음, 소둔 후 강재 내부에 초기 델타 페라이트가 상당 부분 잔류하여 굽힘 특성을 포함한 성형성이 열위하였으며, 식 (2)를 만족하지 못하여 항복강도가 낮았다. 또한, 식 (3)의 값이 100 이상으로 식 (3)을 만족하지 못하여 변형 도중 가공 유기 마르텐사이트로의 상변태에 의한 소성 불균일이 쉽게 발생하였다. 또한, 식 (4)의 값이 낮아 식 (4)를 만족하지 못하여 플래너 슬립의 영향으로 전위의 축적이 극심하게 발생하였다. 그 결과, 연신율이 열위하였다. 특히, 비교예 3 내지 5는 식 (3), (4)를 만족하지 못하여 열위해지는 연신율은 조질 압연 후 더욱 저하되어 조질압연재로서 사용하기 적합한 물성을 갖지 않는다.Comparative Examples 3 to 5 are steel grades that do not satisfy Formulas (1) to (4) in common. After cold rolling because they do not satisfy Formula (1), a significant portion of the initial delta ferrite remains inside the steel after annealing and bending Formability including properties was inferior, and Equation (2) was not satisfied, resulting in low yield strength. In addition, since the value of Equation (3) was 100 or more, Equation (3) was not satisfied, and plasticity non-uniformity due to the phase transformation to processing induced martensite easily occurred during deformation. In addition, since the value of Equation (4) was low, Equation (4) was not satisfied, and the accumulation of dislocations occurred extremely due to the influence of planar slip. As a result, the elongation was inferior. In particular, Comparative Examples 3 to 5 do not satisfy the formulas (3) and (4), so that the inferior elongation is further lowered after the temper rolling, so that they do not have suitable physical properties for use as a temper rolling material.

비교예 6은 식 (1)을 만족하지 못하여 냉간 압연한 다음, 소둔 후 강재 내부에 초기 델타 페라이트가 상당 부분 잔류하여 굽힘 특성을 포함한 성형성이 열위하였다. 또한, 비교예 6은 높은 Si 함량과 식 (2) 에 의해 우수한 항복강도는 나타내고 있지만 식 (3)과 식 (4)의 영향으로 충분한 연신율을 확보하지 못하였다.Comparative Example 6 did not satisfy Equation (1) and was cold-rolled, and then a significant portion of initial delta ferrite remained inside the steel after annealing, resulting in inferior formability including bending properties. In addition, Comparative Example 6 showed a high Si content and excellent yield strength by Equation (2), but did not secure sufficient elongation due to the influence of Equations (3) and (4).

비교예 7은 식 (1)을 만족하지 못하여 냉간 압연한 다음, 소둔 후 강재 내부에 초기 델타 페라이트가 상당 부분 잔류하여 굽힘 특성을 포함한 성형성이 열위하였다. 또한, 비교예 7은 식 (3)의 값이 100 이상으로 식 (3)을 만족하지 못하여 변형 도중 가공 유기 마르텐사이트로의 상변태에 의한 소성 불균일이 쉽게 발생하였다. 이로 인해, 냉연소둔재 및 조질압연재의 연신율이 열위하였다.Comparative Example 7 did not satisfy Equation (1) and was cold-rolled, and then a significant portion of initial delta ferrite remained inside the steel after annealing, resulting in inferior formability including bending properties. Also, in Comparative Example 7, the value of Equation (3) was 100 or more, which did not satisfy Equation (3), so that plasticity non-uniformity due to the phase transformation into processing-induced martensite easily occurred during deformation. For this reason, the elongation of the cold rolled annealed material and the temper rolled material was inferior.

비교예 8은 Cu를 제외한 합금원소의 성분조성과 식 (1) 내지 식 (4)를 만족하였다. 이로 인해 냉연소둔재일 때, 우수한 항복강도 및 연신율을 보였다. 그러나, 비교예 8은 과도한 Cu 함량으로 인하여 열위한 열간 가공성을 가지고 있었다. 이에 대한 구체적인 평가는 이후 표 3을 참조하여 후술하도록 한다.Comparative Example 8 satisfies the composition of alloy elements except Cu and Equations (1) to (4). For this reason, it showed excellent yield strength and elongation when cold-rolled annealed material. However, Comparative Example 8 had poor hot workability due to excessive Cu content. A detailed evaluation thereof will be described later with reference to Table 3 below.

