CN109563601A - High tensile hot rolled steel sheet and its manufacturing method with low inhomogeneities and excellent surface quality - Google Patents
High tensile hot rolled steel sheet and its manufacturing method with low inhomogeneities and excellent surface quality Download PDFInfo
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- CN109563601A CN109563601A CN201780048797.4A CN201780048797A CN109563601A CN 109563601 A CN109563601 A CN 109563601A CN 201780048797 A CN201780048797 A CN 201780048797A CN 109563601 A CN109563601 A CN 109563601A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 128
- 239000010959 steel Substances 0.000 title claims abstract description 128
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 30
- 238000005096 rolling process Methods 0.000 claims abstract description 57
- 238000000034 method Methods 0.000 claims description 36
- 238000001816 cooling Methods 0.000 claims description 21
- 239000002244 precipitate Substances 0.000 claims description 19
- 229910000859 α-Fe Inorganic materials 0.000 claims description 17
- 238000009749 continuous casting Methods 0.000 claims description 16
- 229910052757 nitrogen Inorganic materials 0.000 claims description 16
- 229910052758 niobium Inorganic materials 0.000 claims description 15
- 238000005554 pickling Methods 0.000 claims description 15
- 239000000047 product Substances 0.000 claims description 15
- 239000002826 coolant Substances 0.000 claims description 13
- 229910052799 carbon Inorganic materials 0.000 claims description 12
- 239000012535 impurity Substances 0.000 claims description 12
- 230000008569 process Effects 0.000 claims description 12
- 229910001566 austenite Inorganic materials 0.000 claims description 11
- 229910001563 bainite Inorganic materials 0.000 claims description 10
- 239000013078 crystal Substances 0.000 claims description 10
- 230000005540 biological transmission Effects 0.000 claims description 9
- 229910052719 titanium Inorganic materials 0.000 claims description 9
- 229910052782 aluminium Inorganic materials 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- 239000008187 granular material Substances 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 6
- 229910052748 manganese Inorganic materials 0.000 claims description 6
- 229910052698 phosphorus Inorganic materials 0.000 claims description 6
- 229910052710 silicon Inorganic materials 0.000 claims description 6
- 229910000734 martensite Inorganic materials 0.000 claims description 5
- 229910052718 tin Inorganic materials 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims description 3
- 229910052750 molybdenum Inorganic materials 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 229910052745 lead Inorganic materials 0.000 claims 2
- 239000010955 niobium Substances 0.000 description 17
- 239000000463 material Substances 0.000 description 15
- 239000010936 titanium Substances 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 10
- 238000005516 engineering process Methods 0.000 description 10
- 239000011572 manganese Substances 0.000 description 10
- 239000011651 chromium Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 9
- 239000000203 mixture Substances 0.000 description 7
- 230000007547 defect Effects 0.000 description 6
- 238000001556 precipitation Methods 0.000 description 5
- 230000009466 transformation Effects 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 238000005266 casting Methods 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 3
- 238000000399 optical microscopy Methods 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000003321 amplification Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 230000001965 increasing effect Effects 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 230000001376 precipitating effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- 230000003746 surface roughness Effects 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 241000251468 Actinopterygii Species 0.000 description 1
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910001567 cementite Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000016507 interphase Effects 0.000 description 1
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
- B21B1/463—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a continuous process, i.e. the cast not being cut before rolling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
- B21B3/02—Rolling special iron alloys, e.g. stainless steel
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/04—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing
- B21B45/08—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing hydraulically
-
- 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
-
- 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
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
-
- 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
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- 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
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
-
- 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
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- 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
- C21D2211/005—Ferrite
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials 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 object of the present invention is to provide a kind of high tensile hot rolled steel sheet and its manufacturing methods, in order to overcome the problems, such as existing abbreviated system, by using endless rolling mode during continuous casting-Direct Rolling, the steel plate ensures the unique property (such as hole expansibility) of high reaming crimp steel, and at the same time significantly reducing the inhomogeneities in the width direction and length direction of the steel plate and having excellent surface quality.
Description
Technical field
This disclosure relates to a kind of high tensile hot rolled steel sheet with low inhomogeneities and excellent surface quality, Yi Jiyong
There is the method for the high tensile hot rolled steel sheet of low inhomogeneities and excellent surface quality in manufacture.
Background technique
In recent years, new steel making method has been attracted attention using the manufacturing method (abbreviated system) of sheet billet, and
Since the temperature deviation on the width and length direction of steel band in the method is small, this method, which is considered to have to manufacture, to be had
The potential ability of the phase transformation steel of low inhomogeneities.
Fig. 1 is the patent shown for producing the high-strength hot-rolled high reaming crimp steel that tensile strength grade is 590MPa
The figure of the abbreviated system of the relevant technologies disclosed in document 1.According to the existing method for using short route steel mill manufacture steel plate, make
The sheet billet (a) with a thickness of 50mm to 150mm (a) is produced with conticaster 10；Sheet billet is rolled by using roughing mill 20
With a thickness of given value or smaller batten；Batten is batched with the company of compensation in the coil box that 50 front of finishing mill is set
Speed difference between casting and rolling；And carry out finish rolling.Finishing mill 50 rolls batten to obtain and have expected thickness (3.0mm or more
Steel plate greatly), and it is using ROT (hereinafter referred to " runout table ") 60 that steel plate is cooling.Then, using coiling machine 70 to steel plate
It is batched.
It is however generally that there are problems that three when producing steel plate according to patent document 1.
Firstly, when being batched in coil box to the batten through roughing, the one of the roughing batten engaged with coil box
Partial temperature may drastically reduce, so that being difficult to remove descale from the part and deteriorating surface quality.
Secondly, being likely difficult to production final thickness by the abbreviated system of the relevant technologies is 3.0mm or smaller steel plate.
In other words, the abbreviated system of the relevant technologies is batch-type process, wherein batten is batched and then opened in coil box
Volume, and when producing one block of steel plate every time, these for carrying out batten batch and uncoiling.Therefore, it during finish rolling, is unable to fully protect
The linear transmission for demonstrate,proving steel plate and steadily transmission, and it is very high a possibility that Plate break, it makes it difficult to produce with a thickness of 3.0mm
Or smaller steel plate.