비교예 9 내지 10은 과도한 Si, Cu 함량으로 인하여 열위한 열간가공성을 가지고 있었다. 이에 대한 구체적인 평가는 이후 표 3을 참조하여 후술하도록 한다.Comparative Examples 9 to 10 had excessive hot workability due to excessive Si and Cu contents. A detailed evaluation thereof will be described later with reference to Table 3 below.

비교예 11, 12는 식 (1)을 만족하지 못하여 냉간 압연한 다음, 소둔 후 강재 내부에 초기 델타 페라이트가 상당 부분 잔류하여 굽힘 특성을 포함한 성형성이 열위하였다. 또한, 비교예 11, 12는 식 (4)의 값이 과도하여 빈번한 크로스 슬립의 발현에 의해 강재의 취약부분에 응력집중이 증가하는 소성 불균일이 커졌다. 그 결과, 냉연소둔재와 조질압연재의 연신율이 열위하였다. 일반적인 상용 강재의 경우 크로스 슬립에 의한 응력집중이 연신율에 미치는 영향이 미미하지만, 비교예 11, 12와 같이 식 (2)의 값이 높은 고강도 강재에서는 연신율의 하락이 극심하게 발생하였다. Comparative Examples 11 and 12 did not satisfy Equation (1), so after cold rolling, a significant portion of initial delta ferrite remained inside the steel after annealing, resulting in inferior formability including bending properties. In addition, in Comparative Examples 11 and 12, the value of Equation (4) was excessive, and the plasticity non-uniformity in which the stress concentration in the weak part of the steel increased due to the frequent cross-slip expression was increased. As a result, the elongation of the cold rolled annealed material and the temper rolled material was inferior. In the case of general commercial steels, the effect of stress concentration due to cross slip on the elongation is insignificant, but in Comparative Examples 11 and 12, in the high-strength steels having a high value of Equation (2), the elongation decreased significantly.

본 발명에 따른 오스테나이트계 스테인리스강은 열간 가공성이 우수하여 생산성과 실수율이 높아 가격 경쟁력이 우수하다. 열간 가공성을 비교 평가하기 위하여 연신율이 우수한 몇몇 비교예, 발명예 슬라브의 각 온도에서의 단면 감소율(Reduction of Area)를 측정하였다. 단면 감소율의 측정은 ASTM 규격에 의거한 고온 인장시험을 통해 이루어졌으며, 그에 따른 결과는 표 3에 기재하였다. The austenitic stainless steel according to the present invention has excellent hot workability, and thus has high productivity and high error rate, and thus has excellent price competitiveness. In order to compare and evaluate the hot workability, the reduction of area at each temperature of the slabs of several comparative examples and invention examples having excellent elongation was measured. The reduction in area was measured through a high-temperature tensile test based on ASTM standards, and the results are shown in Table 3.

온도별 단면 감소율 (%)Reduction of section by temperature (%) 800℃ 800℃ 900℃ 900℃ 1000℃ 1000℃ 1100℃ 1100℃ 1200℃ 1200℃ 비교예1Comparative Example 1 81.481.4 78.778.7 76.376.3 84.784.7 96.396.3 비교예2Comparative Example 2 40.340.3 43.643.6 53.453.4 66.666.6 88.288.2 비교예6Comparative Example 6 42.542.5 50.550.5 69.569.5 88.188.1 95.295.2 비교예7Comparative Example 7 52.852.8 57.257.2 69.369.3 82.482.4 95.295.2 비교예8Comparative Example 8 43.243.2 48.748.7 64.764.7 85.385.3 93.493.4 비교예9Comparative Example 9 41.241.2 48.5　48.5 55.2　55.2 68.2　68.2 91.0　91.0 비교예10Comparative Example 10 40.940.9 45.6　45.6 55.4　55.4 66.6　66.6 90.2　90.2 발명예1Invention Example 1 53.353.3 6464 75.175.1 88.788.7 96.696.6 발명예2Invention Example 2 50.150.1 54.754.7 71.171.1 87.187.1 97.097.0 발명예3Invention example 3 60.060.0 56.956.9 66.2　66.2 84.5　84.5 95.8　95.8 발명예4Invention Example 4 55.855.8 52.852.8 58.258.2 85.285.2 96.996.9