Third does not reheat sheet billet when supplying the sheet billet produced by conticaster to roughing mill.Cause
This, the surface temperature of sheet billet marginal portion sharply drops to 800 DEG C or lower level.In general, high-strength hot-rolled high reaming
Crimp steel plate includes a large amount of precipitate formation element such as Nb, V or Ti, therefore, if high-strength hot-rolled high reaming crimp steel
The temperature of the marginal portion of plate is low, then high-strength hot-rolled high reaming crimp steel plate due to high temperature ductility reduction and be highly prone to side
The influence of edge defect.
Therefore, it is necessary to develop a kind of manufacturing method that can overcome the above problem.
(patent document 1) South Korea patent application Patent Publication the 2012-0049992nd
Summary of the invention
Technical problem
The aspect of present disclosure can provide high tensile hot rolled steel sheet with excellent surface quality and for manufacturing
The method of high tensile hot rolled steel sheet, the high tensile hot rolled steel sheet are raw with endless rolling mode by continuous casting-Direct Rolling process
It produces to assign the inherent characteristic of high reaming crimp steel, such as the width of high hole expansibility and significantly reduced high tensile hot rolled steel sheet
The inhomogeneities in direction and length direction.
Above-mentioned aspect is not limited in terms of present disclosure.By being described below, those skilled in the art will be clear that geography
Solve the above-mentioned aspect and other aspects of present disclosure.
Technical solution
According to one aspect of the present disclosure, with the high tensile hot rolled steel sheet of low inhomogeneities and excellent surface quality
Can include in terms of % by weight: C:0.02% to 0.06%, Mn:1.0% to 2.0%, Si:0.1% to 0.3%, P:0.025%
Or smaller, S:0.01% or smaller, Cr:0.001% to 0.5%, Al:0.05% or smaller, Ti:0.001% to 0.1%, Nb:
0.001% to 0.03%, N:0.001% are to 0.012%, the iron (Fe) of surplus and inevitable impurity；
Wherein the microscopic structure of high tensile hot rolled steel sheet can based on area % comprising amount for 60% to 90% ferrite,
The bainite and amount that amount is 5% to 35% are 5% or smaller MA (martensite/austenite).
It is high-strength with low inhomogeneities and excellent surface quality for manufacturing according to the other side of present disclosure
The method for spending hot rolled steel plate may include following procedure:
Continuous casting steel is to obtain the sheet billet with a thickness of 50mm to 150mm, and molten steel % by weight meter includes: C:0.02% is extremely
0.06%, Mn:1.0% are to 2.0%, Si:0.1% to 0.3%, P:0.025% or smaller, S:0.01% or smaller, Cr:
0.001% to 0.5%, Al:0.05% or smaller, Ti:0.001% to 0.1%, Nb:0.001% to 0.03%, N:0.001%
To 0.012%, the iron (Fe) of surplus and inevitable impurity；
By the sheet billet formed by continuous casting heating until the marginal portion of sheet billet reaches 900 DEG C to 1000 DEG C of temperature
Degree；
Coolant is sprayed on heated sheet billet except descale under 150 bars or bigger of pressure；
To from the sheet billet progress roughing of descale is wherein removed to obtain batten；
Batten is sequentially passed through with 50 bars to 100 bars of pressure for coolant and is sprayed onto first row on batten and with 50 bars
Coolant is sprayed onto the secondary series on batten to remove descale from the batten to 200 bars of pressure；
Within the temperature range of Ar1 to Ar3, to from the batten progress finish rolling of descale is wherein removed to obtain hot-rolled steel
Plate；
Keep hot rolled steel plate cooling；And
It is batched within the temperature range of 300 DEG C to 500 DEG C to through cooling hot rolled steel plate,
Wherein the process is carried out continuously.
The above-mentioned aspect of present disclosure does not include all aspect or the feature of present disclosure.Implement from following exemplary
Other aspects or feature and effect of present disclosure are clearly understood that in the description of scheme.
Beneficial effect
According to present disclosure, continuous casting-Direct Rolling process is carried out to manufacture high strength rolled steel with endless rolling mode
Plate, the high tensile hot rolled steel sheet have 3.0mm or smaller thickness, high reaming crimp steel inherent characteristic such as hole expansibility,
Its significantly reduced width and inhomogeneities and high actual production yield on length direction.
In addition, be thin (with a thickness of 3.0mm or smaller) according to the high tensile hot rolled steel sheet that present disclosure manufactures, and
Since the marginal portion of high tensile hot rolled steel sheet and surface have less oxide skin, general hot rolled steel plate pickling can be passed through
Process is produced as pickling oiling (PO) product of high-quality.(thickness is greater than with can only manufacture thick hot rolled steel plate by it
Related abbreviated system 3.0mm) is different, the valence that present disclosure can be significantly improved with guaranteed price competitiveness and offer
Value.
Detailed description of the invention
Fig. 1 is to show the figure of the abbreviated system of the relevant technologies.
Fig. 2 is to show the continuous casting according to present disclosure-Direct Rolling process figure.
Fig. 3 is the image on the surface of the head portion of the PO coiled material of example 1.
Fig. 4 is the image on the surface of the head portion of the PO coiled material of comparative example 3.
Fig. 5 is the image of the microscopic structure in the example 1 shot using optical microscopy.
Fig. 6 is the image of the microscopic structure in the comparative example 3 shot using optical microscopy.
Fig. 7 is the image of the microscopic structure in the example 1 using transmission electron microscope (TEM) shooting.
Specific embodiment
The embodiment that will be described in present disclosure now.However, present disclosure can be with many different shapes
Formula illustrates, and should not be construed as limited to specific embodiment set forth herein.But these embodiments are provided so that this
Disclosure is thorough and complete, and sufficiently convey to those skilled in the art scope of the present disclosure.
It has been recognised by the inventors that, the abbreviated system of the relevant technologies may not be suitable for producing thin hot rolled steel plate
(with a thickness of 3.0mm or smaller), and may cause the problem of such as edge defect and surface quality deteriorate.Therefore, of the invention
People has made intensive studies to solve these problems.
As a result, the inventors discovered that, if using endless rolling mode and accurately during continuous casting-Direct Rolling
Manufacturing process is controlled, then can manufacture such high tensile hot rolled steel sheet: its inherent characteristic with high reaming crimp steel is for example
Hole expansibility, the inhomogeneities on the width and length direction being substantially reduced, high actual production yield and 3.0mm or smaller
Thickness.Based on the knowledge, the present inventor has invented the present invention.