표 3을 참조하면, 본 발명에서 한정하는 합금조성과 식 (1) 내지 (4)를 만족하는 발명예 1 내지 4의 경우 800℃ 이상의 고온에서의 단면 감소율이 50% 이상 확보할 수 있음을 알 수 있다. Referring to Table 3, it can be seen that in the case of Inventive Examples 1 to 4 satisfying the alloy composition and formulas (1) to (4) defined in the present invention, the reduction in section at a high temperature of 800 ° C. or higher can be secured by 50% or more. can

비교예 1은 상용적으로 생산되는 규격 오스테나이트계 스테인리스강으로, 고강도 특성의 발현에 필요한 Si 또는 Ni 저감을 위해 투입되는 Cu 및 N의 양이 적어 우수한 열간 가공성을 나타낸다. 그러나, 이와 같은 상용 300계 오스테나이트계 스테인리스강은 고가의 Ni 원소를 다량으로 함유하고 있으므로, 가격 경쟁력이 상당히 낮은 단점이 있다. 또한, 표 2에서 평가한 바와 같이 본 발명의 성분 조성 및 식 (2), (3), (4)를 만족하지 못하여 항복강도가 낮았다. Comparative Example 1 is a commercially produced standard austenitic stainless steel, and exhibits excellent hot workability due to small amounts of Cu and N added to reduce Si or Ni required for the expression of high strength characteristics. However, since such commercial 300 series austenitic stainless steel contains a large amount of expensive Ni element, price competitiveness is quite low. In addition, as evaluated in Table 2, the component composition and formulas (2), (3) and (4) of the present invention were not satisfied, so the yield strength was low.

비교예 2, 6, 9, 10은 냉연소둔재의 항복강도 향상을 위해서 과다한 양의 Si을 첨가하였으며, 가격 경쟁력을 위하여 Ni을 대체하여 Cu를 과다하게 첨가하였다. 비교예 2, 6, 9, 10은 Si, Cu 첨가량이 과다하여 열간 가공성이 열위하였다. In Comparative Examples 2, 6, 9, and 10, an excessive amount of Si was added to improve the yield strength of the cold-rolled annealed material, and Cu was excessively added to replace Ni for price competitiveness. In Comparative Examples 2, 6, 9, and 10, the amount of Si and Cu added was excessive, and thus the hot workability was inferior.

비교예 7은 열간 가공성을 저하하는 Si, Cu이 본 발명에서 한정하는 성분 범위 내로 첨가되어 열간 가공성이 우수하였다. 그러나, 표 2에서 평가한 바와 같이 식 (1)을 만족하지 못하여 성형성이 열위하였으며, 식 (3)을 만족하지 못하여 냉연소둔재 및 조질압연재의 연신율이 열위하였다. In Comparative Example 7, Si and Cu, which reduce hot workability, were added within the range of components limited in the present invention, and thus the hot workability was excellent. However, as evaluated in Table 2, the formability was inferior because the formula (1) was not satisfied, and the elongation of the cold rolled annealed material and the temper rolled material was inferior because the formula (3) was not satisfied.

비교예 8은 Cu 첨가량이 본 발명에서 한정하는 범위 외로 과다 첨가되었다. 과다 첨가된 Cu는 슬라브의 엣지나 표면부 상에 편석되어 액화취성 등을 유발하여 비교예 8의 열간 가공성을 열위시켰다. 비교예 8은 열간 가공성이 열위하여 열간 가공 이후 엣지 크랙(edge crack)에 의한 실수율 감소와 정정비용의 증가가 발생하거나, 엣지 크랙 저감을 위한 추가적인 설비 투자가 필요할 우려가 있다. In Comparative Example 8, the amount of Cu added was excessively outside the range limited by the present invention. The excessively added Cu segregated on the edge or surface of the slab to induce liquid embrittlement, etc., thereby inferior to the hot workability of Comparative Example 8. In Comparative Example 8, due to poor hot workability, there is a fear that a decrease in the error rate due to edge cracks and an increase in correction cost after hot working occurs, or additional equipment investment for reducing edge cracks may be required.

상술한 바에 있어서, 본 발명의 예시적인 실시예들을 설명하였지만, 본 발명은 이에 한정되지 않으며 해당 기술 분야에서 통상의 지식을 가진 자라면 다음에 기재하는 청구범위의 개념과 범위를 벗어나지 않는 범위 내에서 다양한 변경 및 변형이 가능함을 이해할 수 있을 것이다.In the foregoing, exemplary embodiments of the present invention have been described, but the present invention is not limited thereto, and those of ordinary skill in the art will not depart from the concept and scope of the following claims. It will be appreciated that various modifications and variations are possible.

본 발명에 따르면 다양한 산업계 전반에 적용될 수 있는 고강도, 고성형의 저원가 오스테나이트계 스테인리스강을 제공할 수 있다. According to the present invention, it is possible to provide a high-strength, high-forming, low-cost austenitic stainless steel that can be applied to various industries.

Claims (8)

중량%로, C: 0% 초과 0.08% 이하, N: 0.2 내지 0.25%, Si: 0.8 내지 1.5%, Mn: 8.0 내지 9.5%, Cr: 15.0 내지 16.5%, Ni: 0% 초과 1.0% 이하, Cu: 0.8 내지 1.8%, 잔부 Fe 및 기타 불가피한 불순물을 포함하고,By weight %, C: more than 0% 0.08% or less, N: 0.2 to 0.25%, Si: 0.8 to 1.5%, Mn: 8.0 to 9.5%, Cr: 15.0 to 16.5%, Ni: more than 0% to 1.0% or less, Cu: 0.8 to 1.8%, the balance contains Fe and other unavoidable impurities, 하기 식 (1) 내지 (4)를 만족하는 고강도, 고성형의 저원가 오스테나이트계 스테인리스강:A high-strength, high-forming, low-cost austenitic stainless steel satisfying the following formulas (1) to (4): (1) Ni+0.47Mn+15N ≥ 7.5(1) Ni+0.47Mn+15N ≥ 7.5 (2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12(2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12 (3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70(3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70 (4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17(4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17 (여기서, C, N, Si, Mn, Cr, Ni, Cu는 각 원소의 함량(중량%)을 의미한다).(Here, C, N, Si, Mn, Cr, Ni, and Cu mean the content (wt%) of each element). 제1항에 있어서, According to claim 1, 냉연소둔재의 항복강도가 400MPa 이상인 고강도, 고성형의 저원가 오스테나이트계 스테인리스강.High-strength, high-forming, low-cost austenitic stainless steel with yield strength of 400 MPa or more of cold-rolled annealed material. 제1항에 있어서, According to claim 1, 냉연소둔재의 연신율이 55% 이상인 고강도, 고성형의 저원가 오스테나이트계 스테인리스강.High-strength, high-forming, low-cost austenitic stainless steel with an elongation of 55% or more of cold-rolled annealed material. 제1항에 있어서, According to claim 1, 조질압연재의 항복강도가 800MPa 이상인 고강도, 고성형의 저원가 오스테나이트계 스테인리스강. High-strength, high-forming, low-cost austenitic stainless steel with yield strength of 800 MPa or more of temper rolling material. 제4항에 있어서, 5. The method of claim 4, 상기 조질압연재의 연신율이 25% 이상인 고강도, 고성형의 저원가 오스테나이트계 스테인리스강.A high-strength, high-forming, low-cost austenitic stainless steel having an elongation of 25% or more of the temper rolling material. 