Hereinafter, it will be described in detail according to one aspect of the present disclosure with low inhomogeneities and excellent surface product
The high tensile hot rolled steel sheet of matter.
According to one aspect of the present disclosure, with the high tensile hot rolled steel sheet of low inhomogeneities and excellent surface quality
The meter of % by weight includes: C:0.02% to 0.06%, Mn:1.0% to 2.0%, Si:0.1% to 0.3%, P:0.025% or more
It is small, S:0.01% or smaller, Cr:0.001% to 0.5%, Al:0.05% or smaller, Ti:0.001% to 0.1%, Nb:
0.001% to 0.03%, N:0.001% are to 0.012%, the Fe of surplus and other inevitable impurity, wherein high-strength hot
The microscopic structure of rolled steel plate based on area % comprising amount be 60% to 90% ferrite, measure be 5% to 35% bainite, with
And amount is 5% or smaller MA (martensite/austenite).
Firstly, will be described in the composition of alloy of the high tensile hot rolled steel sheet of present disclosure.In the following description, every kind
The content of element is provided with weight %.
C:0.02% to 0.06%
Carbon (C) is to form carbide or be dissolved in the element for increasing intensity in ferrite.
When the content of C is less than 0.02%, it may be difficult to obtain expected intensity in present disclosure.On the contrary, containing as C
When amount is greater than 0.06%, steel alloy is generated during high-speed continuous casting, leaks and formed in uneven thickness coagulate so as to cause molten steel
Gu shell, this leads to operating accident.It is therefore preferred that the content of C can be in the range of 0.02% to 0.06%.
Mn:1.0% to 2.0%
Manganese (Mn) is that ferrite is inhibited to form and improve stabilization of austenite, to promote to form low-temperature transformation phase and improve
The element of the intensity of steel.
When the content of Mn is less than 1.0%, it may be difficult to obtain expected intensity in present disclosure.However, when Mn's
When content is more than 2.0%, such as characteristic of solderability or hot rolling characteristic be may deteriorate.It is therefore preferred that the content of Mn can be
In the range of 1.0% to 2.0%.
Si:0.1% to 0.3%
Silicon (Si) is to inhibit higher content to strengthen to be formed with carbide, to improve the stability and steel of retained austenite
The element of the ductility of plate.
When the content of Si is less than 0.1%, it is difficult to fully ensure that said effect.However, the content as Si is greater than 0.3%
When, red oxidization skin may be formed on a surface of a steel sheet, and its trace is likely to remain on the surface of steel plate after pickling,
To reduce surface quality.It is therefore preferred that the content of Si can be in the range of 0.1% to 0.3%.
P:0.025% or smaller
Phosphorus (P) can be used as impurity and be segregated along crystal boundary and/or interphase boundary and cause embrittlement.It therefore, can containing P
Amount is adjusted to as low as possible, and preferably the content of P can be adjusted in 0.025% or smaller range.
S:0.01% or smaller
Sulphur (S) is a kind of impurity, it can along during MnS (non-metallic inclusion) and the solidification in continuous casting process
It is segregated in steel, so as to cause high temperature cracking.Therefore, the content of S can be adjusted to it is as low as possible, and can be preferably by S's
Content is adjusted in 0.01% or smaller range.
Cr:0.001% to 0.5%
Chromium (Cr) is to improve the element of the intensity of steel by improving harden ability.
When the content of Cr is less than 0.001%, said effect is insufficient.On the contrary, when the content of Cr is more than 0.5%, steel plate
Ductility may deteriorate.It is therefore preferred that the content of Cr can be in the range of 0.001% to 0.5%.
Al:0.05% or smaller
Aluminium (Al) may concentrate on making on surface of steel plate the platability of steel plate to deteriorate, but can inhibit the formation of carbide simultaneously
Therefore the ductility of steel plate is improved.In addition, aluminium (Al) can react with nitrogen (N) and can be used as AlN precipitation in steel, work as life
When producing sheet billet, slab may be caused to crack under the slab cooling condition that this precipitation occurs, to make slab or hot-rolled steel
The quality deterioration of plate.
Therefore, the content of Al can be adjusted to as low as possible, and the content of Al preferably can be adjusted to 0.05%
Or in smaller range.
Ti:0.001% to 0.1%
Titanium (Ti) is the element for the intensity to form precipitate and nitride and increase steel.
When the content of Ti is less than 0.001%, said effect is insufficient.On the contrary, when the content of Ti is greater than 0.1%, manufacture
Cost can increase, and ferritic ductility may be decreased.It is therefore preferred that the content of Ti can 0.001% to
In the range of 0.1%.
Nb:0.001% to 0.03%
Niobium (Nb) is the element to form carbide and austenite grain is therefore caused to refine at high temperature.In addition, Nb dissolves
In ferrite and increase intensity.
When the content of Nb is less than 0.001%, said effect is insufficient.On the contrary, when the content of Nb is greater than 0.03%, it can
NbC, (Ti, Nb) CN etc. can be excessively formed and cause by continuous casting formed slab high temperature or low temperature brittleness, so as to cause heat
The edge defect of rolled steel plate.It is therefore preferred that the content of Nb can be in the range of 0.001% to 0.03%.
N:0.001% to 0.012%
Nitrogen (N) is to keep austenite stable and form the element of nitride.
When the content of N is less than 0.001%, said effect is insufficient.On the contrary, when the content of N is greater than 0.012%, analysis
Strengthening out may react with precipitate formation element with N and be increased, but ductility may drastically reduce.
It is therefore preferred that the content of N can be in the range of 0.001% to 0.012%.
Another component of the high tensile hot rolled steel sheet of present disclosure is iron (Fe).However, can in high tensile hot rolled steel sheet
It can inevitably include the impurity of raw material or manufacturing environment, and possibly can not be by these impurity from high tensile hot rolled steel sheet
It removes.These impurity are well known for the those of ordinary skill in manufacturing industry, therefore will not give in this disclosure
The specific descriptions of these impurity out.
In this case, other than above-mentioned alloying element, high tensile hot rolled steel sheet can also include Cu, Ni, Mo, Sn
It is used as incidental element at least one of Pb, and its total amount can be 0.2 weight % or smaller.