중량%로, C: 0% 초과 0.08% 이하, N: 0.2 내지 0.25%, Si: 0.8 내지 1.5%, Mn: 8.0 내지 9.5%, Cr: 15.0 내지 16.5%, Ni: 0% 초과 1.0% 이하, Cu: 0.8 내지 1.8%, 잔부 Fe 및 기타 불가피한 불순물을 포함하고, 하기 식 (1) 내지 (4)를 만족하는 주편을 마련하는 단계;By weight %, C: more than 0% 0.08% or less, N: 0.2 to 0.25%, Si: 0.8 to 1.5%, Mn: 8.0 to 9.5%, Cr: 15.0 to 16.5%, Ni: more than 0% to 1.0% or less, Cu: 0.8 to 1.8%, including the balance Fe and other unavoidable impurities, preparing a slab that satisfies the following formulas (1) to (4); 상기 주편을 열간 압연하여 열연재를 마련한 다음, 소둔하여 열연소둔재를 마련하는 단계;preparing a hot-rolled material by hot rolling the slab, and then annealing to prepare a hot-rolled annealing material; 상기 열연소둔재를 냉간 압연하여 냉연재를 마련한 다음, 1050℃ 이상의 온도로 소둔하여 냉연소둔재를 마련하는 단계; 및preparing a cold-rolled material by cold-rolling the hot-rolled annealing material, and then annealing at a temperature of 1050° C. or higher to prepare a cold-rolled annealing material; and 조질 압연하여 조질압연재를 마련하는 단계;를 포함하는 고강도, 고성형의 저원가 오스테나이트계 스테인리스강의 제조방법:High-strength, high-molding, low-cost austenitic stainless steel manufacturing method comprising; (1) Ni+0.47Mn+15N ≥ 7.5(1) Ni+0.47Mn+15N ≥ 7.5 (2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12(2) 23(C+N)+1.3Si+0.24(Cr+Ni+Cu)+0.1Mn ≥ 12 (3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70(3) 551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu) ≤ 70 (4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17(4) 11 ≤ 1+45C-5Si+0.09Mn+2.2Ni-0.28Cr-0.67Cu+88.6N ≤ 17 (여기서, C, N, Si, Mn, Cr, Ni, Cu는 각 원소의 함량(중량%)을 의미한다).(Here, C, N, Si, Mn, Cr, Ni, and Cu mean the content (wt%) of each element). 제6항에 있어서,7. The method of claim 6, 상기 조질 압연하는 단계는, The temper rolling step is, 압하율 20% 이상으로 수행하는 고강도, 고성형의 저원가 오스테나이트계 스테인리스강의 제조방법.A method of manufacturing a high-strength, high-forming, low-cost austenitic stainless steel with a reduction ratio of 20% or more. 제6항에 있어서,7. The method of claim 6, 상기 주편은 800℃ 이상의 고온에서 단면 감소율이 50% 이상인 고강도, 고성형의 저원가 오스테나이트계 스테인리스강의 제조방법.The slab is a method of manufacturing a high-strength, high-molding, low-cost austenitic stainless steel having a cross-section reduction of 50% or more at a high temperature of 800° C. or higher.
PCT/KR2021/001345 2020-04-22 2021-02-02 Low-cost austenitic stainless steel having high strength and high formability, and method for manufacturing same Ceased WO2021215630A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP21793437.1A EP4119693A4 (en) 2020-04-22 2021-02-02 Low-cost austenitic stainless steel having high strength and high formability, and method for manufacturing same
CN202180028609.8A CN115398022B (en) 2020-04-22 2021-02-02 Low cost austenitic stainless steel having high strength and high formability and method of manufacturing the same
US17/918,014 US20230142021A1 (en) 2020-04-22 2021-02-02 Low-cost austenitic stainless steel having high strength and high formability, and method for manufacturing same
JP2022564367A JP7395769B2 (en) 2020-04-22 2021-02-02 High strength, high formability, low cost austenitic stainless steel and its manufacturing method

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR1020200048614A KR102385472B1 (en) 2020-04-22 2020-04-22 High-strength, high-formability, low cost austenitic stainless steel and manufacturing method thereof
KR10-2020-0048614 2020-04-22

Publications (1)

Publication Number Publication Date
WO2021215630A1 true WO2021215630A1 (en) 2021-10-28

Family

ID=78269451

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2021/001345 Ceased WO2021215630A1 (en) 2020-04-22 2021-02-02 Low-cost austenitic stainless steel having high strength and high formability, and method for manufacturing same

Country Status (6)

Country Link
US (1) US20230142021A1 (en)
EP (1) EP4119693A4 (en)
JP (1) JP7395769B2 (en)
KR (1) KR102385472B1 (en)
CN (1) CN115398022B (en)
WO (1) WO2021215630A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2025500865A (en) * 2021-12-16 2025-01-15 ポスコ カンパニー リミテッド Austenitic stainless steel and its manufacturing method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102463015B1 (en) * 2020-11-23 2022-11-03 주식회사 포스코 High-strength austenitic stainless steel with excellent hot workability

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20060075725A (en) * 2004-12-29 2006-07-04 주식회사 포스코 Work Hardening Low Nickel Austenitic Stainless Steel
KR100641577B1 (en) * 2005-04-19 2006-10-31 주식회사 포스코 High Manganese and Nitrogen Austenitic Stainless Steels
KR20080106200A (en) * 2006-12-27 2008-12-04 닛폰 스틸 앤드 스미킨 스테인레스 스틸 코포레이션 Stainless steel sheet for structural members with excellent shock absorption characteristics
JP2015206118A (en) * 2010-05-06 2015-11-19 オウトクンプ オサケイティオ ユルキネンＯｕｔｏｋｕｍｐｕ Ｏｙｊ Production method for low-nickel austenitic stainless steel and use of steel produced by the production method
KR101952818B1 (en) * 2017-09-25 2019-02-28 주식회사포스코 Low alloy steel sheet with high strength and ductility and method of manufacturing same

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5286310A (en) * 1992-10-13 1994-02-15 Allegheny Ludlum Corporation Low nickel, copper containing chromium-nickel-manganese-copper-nitrogen austenitic stainless steel
KR100545089B1 (en) * 2001-12-26 2006-01-24 주식회사 포스코 Hardened Austenitic Stainless Steel
KR20060025873A (en) * 2004-09-17 2006-03-22 주식회사 포스코 High Manganese High Nitrogen Austenitic Stainless Steel with Excellent Hot Workability and Cold Workability
CN101270455B (en) * 2007-03-23 2010-08-11 宝山钢铁股份有限公司 1000MPa grade nickel-saving type metastable austenite stainless steel
CN101724790B (en) * 2008-10-23 2012-12-19 宝山钢铁股份有限公司 Low-nickel austenitic stainless steel and manufacturing method thereof
JP6095619B2 (en) * 2014-08-19 2017-03-15 日新製鋼株式会社 Austenitic stainless steel sheet and metal gasket
KR101638007B1 (en) 2014-12-11 2016-07-13 한국기계연구원 High strength and high toughness austenite stainless steel with reduced nickel content
KR101903174B1 (en) 2016-12-13 2018-10-01 주식회사 포스코 Low alloy steel sheet with excellent strength and ductility
CN109112430A (en) * 2017-06-26 2019-01-01 宝钢不锈钢有限公司 A kind of low-cost high-strength low-nickel austenitic stainless steel and manufacturing method
CN109837470B (en) * 2017-11-29 2022-04-01 宝钢德盛不锈钢有限公司 High-strength nitrogen-containing economical austenitic stainless steel and manufacturing method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20060075725A (en) * 2004-12-29 2006-07-04 주식회사 포스코 Work Hardening Low Nickel Austenitic Stainless Steel
KR100641577B1 (en) * 2005-04-19 2006-10-31 주식회사 포스코 High Manganese and Nitrogen Austenitic Stainless Steels
KR20080106200A (en) * 2006-12-27 2008-12-04 닛폰 스틸 앤드 스미킨 스테인레스 스틸 코포레이션 Stainless steel sheet for structural members with excellent shock absorption characteristics
JP2015206118A (en) * 2010-05-06 2015-11-19 オウトクンプ オサケイティオ ユルキネンＯｕｔｏｋｕｍｐｕ Ｏｙｊ Production method for low-nickel austenitic stainless steel and use of steel produced by the production method
KR101952818B1 (en) * 2017-09-25 2019-02-28 주식회사포스코 Low alloy steel sheet with high strength and ductility and method of manufacturing same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4119693A4 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2025500865A (en) * 2021-12-16 2025-01-15 ポスコ カンパニー リミテッド Austenitic stainless steel and its manufacturing method
EP4431631A4 (en) * 2021-12-16 2025-10-22 Posco Co Ltd AUSTENITIC STAINLESS STEEL AND MANUFACTURING PROCESSES THEREFOR