Such incidental element is to be used as the impurity element included in steelmaking process in the waste material of raw material.If its total amount
More than 0.2%, then face checking may occur in sheet billet, and the surface quality of hot rolled steel plate may deteriorate.
It, can be in the range of 0.10 to 0.24 by the Ceq that the following Expression 1 indicates other than meeting above-mentioned composition of alloy.
Formula 1:Ceq=C+Si/30+Mn/20+2P+3S
(in above formula 1, each symbol of element refers to content of each element in terms of weight percent (wt%))
Above formula 1 is for ensuring that the component relational expression of the solderability of steel plate.It in this disclosure, can be by Ceq tune
Save in the range of 0.10 to 0.24 to guarantee high solderability and assign mechanical property expected from welding section.
When Ceq is less than 0.10, due to low harden ability, it may be difficult to proof strength.On the contrary, when Ceq is greater than 0.24,
Solderability may deteriorate, and therefore the physical characteristic of welding section may deteriorate.
Hereinafter, it will be described in the microscopic structure of the hot rolled steel plate of present disclosure.
The microscopic structure of the hot rolled steel plate of present disclosure is based on area % comprising measuring the ferrite for 60% to 90%, amount
It is 5% or smaller MA (martensite/austenite) for 5% to 35% bainite and amount.
When ferritic score is greater than 90%, it is difficult to guarantee expected intensity；When ferritic score is less than 60%,
Since the score of bainite and MA increase, therefore, it is difficult to guarantee hole expansibility.
Bainite simultaneously effective ensures intensity and hole expansibility.When the score of bainite is less than 5%, said effect is not filled
Point；When the score of bainite is greater than 35%, due to excessively high intensity, it may be difficult to guarantee hole expansibility.
In addition, the score of MA is preferably 0% to ensure high hole expansibility.However, due to MA effectively proof strength,
The score of MA preferably can be adjusted to 5% or smaller.
It in this case, can be at 5 μm or smaller with the average-size of the ferrite crystal grain of equivalent diameter measurement
In range.
This is in order to obtain the ferrite with fine grain, with proof strength and hole expansibility simultaneously.If ferrite crystal grain
Size be more than 5 μm, then be likely difficult to ensure expected intensity and hole expansibility.
In addition, the hot rolled steel plate of present disclosure may include (Ti, Nb) (C, N) precipitate, surveyed with equivalent diameter
The average-size of amount is in 30nm or smaller range, and the granule number of (Ti, Nb) (C, N) precipitate can be in 5/μm2
To 30/μm2In the range of.Herein, (Ti, Nb) (C, N) precipitate may include TiC, NbC, TiN, NbN and its compound precipitation
Object.
When the size of precipitate is more than 30nm, it may be difficult to effectively proof strength.In addition, working as the granule number of precipitate
Less than 5/μm2When, it may be difficult to guarantee expected intensity.On the contrary, the granule number when precipitate is greater than 30/μm2When, intensity
It can increase so that elongation percentage and hole expansibility deteriorate, and may crack during the processing.
In addition, the thickness of the hot rolled steel plate of present disclosure can be 3.0mm or smaller.
It is different from the existing abbreviated system for only allowing to produce thick hot-finished material (thickness is greater than 3.0mm), in the disclosure
The manufacturing method proposed in appearance allows to produce with a thickness of 3.0mm or smaller hot-finished material.
The hot rolled steel plate of present disclosure can have 590Mpa or bigger tensile strength, 80% or bigger hole expansibility
With the tensile strength deviation of 10MPa or more a small range.
Hereinafter, will according to the other side of present disclosure be described in detail be used for manufacture have low inhomogeneities and
The method of the high tensile hot rolled steel sheet of excellent surface quality.
It is high-strength with low inhomogeneities and excellent surface quality for manufacturing according to the other side of present disclosure
The method of hot rolled steel plate is spent the following steps are included: carrying out continuous casting to the molten steel with above-mentioned composition of alloy to obtain with a thickness of 50mm
To the sheet billet of 150mm；By the sheet billet formed by continuous casting heating until the marginal portion of sheet billet reaches 900 DEG C to 1000
DEG C temperature；Coolant is sprayed on heated sheet billet except descale with 150 bars or bigger of pressure；To from
Wherein except the sheet billet of descale carries out roughing to obtain batten；Sequentially passing through batten will with 50 bars to 100 bars of pressure
First row that coolant is sprayed on batten and with 50 bars to 200 bars of pressure by coolant be sprayed onto the secondary series on batten with
Descale is removed from the batten；Within the temperature range of Ar1 to Ar3, to from the batten progress for wherein removing descale
Finish rolling is to obtain hot rolled steel plate；Hot rolled steel plate is cooling；And to through cooling heat within the temperature range of 300 DEG C to 500 DEG C
Rolled steel plate is batched, wherein the process is carried out continuously.
Fig. 2 shows continuous casting-Direct Rollings of the present disclosure of the abbreviated system for overcoming the problems, such as the relevant technologies
One example of process.The sheet billet (a) with a thickness of 50mm to 150mm is manufactured using conticaster 100, and in heater 200
Slab is heated up to the marginal portion of slab reaches 900 DEG C or higher to reduce edge defect sensibility and improve product in addition
Matter.Further, since without placing coil box between roughing mill 400 and finishing mill 600, thus can with continuous rolling steel plate, from
And a possibility that guaranteeing the abundant steady transmission of steel plate and reducing fracture.Thus it is possible to produce thin with a thickness of 3.0mm or smaller
Material.Roughing descaler (hereinafter referred to RSB) 300 is arranged in front of roughing mill 400, finish rolling descaler
(hereinafter referred to " FSB ") 500 is arranged in front of finishing mill 600.Therefore, surface scale can be easily removed, and
If carrying out pickling to hot rolled steel plate during later, the pickling oiling (PO) with excellent surface quality can be obtained
Product.In addition, mill speed can carry out finish rolling to one block of steel plate when carrying out finish rolling during continuous casting-Direct Rolling
Shi Bianhua 5% or smaller, so as to realize constant temperature constant speed rolling and significantly reduce in the width direction and length direction of steel plate
Temperature deviation.Therefore, it can be realized accurate cooling control in ROT (hereinafter referred to runout table) 600, so as to
Produce the high-strength hot-rolled high reaming crimp steel plate with low inhomogeneities.
Hereinafter, it will be described in each process.
Continuous casting
Continuous casting is carried out to obtain the sheet billet with a thickness of 50mm to 150mm to the molten steel with above-mentioned composition of alloy.
At this point, the speed of continuous casting can be 5.0mpm or bigger.
Casting speed is set as 5.0mpm or bigger reason is, since continuous casting and rolling are in this disclosure
It is carried out continuously, therefore it is required that casting speed is greater than a certain threshold value to obtain expected rolling temperature.
Heating
By the sheet billet formed by continuous casting heating until the temperature of the marginal portion of sheet billet reaches 900 DEG C to 1000 DEG C
Range.
If the temperature of marginal portion is lower than 900 DEG C, Nb (C, N) and AlN precipitate are largely formed, so that high temperature be made to prolong
Property reduces and dramatically increases edge crack sensibility.On the contrary, if the temperature of marginal portion is higher than 1000 DEG C, in sheet billet
The temperature of center portion point becomes too high, it is thus possible to a large amount of undaform oxide skin is formed, to keep the surface quality after pickling bad
Change.
Remove sheet billet oxide skin
Coolant is sprayed on heated sheet billet except descale with 150 bars or bigger of pressure.For example, can
To pass through roughing descaler (RSB) nozzle with 150 bars or bigger of pressure spray temperature as 40 DEG C or lower cooling
Agent is to be decreased to 300 μm or smaller for the thickness of surface scale.
If spray pressure may remain a large amount of oxide skins on sheet billet surface less than 150 bars, and therefore after pickling
Surface quality may be poor.
Roughing
The sheet billet except descale is set to be subjected to roughing to obtain batten.
Allow the thickness of batten for 10mm to 40mm at this point it is possible to carry out roughing.Roughing can preferably be passed through by item
The thickness of plate is adjusted in the range of 10mm to 40mm, to obtain with a thickness of the final hot rolled steel plate of 3.0mm or smaller.
Remove batten oxide skin
By sequentially pass through batten with 50 bars to 100 bars of pressure by coolant be sprayed onto first row on batten and with
Coolant is sprayed onto the secondary series on batten by 50 bars to 200 bars of pressure, and descale is removed from batten.For example, making item
Plate is subjected to before finish rolling, first jet column and the second spray by using finish rolling descaler (hereinafter referred to as " FSB ") 500
The thickness of the surface scale of batten, can be decreased to 50 μm or smaller thickness by mouth column.
If the pressure of first jet column and second nozzle column less than 50 bars, may be unable to fully remove descale, from
And a large amount of spindle oxide skin and fish scale type oxide skin may be formed after finish rolling, the surface quality after leading to pickling is poor.Phase
Instead, if the pressure of first jet column is more than 100 bars or second nozzle, the pressure that arranges is more than 200 bars, and final rolling temperature becomes
It is too low to obtain effective austenite score, and therefore, it is difficult to obtain expected tensile strength.
It is difficult to sufficiently remove descale using only single-row nozzle, and is therefore likely to form spindle oxide skin during finish rolling
(it is fatal product defects).Therefore, as described above, removing deoxidation using both first jet column and second nozzle column
Skin.
Finish rolling
To from the batten progress finish rolling of descale is wherein removed to obtain hot-rolled steel within the temperature range of Ar1 to Ar3
Plate.That is, carrying out two-phase (austenite and ferrite) rolling between Ar1 and Ar3 transformation temperature.
In the related art, abbreviated system just above Ar3 at a temperature of carry out.However, according to present disclosure,
The precipitate of balloon score is formed during finish rolling, therefore the score of the thin precipitate formed at low temperature is low, leads to thin precipitate
Precipitating reinforcing effect reduce.Therefore, zerolling is carried out within the temperature range of Ar1 to Ar3 to reduce the size of crystal grain, from
And the strengthening effect of fine grain is improved, to compensate the reduction of precipitating reinforcing effect by the strengthening effect for improving fine grain.
That is, although largely forming the precipitate of strain inducing during finish rolling and therefore making to be precipitated at low temperature
The amount of alloying element is reduced, but can improve intensity by crystal grain refinement by carrying out finish rolling at low temperature.
In the abbreviated system of the relevant technologies, if final rolling temperature is low, the deterioration of rolling workpiece transmission characteristic.However,
During continuous casting-Direct Rolling of present disclosure, constant temperature constant speed rolling is carried out, to realize zerolling without all
The operational issue deteriorated such as rolling workpiece transmission characteristic.
In such a case, it is possible to so that workpiece transmission speed within the scope of 200mpm to 600mpm, and hot-rolled steel
Plate carries out finish rolling with a thickness of 3.0mm or smaller mode.
It cools down and batches
After hot rolled steel plate is cooling, hot rolled steel plate is batched within the temperature range of 300 DEG C to 500 DEG C.
If coiling temperature is lower than 300 DEG C, it is likely that form martensite.If coiling temperature is higher than 500 DEG C, very may be used
Pearlite can be formed, and is therefore likely difficult to obtain expected material property.
At this point, cooling can proceed to T by air-coolingFin- 300 DEG C to TFin- 50 DEG C of cooling end temperature, so
Coiling temperature is reached by using light cold bed (light cooling bank) afterwards.TFinRefer to the end temperature of finish rolling.
Hot rolled steel plate air is cooled to TFin- 300 DEG C to TFin- 50 DEG C cooling the reason of terminating temperature is to promote
Ferrite transformation.If the cooling temperature that terminates is lower than TFinIt -300 DEG C, then may a possibility that the precipitation of carbide such as cementite
Increase, and since the score of austenite is low, the possible less generation of bainitic transformation, so that it is special to obtain expected material
Property.If the cooling temperature that terminates is higher than TFin- 50 DEG C, then ferritic score may be low, and may excessively promote bainite phase
Become, makes it difficult to obtain expected hole expansibility.
Since according to present disclosure, process is carried out continuously, therefore can be light by being used after air is cooling
Cold bed, which is cooled down, is adjusted to coiling temperature in above range.
In addition, this method can also include carrying out pickling to the hot rolled steel plate through batching to obtain pickling oiling (PO) production
Product.
In this disclosure, by removing the process of descale from sheet billet and from batten except the mistake of descale
Journey, oxide skin are sufficiently removed, therefore the PO (acid with excellent surface quality can also be obtained even if by general pickling processes
Washcoated oil) product.Therefore, it can use in this disclosure commonly used in being carried out to hot rolled steel plate at any pickling of pickling
Reason is without limiting.
Hereinafter, present disclosure will be more specifically described by embodiment.However, following embodiment only should be with description
Property meaning considers, rather than the purpose for limitation.Scope of the present disclosure being defined by the following claims, and can be with
Reasonably therefrom modifies and change.
Invention embodiment
(embodiment)
Prepare the molten steel with composition shown in the following table 1.
In example 1 to 3 and comparative example 1 and 2, under the manufacturing condition shown in table 2, directly rolled by continuous casting-
Process processed is with endless rolling mode of manufacture with a thickness of the hot rolled steel plate of 2.0mm.In addition, the Ar3 temperature in table 2 is using business heat
The value that machine software JmatPro V-8 is calculated.
In comparative example 3 and the relevant technologies embodiment, under the manufacturing condition shown in table 2, pass through the short of the relevant technologies
The hot rolled steel plate that flow process is produced in batch mode with a thickness of 3.2mm.
Pickling is carried out to obtain PO product to hot rolled steel plate produced, and measures tensile strength, the unevenness of each PO product
Even property, hole expansibility and surface quality, as shown in table 3 below.
It is surveyed using the JIS No.5 sample obtained at 1/4 width position (w/4) on the direction perpendicular to rolling direction
The tensile strength and hole expansibility (stretch flangeability) of each PO product are measured, and by measuring from the length and width direction of coiled material
Tensile strength values maximum value in subtract the minimum value of tensile strength values to measure the inhomogeneities of each PO product.Pass through punching press
The hole that diameter is 10.8mm is formed, cone is upwardly into hole, and is stood before cracking in the circumferential section of expanded bore
It is calculated as a percentage the ratio between initial diameter (10.8mm) and expansion diameter to measure the hole expansibility of each PO product.
The surface quality of every kind of PO product is assessed in head portion, middle section and tail portion using following standard.
Head portion: from coiled material head to the position 100m
Middle section: coiled material center ± 50m
Tail portion: from coiled material tail portion to the position 100m
Zero: average surface roughness is 3 μm or smaller, and the average deviation of glossiness is 20% or smaller
X: average surface roughness is greater than 3 μm, and glossiness average deviation is greater than 20%
[table 1]
[table 2]
[table 3]
In the example of all conditions proposed in meeting present disclosure, expected tensile strength is obtained
(590MPa grade) and hole expansibility (80% or bigger), and the surface quality of PO product is in all head portions, middle section
Be also all satisfactory in tail portion.
In addition, inhomogeneities (Δ TS, MPa) is 10MPa or smaller in example, to comparative example 3 and the related skill of use
It is to improve that the relevant technologies embodiment of the abbreviated system of art, which is compared,.
In the comparative example 1 to 3 of the RSB or FSB pressure proposed in being unsatisfactory for present disclosure, surface quality is poor.
Fig. 3 is the image on the head portion surface of the PO coiled material of example 1 (endless rolling mode), and Fig. 4 is comparative example 3
The image on the head portion surface of the PO coiled material of (batch mode).These the results show that surface quality with endless rolling mode
It is satisfactory in the example 1 produced, but is poor in the comparative example 3 produced in batch mode.With
The poor quality of the head portion of the PO coiled material of batch mode production, the reason is that being carried out in coil box to batten during hot rolling
It batches, and therefore reduces temperature, so as to cause being difficult to except descale.Therefore, the defect part average out to 50m of each coiled material
To 100m, the average value of actual yield less than 85%, this with by continuous casting-Direct Rolling process with endless rolling mode of manufacture steel
It is low-down that the case where plate (actual yield=98%), which is compared,.Therefore, it is necessary to be rolled during continuous casting-Direct Rolling with without a head
Molding formula is produced to produce the thin 590MPa grade high-strength improved in terms of inhomogeneities, surface quality and actual yield
Hot rolled steel plate.
Fig. 5 is shown in which in the example 1 (endless rolling mode) that final rolling temperature is 752 DEG C (being equal to or less than Ar3)
Microscopic structure, Fig. 6 is shown in which micro- group in the comparative example 3 (batch mode) that final rolling temperature is 857 DEG C (be greater than Ar3)
It knits.In microscopic structure, white is ferrite, and black is bainite or MA.
The size of ferrite crystal grain in example 1 is 2.65 μm, and the size of the ferrite crystal grain in comparative example 3 is 5.1 μ
m.Microstructure image is obtained from ten random sites under 1000 times of amplification factor by using optical microscopy to measure
The size of crystal grain measures average grain size by using Image Pro Plus software with equivalent diameter.These results
Display is the refinement and therefore that rolling in Ar3 or lower endless rolling mode promotes ferrite crystal grain in final rolling temperature
Promote low inhomogeneities and high hole expansibility.
Fig. 7 is the image of the microscopic structure in the example 1 obtained by transmission electron microscope (TEM).
Find out that precipitate for example thin (Ti, Nb) (C, N) is evenly distributed in ferrite matrix.The average-size of precipitate
For 17nm, and the average grain number of precipitate is 16/μm2.Herein, the number of composition granule is precipitated in following measurement: passing through carbon
Complex method prepares sample, and 1 μ is measured on the microstructure image of the sample shot under 50000 times of amplification factor using TEM
The number of precipitation composition granule during m × 1 μm is rectangular, and calculate the average value of these numbers measured in 50 random sites.
Although embodiment has been illustrated and described above, it will be clear to those skilled in the art that
In the case where not departing from the scope of the invention being defined by the following claims, modifications and changes can be made.
(description of symbols)
10: conticaster 20: roughing mill
30: heating unit 40: coil box
50: finishing mill 60: runout table
70: coiling machine
A: slab b: coiled material
100: conticaster 200: heater
300:RSB (roughing descaler)
400: roughing mill
500:FSB (finish rolling descaler)
600: finishing mill 700: runout table
800: high-speed shearing machine 900: coiling machine
Claims (15)
1. a kind of high tensile hot rolled steel sheet with low inhomogeneities and excellent surface quality, the high tensile hot rolled steel sheet is by weight
Amount % meter includes: C:0.02% to 0.06%, Mn:1.0% to 2.0%, Si:0.1% to 0.3%, P:0.025% or smaller,
S:0.01% or smaller, Cr:0.001% are to 0.5%, Al:0.05% or smaller, Ti:0.001% to 0.1%, Nb:0.001%
To 0.03%, N:0.001% to 0.012% and the iron (Fe) and inevitable impurity of surplus,
Wherein the microscopic structure of the high tensile hot rolled steel sheet is comprising measuring the ferrite for being 60% to 90%, measuring based on area %
5% to 35% bainite and amount is 5% or smaller MA (martensite/austenite).
2. high tensile hot rolled steel sheet according to claim 1, wherein the high tensile hot rolled steel sheet includes to deposit member as even
At least one of Cu, Ni, Mo, Sn and Pb of element, and the total amount of the incidental element is 0.2 weight % or smaller.
3. high tensile hot rolled steel sheet according to claim 1, wherein the Ceq of the high tensile hot rolled steel sheet indicated as follows
In the range of 0.10 to 0.24,
Ceq=C+Si/30+Mn/20+2P+3S
Wherein each symbol of element refers to content of each element in terms of weight %.
4. high tensile hot rolled steel sheet according to claim 1, wherein the ferritic crystal grain is surveyed with equivalent diameter
The average-size of amount is 5 μm or smaller.
5. high tensile hot rolled steel sheet according to claim 1, wherein the hot rolled steel plate is precipitated comprising (Ti, Nb) (C, N)
Object, the average-size with equivalent diameter measurement of (Ti, the Nb) (C, N) precipitate is in 30nm or smaller range, institute
The granule number of (Ti, Nb) (C, N) precipitate is stated in 5/μm2To 30/μm2In the range of.
6. high tensile hot rolled steel sheet according to claim 1, wherein the high tensile hot rolled steel sheet with a thickness of 3.0mm or
It is smaller.
7. high tensile hot rolled steel sheet according to claim 1, wherein the tensile strength of the high tensile hot rolled steel sheet is
590MPa or bigger, hole expansibility is 80% or bigger, and the deviation of tensile strength is in 10MPa or smaller range.
8. a kind of method for manufacturing the high tensile hot rolled steel sheet with low inhomogeneities and excellent surface quality, the method
Including following procedure:
Continuous casting is carried out to molten steel to obtain the sheet billet with a thickness of 50mm to 150mm, molten steel % by weight meter includes: C:
0.02% to 0.06%, Mn:1.0% are to 2.0%, Si:0.1% to 0.3%, P:0.025% or smaller, S:0.01% or more
It is small, Cr:0.001% to 0.5%, Al:0.05% or smaller, Ti:0.001% to 0.1%, Nb:0.001% to 0.03%, N:
0.001% to 0.012% and surplus iron (Fe) and inevitable impurity,
By the sheet billet formed by the continuous casting heating until the marginal portion of the sheet billet reaches 900 DEG C to 1000
DEG C temperature；
Coolant is sprayed on heated sheet billet except descale with 150 bars or bigger of pressure；
To from the sheet billet progress roughing of descale is wherein removed to obtain batten；
Sequentially pass through the batten with 50 bars to 100 bars of pressure by coolant be sprayed onto first row on the batten and with
The secondary series that coolant is sprayed on the batten by 50 bars to 200 bars of pressure from the batten to remove descale；
Within the temperature range of Ar1 to Ar3, to from the batten progress finish rolling of descale is wherein removed to obtain hot-rolled steel
Plate；
Keep the hot rolled steel plate cooling；And
It is batched within the temperature range of 300 DEG C to 500 DEG C to through cooling hot rolled steel plate,
Wherein the process is carried out continuously.
9. according to the method described in claim 8, wherein the steel ladle is containing in Cu, Ni, Mo, Sn and Pb as incidental element
At least one, and the total amount of the incidental element be 0.2 weight % or smaller.
10. according to the method described in claim 8, wherein range of the Ceq of the molten steel indicated as follows 0.10 to 0.24
It is interior,
Ceq=C+Si/30+Mn/20+2P+3S
Wherein each symbol of element refers to content of each element in terms of weight %.
11. according to the method described in claim 8, wherein carrying out the continuous casting with the speed of 5.0mpm or bigger.
12. according to the method described in claim 8, wherein carry out the roughing make the batten with a thickness of 10mm extremely
40mm。
13. according to the method described in claim 8, wherein with the plate transmission speed of 200mpm to 600mpm carry out the finish rolling with
It obtains with a thickness of the 3.0mm or smaller hot rolled steel plate.
14. according to the method described in claim 8, wherein the cooling by air-cooling proceeds to TFin- 300 DEG C extremely
TFin- 50 DEG C of cooling end temperature, then reaches coiling temperature by using light cold bed, wherein TFinRefer to that finish rolling terminates temperature
Degree.
15. according to the method described in claim 8, further including carrying out pickling to the hot rolled steel plate through batching to obtain PO product.
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| KR10-2016-0101132 | 2016-08-09 | ||
| KR1020160101132A KR101797383B1 (en) | 2016-08-09 | 2016-08-09 | High strength hot rolled steel sheet having low deviation of mechanical property and excellent surface quality and method for manufacturing the same |
| PCT/KR2017/008640 WO2018030790A1 (en) | 2016-08-09 | 2017-08-09 | High-strength hot rolled steel sheet having low inhomogeneity and excellent surface quality, and manufacturing method therefor |
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| CN113834828A (en) * | 2020-06-08 | 2021-12-24 | 东芝三菱电机产业系统株式会社 | Product quality analysis support system |
| CN114641587A (en) * | 2019-12-02 | 2022-06-17 | Posco公司 | Thick composite structure steel having excellent durability and method for producing same |
| CN116083795A (en) * | 2022-12-23 | 2023-05-09 | 本钢板材股份有限公司 | A hot-rolled high-hole expansion steel with high R value and its production method |
| CN120190209A (en) * | 2025-05-23 | 2025-06-24 | 华北理工大学 | Free-cutting steel and hot rolling method |
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| KR102109271B1 (en) * | 2018-10-01 | 2020-05-11 | 주식회사 포스코 | Ultra high strength hot rolled steel sheet having excellent surface qualities and low mechanical properties deviation and method of manufacturing the same |
| KR102643337B1 (en) * | 2019-07-10 | 2024-03-08 | 닛폰세이테츠 가부시키가이샤 | high strength steel plate |
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| CN116145038B (en) * | 2023-02-22 | 2025-01-14 | 湖南华菱涟源钢铁有限公司 | Hot rolled high-strength steel with uniform thickness and preparation method and application thereof |
| CN118904923B (en) * | 2024-08-27 | 2025-12-05 | 阳春新钢铁有限责任公司 | A control method for a high-efficiency water tank |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6488790B1 (en) * | 2001-01-22 | 2002-12-03 | International Steel Group Inc. | Method of making a high-strength low-alloy hot rolled steel |
| JP2005307339A (en) * | 2004-03-22 | 2005-11-04 | Jfe Steel Kk | High-tensile hot-rolled steel sheet with excellent strength-ductility balance and method for producing the same |
| CN101883875A (en) * | 2007-12-04 | 2010-11-10 | Posco公司 | High-strength steel plate having excellent low-temperature toughness and method of manufacturing the same |
| JP2011241456A (en) * | 2010-05-20 | 2011-12-01 | Sumitomo Metal Ind Ltd | Hot-dip-plated hot-rolled steel sheet and method of manufacturing the same |
| CN103210105A (en) * | 2010-11-12 | 2013-07-17 | 杰富意钢铁株式会社 | High-strength hot-dip galvanized steel sheet having excellent uniform elongation and plating properties, and method for manufacturing same |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5735663A (en) * | 1980-08-11 | 1982-02-26 | Kobe Steel Ltd | Hot rolled steel plate for rim of wheel |
| JP2000212687A (en) * | 1999-01-20 | 2000-08-02 | Nisshin Steel Co Ltd | High tensile strength hot rolled steel plate excellent in material uniformity and hole expansibility and its production |
| US10071416B2 (en) * | 2005-10-20 | 2018-09-11 | Nucor Corporation | High strength thin cast strip product and method for making the same |
| KR101245701B1 (en) * | 2010-11-15 | 2013-04-01 | 주식회사 포스코 | METHOD FOR MANUFACTURING TENSILE STRENGTH 590MPa CLASS HOT ROLLED DP STEEL WITH EXCELLENT WORKABILITY AND VARIATION OF MECHANICAL PROPERTY |
| KR101271985B1 (en) * | 2010-12-27 | 2013-06-05 | 주식회사 포스코 | Method for Treating Surface of Hot strip |
| KR101531778B1 (en) * | 2011-03-18 | 2015-06-25 | 신닛테츠스미킨 카부시키카이샤 | Hot-rolled steel sheet exhibiting exceptional press-molding properties and method for manufacturing same |
| KR101510272B1 (en) * | 2012-12-27 | 2015-04-08 | 주식회사 포스코 | Method for manufacturing hot rolled steel plate and hot rolled steel sheet |
| CN103526116B (en) * | 2013-10-08 | 2015-07-08 | 武汉钢铁(集团)公司 | Ferrite-bainite steel having tensile strength reaching 590MPa level and having high hole expanding performance, and production method thereof |
| KR20150076994A (en) * | 2013-12-27 | 2015-07-07 | 현대제철 주식회사 | Steel product for building and method of manufacturing the same |
| KR20160025185A (en) * | 2014-08-27 | 2016-03-08 | 현대제철 주식회사 | High strength plated hot-rolled steel sheet and method of manufacturing the same |
-
2016
- 2016-08-09 KR KR1020160101132A patent/KR101797383B1/en active Active
-
2017
- 2017-08-09 CN CN201780048797.4A patent/CN109563601A/en not_active Withdrawn
- 2017-08-09 JP JP2019505026A patent/JP2019527774A/en active Pending
- 2017-08-09 WO PCT/KR2017/008640 patent/WO2018030790A1/en not_active Ceased
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6488790B1 (en) * | 2001-01-22 | 2002-12-03 | International Steel Group Inc. | Method of making a high-strength low-alloy hot rolled steel |
| JP2005307339A (en) * | 2004-03-22 | 2005-11-04 | Jfe Steel Kk | High-tensile hot-rolled steel sheet with excellent strength-ductility balance and method for producing the same |
| CN101883875A (en) * | 2007-12-04 | 2010-11-10 | Posco公司 | High-strength steel plate having excellent low-temperature toughness and method of manufacturing the same |
| JP2011241456A (en) * | 2010-05-20 | 2011-12-01 | Sumitomo Metal Ind Ltd | Hot-dip-plated hot-rolled steel sheet and method of manufacturing the same |
| CN103210105A (en) * | 2010-11-12 | 2013-07-17 | 杰富意钢铁株式会社 | High-strength hot-dip galvanized steel sheet having excellent uniform elongation and plating properties, and method for manufacturing same |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110090861A (en) * | 2019-05-21 | 2019-08-06 | 东北大学 | A kind of efficient endless rolling method of simple shape |
| WO2021052434A1 (en) * | 2019-09-19 | 2021-03-25 | 宝山钢铁股份有限公司 | Nb microalloyed high strength high hole expansion steel and production method therefor |
| CN114641587A (en) * | 2019-12-02 | 2022-06-17 | Posco公司 | Thick composite structure steel having excellent durability and method for producing same |
| CN114641587B (en) * | 2019-12-02 | 2023-08-25 | Posco公司 | Thick composite structural steel excellent in durability and method for producing same |
| US12435400B2 (en) | 2019-12-02 | 2025-10-07 | Posco | Thick composite-phase steel having excellent durability and manufacturing method therefor |
| CN113834828A (en) * | 2020-06-08 | 2021-12-24 | 东芝三菱电机产业系统株式会社 | Product quality analysis support system |
| CN116083795A (en) * | 2022-12-23 | 2023-05-09 | 本钢板材股份有限公司 | A hot-rolled high-hole expansion steel with high R value and its production method |
| CN120190209A (en) * | 2025-05-23 | 2025-06-24 | 华北理工大学 | Free-cutting steel and hot rolling method |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2018030790A1 (en) | 2018-02-15 |
| JP2019527774A (en) | 2019-10-03 |
| KR101797383B1 (en) | 2017-11-13 |
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