Also Published As

Publication number Publication date
CN115398022B (en) 2023-11-28
JP2023522999A (en) 2023-06-01
EP4119693A4 (en) 2024-04-24
EP4119693A1 (en) 2023-01-18
CN115398022A (en) 2022-11-25
KR20210130426A (en) 2021-11-01
JP7395769B2 (en) 2023-12-11
KR102385472B1 (en) 2022-04-13
US20230142021A1 (en) 2023-05-11

Similar Documents

Publication Publication Date Title
WO2020130560A1 (en) Cold rolled steel sheet having excellent workability, hot-dip galvanized steel sheet, and manufacturing methods thereof
WO2009145563A2 (en) Ultra high strength steel sheet with an excellent heat treatment property for hot press forming, quenched member, and manufacturing method for same
WO2022050635A1 (en) Austenitic stainless steel and manufacturing method thereof
WO2020222394A1 (en) Hot-stamped part and manufacturing method therefor
WO2022124609A1 (en) High-strength hot-dip galvanized steel sheet with high ductility and excellent formability, and manufacturing method for same
WO2021117989A1 (en) Cold rolled steel sheet with ultra-high strength, and manufacturing method therefor
WO2017188654A1 (en) Ultrahigh-strength and high-ductility steel sheet having excellent yield ratio and manufacturing method therefor
WO2010074370A1 (en) High-strength elongation steel sheet, hot-rolled steel sheet, cold-rolled steel sheet, zinc-coated steel sheet, and method for manufacturing alloyed zinc-coated steel sheet
WO2022119253A1 (en) Ultra-high strength cold rolled steel sheet having excellent bendability, and method of manufacturing same
WO2015099222A1 (en) Hot-rolled steel plate having excellent welding property and burring property and method for manufacturing same
WO2017222159A1 (en) High-strength cold-rolled steel sheet with excellent workability and manufacturing method therefor
WO2022131504A1 (en) Austenitic stainless steel with improved high temperature softening resistance
WO2021215630A1 (en) Low-cost austenitic stainless steel having high strength and high formability, and method for manufacturing same
WO2021085800A1 (en) Austenitic stainless steel having increased yield ratio and manufacturing method thereof
WO2021125471A1 (en) Wire rod for ultra-high strength spring, steel wire and manufacturing method thereof
WO2021261884A1 (en) High-strength austenitic stainless steel with excellent productivity and cost reduction effect and method for producing same
WO2022045595A1 (en) Austenitic stainless steel with improved deep drawability
WO2021010599A2 (en) Austenitic stainless steel having improved strength, and method for manufacturing same
WO2011081236A1 (en) Quenched steel sheet having excellent hot press formability, and method for manufacturing same
WO2010074458A2 (en) High-strength cold rolled steel sheet having superior deep drawability and a high yield ratio, galvanized steel sheet using same, alloyed galvanized steel sheet, and method for manufacturing same
WO2020130614A2 (en) High strength hot-rolled steel sheet having excellent hole expansion ratio and manufacturing method for same
WO2023096453A1 (en) Ultra-high strength cold-rolled steel sheet having excellent elongation and manufacturing method thereof
WO2019039774A1 (en) Ferritic stainless steel having enhanced low-temperature impact toughness and method for producing same
WO2019009636A1 (en) Cold rolled steel sheet for flux-cored wire, and manufacturing method therefor
WO2021025248A1 (en) Ferritic stainless steel with improved high temperature creep resistance and manufacturing method therefor

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21793437

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2021793437

Country of ref document: EP

Effective date: 20221011

ENP Entry into the national phase

Ref document number: 2022564367

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE