TW200815613A - Duplex stainless steel - Google Patents

Abstract

The invention relates to a duplex stainless steel, the composition of which consists of, in % by weight: C ≤ 0.05%; 21% ≤ Cr ≤ 25%; 1% ≤ Ni ≤ 2.95%; 0.16% ≤ N ≤ 0.28%; Mn ≤ 2.0%; Mo+W/2 ≤ 0.50%; Mo ≤ 0.45%; W ≤ 0.15%; Si ≤ 1.4%; Al ≤ 0.05%; 0.11% ≤ Cu ≤ 0.50%; S ≤ 0.010%; P ≤ 0.040%; Co ≤ 0.5%; REM ≤ 0.1%; V ≤ 0.5%; Ti ≤ 0.1%; Nb ≤ 0.3%; Mg ≤ 0.1%, the balance being iron and impurities resulting from the smelting, and the microstructure consisting of austenite and 35 to 65% ferrite by volume, the composition furthermore satisfying the following relationships: 40 ≤ IF ≤ 70, where IF=6x(%Cr+1.32x%Mo+1.27x%Si)-10x(%Ni+4x%C+16.15x%N+0.5x%Cu+0.4x%Mn)-6.17 and ILCR ≥ 30.5 where ILCR=%Cr+3.3x%Mo+16x%N+2.6x%Ni-0.7x%Mn, and also to a process for manufacturing plate, strip, coil, bar, rod, wire, sections, forgings and castings made of this steel.

Description

200815613 IX. INSTRUCTIONS: [Technical field to which the invention pertains] The present invention relates to a double-grain steel, and more particularly to a method for manufacturing a material manufacturing device (chemical, petrochemical cognac paper, and the like without any limitation thereto) Structural components for offshore manufacturing or energy manufacturing equipment, and also for methods of making panels, strips, rods, sticks, wires or blocks from such steel. [Prior Art] - Generally speaking, 'in many applications', as in the aforementioned industries or in the agricultural food industry, including self-forming sticks or wires (welded grids, etc.), block pieces (stress applicators·· Etc.), shaft dry.. and other parts, this steel can be used as a substitute for 3〇 stainless steel. It can also make castings and forgings. For this purpose, stainless steel grades of the Type 304 and Type 304L have been known which, in the annealed state, substantially have a Worthite iron microstructure. In the cold worked state, they may further contain a variable proportion of granita iron. However, these steels include a large amount of added nickel, which is usually very expensive. In addition, from a technical point of view, these grades cause some problems in some applications because of their relatively low tensile properties (especially yield strength) and resistance to stress corrosion under annealed conditions. It is also known that the Worthfield-fertilizer iron type stainless steel is mainly composed of a mixture of ferrite iron and Worthite iron, for example, according to Ep丨(10)88 standard steel 1.4362, 1.4655, 1.4477, 1.4462, 1.4507, 1.4410 1, 1.451 and 1.4424, all containing more than 3.5% nickel. These steels are particularly resistant to corrosion and stress corrosion #. It is also known that the ferrite iron type or fat grain - Ma Tian loose iron stainless steel grade 9 200815613 product 'for a clear heat treatment range, its microstructure consists of two components (fertilizer iron and 麻田散铁, in a 50/50 ratio Good, such as the 14017 grade according to the EN10088 standard). These grades (chromium content usually below 2〇0/〇) have high tensile mechanical properties, but corrosion resistance is not satisfactory. 'In addition' also wishes to simplify the method of manufacturing stainless steel sheets, strips, rods, sticks, wires or blocks. SUMMARY OF THE INVENTION The object of the present invention is to provide high mechanical properties (especially tensile strength higher than 4 〇〇 or even 45 0 MPa in an annealed or dissolved state) and high corrosion resistance ( In particular, it is the same as or better than 3〇4L), good microstructure stability in the 4-joint area and good edge resistance, and stainless steel without adding expensive additional elements and provides a method that is easier to implement. Steel rafts, strips, rods, sticks, wires or blocks to remedy the shortcomings of prior art steels and manufacturing methods. For this purpose, the first object of the invention is a double stainless steel, • its composition, in % by weight: C < 0.05% 21% < Cr < 25% 1% < Ni < 2.95% 0.16 % < N < 0.28% Μη < 2.0%

Mo + W/2 < 0.50%

Mo < 0.45% W < 0.15% 10 200815613

Si < 1.4% A1 < 0.05% 0.11% < Cu < 0.50% S < 0.010% P < 0.040%

Co < 0.5% rare earth metal (REM) < 0.1% V < 0.5% ® Ti < 0.1%

Nb < 0.3%

Mg < 0.1% The remainder is iron and impurities derived from smelting, and its microstructure is composed of Worthite iron and strontium to 65 vol% ferrite iron. The composition also satisfies the following relationship: 40幺IF 1 70 , 40 < IF 幺 60 is preferred where IF = 6x (% Cr + 1.32x% Mo + 1.27x% Si) - 10x (%Ni + 24x%C + • 16.15x%N + 0.5x%Cu + 0.4 X%Mn) - 6.17 and

Ilcr 1 30.5, preferably ILCR > 32

Ilcr = %Cr + 3·3χ%Μο + 16x%N + 2.6x〇/〇Ni - 0·7χ%Μη ° The steel according to the invention may also comprise the following individual or combined optional features: - Proportion of fat iron Between 3 5 and 5 5 vol%; 11 200815613 - chrome content between 22 and 24 ❶ / ;; a turbulent content of less than 1.5% by weight; - a calcium content of less than 0.03 wt% •, and a The molybdenum content is higher than 0.1% by weight. A second subject of the invention comprises a method of making a hot rolled sheet, strip or coil from a steel according to the invention, wherein: an ingot or slab of steel providing the composition of the invention; and ~ the ingot or thick The sheet is hot rolled at a temperature between 115 Å and 1280X: to obtain a plate, strip or coil. In a particular embodiment, the ingot or slab is hot rolled at a temperature between 丨丨 and 128 〇C to obtain a so-called four-open slab; thereafter, between 9 〇〇 and u〇 ( The temperature between rc is heat treated; and the plate is cooled by air quenching. A third subject of the invention includes a method of making a hot rolled rod or stick from steel according to the invention, wherein - is provided in accordance with the invention Continuous ingot or block of steel consisting of: ~ The ingot or block is produced at a temperature between 1150 and 1280 ° C to obtain a rod (which is air cooled) or stranded a coil (which is cooled by water); and thereafter, selectively: - heat treated at a temperature between 90 Torr and 1100 ° C; and a rod or strand is quenched and cooled. A special embodiment After cooling, a cold drawing operation is performed on the rod or a mold stretching operation is performed on the rod. 12 200815613 The invention also includes a method of manufacturing a steel block, wherein the cold forming operation: according to the invention And the obtained hot rolled rod is carried out; and also includes a system 2: forging The method in which the hot rolled rod obtained according to the present invention is cut into gold "and then on the metal block between 11 and 128"

Perform a forging operation. A variety of products of T can also be obtained by the method according to the invention and its use, such as

A hot-rolled steel four-size slab with a thickness between 5 and 100 mm: used with strips and coils, which can be used to make materials for manufacturing or energy-making equipment = component components, especially for between - (10) and bribes Operational components; between 50 and 3〇〇C, which are preferred for the material and energy manufacturing equipment; non-rolled steel crucibles, which can be obtained by cold rolling of hot rolled coils; 18 to 250 mm hot rolled rods and 4 to 96 mm diameter cold drawn rods, this product can be used to make mechanical parts (such as crying and shaft motors and engine shafts) and in corrosive media The operation of the joint and any 苟 4 亳 to 毫 w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w w Manufacture of woven or knitted metal fabrics for the filtration of chemicals, 'or for products; one piece; forgings, which can be used to make brackets or adapters; and, cattle, by making steel according to the invention 13 200815613 The following description, which is merely an example, will be read to understand the features and advantages of the present invention. Charge [Embodiment] The double stainless steel according to the present invention contains the content defined below. The carbon content of this grade is equal to or lower than 〇〇5 wt%, which is better than “3 Μ. This is because the content of this element is too high because it increases the precipitation of chromium carbide in the heat affected zone of the splicing. Reduce the local residualness by risk. The chromium content of this grade is between 21 and 25% by weight, preferably between U and 24% by weight to obtain good resistance, which is at least compatible with The type 304 or 304L grade is equivalent. The nickel content of this grade is between ! and 2 95%, preferably equal to or lower than D/0 A or even less than Μ% by weight. Add this to form Vostian 70% of iron to obtain a good crack resistance to the surname. When the content is greater than (10), more than U% by weight, it has a favorable effect on resisting the pitting of the Pitting. However, the content is limited. When it is higher than 2 95% by weight, the propagation of the Guanlan pit is reduced. The addition of the record also enables it to obtain the initial/ductive female association of the good son. This is because of its advantage that the dynamic transition curve is toward low temperature = change. 'This is when making thick four-open size plates (the nature of which is quite important) It is advantageous. Since the nickel content of the steel according to the invention is limited, it has been found that in order to obtain a suitable Worth iron content after the heat treatment between η and 900 (: and 11 〇〇. An unusual amount of other elements that form the iron and iron and limit the amount of iron that forms the ferrite. 14 200815613 The nitrogen content of this grade is between 〇16 and 〇28. It is often said that nitrogen is fed; B Rimen m 1 s γ 匕 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先 先Good stress tolerance), and also obtained metal with ancient mechanical strength. There are two 〃 庶 〃 庶 〃 〃 〃 〃 〃 〃 〃 〃 〃 〃 ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( When it is higher than 〇, the solubility problem will be observed; during the curing of slabs, blocks, surfaces or welds, bubbles will form. Manganese (which also forms Voss below 115 吖) Tian Tie's: Hold less than .% by weight, and below 1>5 % is better, this) because of the multi-faceted period of time. Therefore, 'this grade will cause problems in smelting and refining. This is because the refractory is used for attacking the ladle. Therefore, it must be replaced more frequently. These expensive elements, therefore, make the process more interrupted. Iron: Manganese addition (usually used to add this grade to the composition) also contains appreciable amounts of cans and crucibles that are not expected to be introduced into the steel. And in the fine, east, etc., and ασ 日守' difficult to remove these elements. The clock will also interfere with this refinement by limiting the decarburization effect. It is further downstream of the method = yes, title, its Because of the formation of vulcanization clocks (MnS) and oxidized inclusions, and the alignment of grades, this element is often added to the grade (10) where nitrogen is desired to increase the solubility of the element in the grade. This nitrogen content cannot be reached in steel when the bell content is insufficient. However, the inventors have found that it is possible to limit the addition in the steel according to the invention and simultaneously add a sufficient amount of nitrogen to achieve the desired effect on the ferrite-Worthian iron balance of the base material and 15 200815613 The heat affected zone of the stability weld.锢 (-the element that forms the fertilized iron) is maintained at a level lower than "%, and the crane is maintained at a level of less than 0.15 重量 旦 Du π Λ / Γ 1 坆 坆 坆 使 使 使 使 使The sum of W/2 is less than 0.50 ri. More preferably, it is less than 〇·4% by weight and less than 0.3% by weight. This is because the inventors have found that hunting by maintaining 9 elements and their contents and below the values shown, does not observe the precipitation of intercalated intermetallics 'by this' #由使敎敎Or the sheet or strip after the hot working is cooled by air, in particular, the method of manufacturing the steel sheet or strip can be alleviated. In addition, it has been observed that the solderability of these elements' grades is controlled by controlling the limits within the stated limits. Preferably, however, the minimum molybdenum content is maintained at 0.1% to improve the hot forgeability of this grade. In addition, grades with a smelting indium content of less than 0.1% will impose significant restrictions on the use of recycled waste for this grade, thus causing processing problems, particularly the use of a feed consisting of 100% pure iron alloy. The amount of copper (an element that forms the Vostian iron) is present. This element improves the corrosion resistance in an acid medium having a reducing power. However, its content is limited to 0.50% by weight to prevent formation! : Phase (hope to prevent this phase, which is because these lead to hardening of the ferrite grain iron phase and double alloy brittleness). The oxygen content is preferably limited to 0. 010% by weight to improve the forgeability. Boron is an optional element which may be between 0.0000% by weight and 〇〇1 by weight/〇 (preferably between 0.0005 wt% and 0.0000 wt%, between 0.0005 wt% and The amount between 0. 003% by weight and more preferably is added to the grade according to the invention of 16 200815613 to improve its thermal conversion. However, in another specific embodiment, it is preferred to limit the boron content to less than 0.0000 weight. To limit the risk of cracking during welding and continuous casting. Niobium (an element forming ferrite iron) is present in an amount of less than 14% by weight. Aluminum (an element forming ferrite iron) is present in an amount of less than 重量5 wt/〇, and preferably between 0.005 wt% and 0.040 wt%, to obtain a low-melting calcium aluminate inclusion. The maximum aluminum content is also limited to prevent excessive formation of vaporized aluminum. The role of these two elements (矽 and aluminum) is essentially to ensure deoxidation of the steel bath during smelting. Cobalt (an element forming the Vostian iron) is maintained at a level of less than 〇5 by weight/〇 to less than 0·? .... element. In particular, after the components of the device

A rare earth metal (represented by REM), preferably 0.06 wt%, is added to the composition. Limit the content of these two elements for this reason. At 0.2 hunger (an element that forms fertilized iron), Q • 2% by weight is preferred) added to this grade, I insect. • 5% by weight (in low amounts to improve the steel's resistance to cracking 5% by weight (to lower its content by virtue of the shape of nitriding, limited to 0.050 铌 (an element that forms ferrite) • 0 50% by weight is better.) It is helpful to improve the tensile strength of this grade to form coarse-grained tantalum nitride. 17 200815613 鈇 (an element that forms ferrite) The amount of 重量·i weight G/❶ (preferably less than 0_02% by weight) is added to this grade to limit the formation of titanium nitride (especially the formation of tantalum nitride in liquid steel). Calcium is added to the grade according to the invention such that the calcium content is less than 0.03 weight ❹ /., preferably more than 0 〇〇〇 2% by weight, more than 〇〇〇〇 5 weight % % More preferably, it controls the nature of the oxide inclusions and improves the machinability. The content of this element is limited because it is easy to form calcium sulfide with sulfur (which reduces corrosion resistance). In a preferred embodiment, The calcium content is limited to less than 0.0005% by weight, less than 〇〇〇〇2% by weight Preferably, the melon 3 is maintained at less than 〇〇1〇% by weight and is preferably less than 〇% by weight. As mentioned above, this element forms a sulfide with manganese or calcium, and the presence of the sulfide will impair the corrosion resistance. Sulfur is considered as an impurity. Magnesium may be added in an amount such that the final content is 〇1% to modify the nature of the sulfides and oxides. It is preferable to maintain the content of less than 0.005% by weight, which is preferable because it impairs corrosion resistance. The bismuth is usually introduced in the form of impurities in the ferrite and manganese ingots and maintained at a level below ϋ·_% by weight, and is considered as an impurity. The remainder of the composition consists of iron and impurities. In addition to the foregoing, these two:: may be bismuth, tin, arsenic, lead or antimony. Tin may be less than 0.100 weight. It may be less than _wt% two /= quantity 0 / i 7 里 / 3 存在 and It is preferably less than 0.020 〇·〇〇ι〇" °·002. 铋 can be less than 00002% by weight and is present at 18 200815613 and less than 0.00005% by weight. Zirconium can be 〇〇 2% In addition, the inventors have found that when the weight ratio of chromium, molybdenum, nitrogen, nickel and manganese is equal to the following When the type, the grade product having good local corrosion resistance, i.e., resistance to form a pit or crack resistance:

Ilcr = %Cr + 3.3x〇/〇Mo + 16χ〇/〇Ν + 2.6x%Ni - 0.7x%Mn> 30.5 〇 - In the annealed state, the microstructure of the steel according to the invention is from Worthfield • Iron and fertilized iron are formed, preferably, at 1 〇〇 (after TC treatment for 1 hour, the phase is present in a ratio of 35 to 65 vol% (35 to 55 vol% particularly) of the granules. The following formula was also found to be appropriately described in the fertilizer content of η(10).c: IF=6x(〇/〇Cr + 1.32x〇/〇Mo + 1.27x〇/〇Si) - 10x(〇/〇Ni + 24x%C + 16·15χ〇/〇Ν +〇.5x%CU + 〇·4χ%Μη) _ 6·17.

Therefore, in order to make ll〇 (the ratio of ferrite and iron of TC is between 乃 and Μ%, the ferrite iron index IF must be between 4〇 and 7〇. 〇 in the annealed state, microstructure It does not contain the damage and its mechanical properties. (IV) 'Specially' W phase and other intermediaries. In the cold-processed state, 'a part of the Worthite iron can be converted into a Ma Tian loose iron. The temperature of the application and the amount of cold deformation applied. Generally, the steel of the present invention can be smelted and can be made from a thick 4 or a hot rolled sheet (so-called four-open size plate), but can also be a hot rolled strip. ^, can also be cold-rolled strips made of hot-rolled strips. #二, m-type hot rolling. These products can be converted into rods or stretched blocks by forging or heat conversion or cold 19 200815613 or a line for drawing a mold. The steel according to the invention may also be treated by casting, followed by or without heat treatment. To obtain the best possible performance, preferably the method according to the invention is used, wherein first A steel ingot, slab or block having a composition according to the invention is provided. , slabs or blocks are usually made by smelting the raw materials in an electric furnace, and then performing A脱D or v〇D type vacuum melting with decarburization: and then continuously casting in a bottomless mold, The grade is cast into the form of ingot, thick U彡 or block. It can also be directly cast into a thin plate form, especially by continuous casting in a relatively rotating roll. After slabs or blocks, this can be selectively reheated to a temperature between 11 50 and 128 (Tc, but can also be applied directly in continuous casting while the crucible is still hot, directly on the slab Processing. In the case of 'Haoyue', the slabs or ingots are then hot rolled to obtain a four-open size plate between the 5 and 1 house meters. The reduction ratio is usually between 3 and 3%. After that, the plate is heat treated and reheated to a temperature between 90 〇u〇 (rc) so that the precipitate formed at this stage is returned. Into the solution and after cooling. Provide air quenching according to the method of the present invention. Cold, which is easier to implement than the conventional water cooling method used for this type of special grade, which cools more quickly. However, it can still be water cooled when needed. This slow air cooling is particularly beneficial to The composition of the present invention has 臬#molybdenum 3, which has no damage and its use properties of the metal phase analysis 20 200815613. This cooling is particularly possible (μ to 2.rc / sec range rate After hot rolling, 'if it is intended to be conveyed in this state, the four-size plate can be flattened, cut and pickled. It can also be rolled in a strip rolling machine to a thickness of between 3 and 100,000.

Between meters. I In the case of long products from ingots or blocks, it can be hot-pressed through a groove in a single hot rolling mill on a multi-strand rolling mill at a temperature between 115 〇 and 128 〇. Between the rollers to get the rod or coil of the strand 'or roll. The ratio of the area to be worn between the primary block and the final product is preferably greater than 3 to ensure the internal integrity of the rolled product. When the s is tied to the rod, it is cooled by a simple air spray after leaving the rolling mill. When a rolled bar having a diameter of more than 13 mm is produced, it can be cooled by quenching it in a water tank when it leaves the rolling mill. When a rod having a diameter of 13 mm or less is produced, it can be spread in the form of a resistance on the conveyor, after the E is transported through a dissolution treatment furnace (between 850 t and 11 Torr.) for 2 to 5 minutes. , cooled by water quenching. If it is desired to complete the recrystallization of the structure and to slightly reduce the tensile properties, the furnace heat treatment between 900C and 1100C can be selectively applied to the rod or coil (which has been subjected to overheating treatment). After the rod or rod coil is cooled, a variety of thermoforming or cold forming treatments can be performed depending on the end use of the product. After being cooled, the strip can be subjected to a cold drawing operation or a rod can be subjected to a mold drawing operation. 21 200815613

The hot rolled rod may also be cold formed, or each A or after the rod is cut into small pieces of metal and then forged. ▲ To explain the present invention, a heat-generating material is produced and these are described with particular reference to Figs. Example ^ by vacuum induction melting of pure iron alloy raw materials, and then by nitriding under nitrogen partial pressure to add iron alloys to lead the 丨 丨 虱 and when the external helium pressure is 0.8 _ bar when casting into a metal molding Get 25 kg of laboratory ingots. Of these hot objects, only the heat-receiving materials 14441 and i4604 are in accordance with the present invention. ^ According to the industrial heating of the present invention, 150 tons of reference material 8768 were obtained. This = grade is smelted by melting in an electric furnace and then vacuum refined to remove &' to achieve the desired carbon content. It was then continuously prayed into a slab (cross-sectional area 2 220 x l 700 mm) and then heated to 12 Torr. After the crucible, it was hot rolled into four-thickness plates having thicknesses of 7, 12 and 20 mm. Thereafter, the resulting plate is heat treated at about 1 Torr (the TC is subjected to heat treatment, so that many of the precipitates present at this stage are returned to the liquid. After the heat treatment, the plate is cooled with water, and then planarized, Cutting and pickling. The weight of various grades refined on a laboratory scale or industrial scale: the composition is shown in Table 1; refined in an electric furnace, then refined and cast by A〇D, into 4疋 or continuous performance~ The composition of various industrial products or semi-finished products is also shown in Table 1. 22 200815613 Table 1

Heated material number 14441 14604 8768 14382 14383 14439 14426 14422 14425 14424 14660 Product 25 kg 25 kg 150 metric tons 25 kg 25 kg 25 kg 25 kg 25 kg 25 kg 25 kg 25 kg A1 0.014 0.012 0.0042 0.010 0.05 0.014 <0.002 <0.002 0.024 C 0.016 0.028 0.020 0.020 0.020 0.017 0.021 0.022 0.019 0.020 0.024 Cr 23.07 22.80 22.83 23.03 23.01 23.05 26.67 26.56 26.68 26.61 22.79 Cu 0.301 0.300 0.15 0.304 0.297 0.299 0.279 0.280 0.280 0.208 0.284 Μη 1.282 1.284 1.25 1.288 1.277 1.309 1.24 0.706 0.723 0.705 4.780 Mo 0.249 0.249 0.35 0.251 0.250 0.251 1.322 1.337 1.327 1.328 0.296 N 0.212 0.239 0.21 0.110 0.110 0.290 0.119 0.117 0.300 0.237 0.199 Ni 2.539 1.692 2.50 4.249 1.552 1.485 4.532 1.419 1.541 2.549 2.470 0 0.0049 0.0038 0.0042 0.0031 0.0039 0.0052 0.0316 0.0284 0.0205 0.0221 0.0033 P 0.023 0.023 0.024 0.024 0.024 0.022 0.025 0.022 0.025 0.022 0.025 s 0.0009 0.0010 0.0005 0.0008 0.0008 0.0009 0.0209 0.0203 0.0210 0.0203 0.0014 Si 0.430 0.358 0.44 0.399 0.455 0.403 0.424 0.391 0.407 0.408 0.494 V 0.121 0.061 0.064 0.123 0.122 0.120 0.106 0.102 0.109 0.107 0.013 w < 0.010 < 0.010 0.019 < 0.010 < 0.010 < 0.010 < 0.010 < 0.010 < 0.010 < 0.010 < 0.010 Ti 0.0048 0.0017 0.007 0.0027 0.0039 0.0027 0.0041 0.0059 0.0047 0.0050 0.0011 Zr 0.0048 0.0052 0.0042 0.0049 0.0055 0.0064 0.0055 0.0060 0.0058 0.0072 0.0083 Co <0.002 <0.002 0.041 <0.002 <0.002 <0.002 <0.002 <0.002 < 0.002 <0.002 < 0.002 Ca < 0.0005 < 0.0005 0.0003 < 0.0005 < 0.0005 < 0.005 < 0.0005 < 0.005 < 0.0005 < 0.0005 < 0.0002 Nb < 0.002 < 0.002 0.0009 < 0.002 <0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 Se < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 <; 0.002 < 0.002 As < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 Ce + La < 0.0002 < 0.0002 < 0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 Mg <0.0005 <0.0005 0.0004 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 B <0.0005 <0.0005 0.0024 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 23 200815613 Table ι (continued)

Heater No. 304 304L 316L UNS32101 UNS32304 140301 436002 517077 533054 150091 Product * 氺氺氺氺* 氺氺* 氺A1 0.026 0.006 C 0.020 0.018 0.022 0.018 0.015 0.021 0.026 0.029 0.011 Cr 18.23 18.4 16.5 21.6 22.9 23.01 22.30 22.14 22.32 23.02 Cu 0.15 0.11 0.31 0.24 0.163 0.303 0.260 0.284 0.083 Μη 0.79 1.20 1.66 5.2 1.26 1.563 1.097 1.082 1.054 1.584 Mo 0.37 0.16 2.08 0.3 0.24 2.802 0.277 0.285 0.275 3.118 N 0.044 0.074 0.067 0.224 0.12 0.164 0.143 0.119 0.106 0.150 Ni 8.96 10.2 10.24 1.5 4.20 5.500 4.022 3.995 4.364 8.672 0 0.0037 P 0.023 0.020 0.019 0.027 0.028 0.022 0.022 0.023 0.019 s 0.0013 0.0011 0.0004 0.0008 0.0006 0.0004 0.0004 0.0006 0.0009 Si 0.37 0.50 0.71 0.40 0.206 0.414 0.464 0.400 0.390 V 0.103 0.114 0.058 0.126 w 0.028 0.017 0.013 0.022 Ti 0.0065 0.0040 0.0030 0.0033 Co 0.063 0.129 0.056 0.035 Zr . Ca 0.0007 0.0026 0.028 0.0007 Nb 0.0046 0.009 0.012 0.0063 Se < 0.0020 <0.0020 <0.0020 <0.0020 <0.0020 As Ce+La 0.0014 <0.0005 <0.0005 <0.0005 <0.0005 Mg 0.0008 <0.0005 <0.0005 0.0022 <0.0005 B * Rolled steel sheet or Steel bars or steel bars 24 200815613 The fat and iron of the granules of the fat granules will be taken from the laboratory heats (in the state of just casting) or from the industrial products (in the state of Pray) Samples of 1 to 8 cubic centimeters, which were heat treated at a number of different temperatures for 30 minutes in Yanluo, followed by water quenching after treatment to determine the ratio of ferrite to iron at elevated temperatures. Since the ferrite is magnetic (this is different from the Worth iron, possible carbides and nitrides), an analytical method for determining the saturation magnetization is used. The ferrite iron content thus measured is shown in Table 2 and plotted in Figure 1. There is a good correlation between θ 1 , , , , the number of members of the if and the iron content of the ferrite (measured by the base metal after it is treated). It has also been shown that the heat-receiving material 14441 is lower than η(8) according to the present invention. The ferrite iron content of C is suitable for thermal conversion into a dual structure. In addition, the ferrite iron content is suitable for stress corrosion resistance after heat treatment in a dry range of 95 ° C to 1 00 c. 25 200815613 Table 2 Heated materials 14382 14383 14441 14426 14422 14425 14424 140301 4360Q2 517077 533054 150091 Product ingots Ingots Ingots Ingots Ingots Ingots ingots CCB CCB CCB CCB CCB Immediately processed state 55.6 50.5 52.6 50.3 25.4 +900° C 45.6 89.5 54.4 71.2 98.7 100 91.9 45 51.0 47.2 20.5 +950〇C 48.7 87.1 51.7 71.1 98.8 99.6 94.6 42.8 48.9 46.1 25.4 +1000°C 50.9 90.0 54.5 71.8 99.4 99.4 93.4 50.8 42.1 50.7 46,0 28.8 +1050°C 55.7 81.0 53,0 77.8 98.6 99.1 78.8 54 44.2 54.6 48.3 33 7 +1100°C 60,8 84.6 55.5 82.0 99.0 87.4 75.4 58.6 47.6 59.4 51.3 36 1 +1150°C 65.2 88.6 59.0 88.1 98.9 75.6 78.1 64.6 52.7 66.7 57 9 41 1 +1200°C 76.6 94.2 64.0 95.4 98.8 78.4 71.6 59.3 75 5 64 R aa η +1250〇C 92.3 98.1 67.7 100 99.2 81.0 86.2 81.5 67.4 86 0 77 Ο Outside 0_ / 1 +1300°C 95.2 97.7 72.6 99.4 98.7 85.9 93.5 100 78.3 QQ 0 Q< Λ J 0 · A CC Λ 〇JU 00.4

CCB = continuous casting block 1.2 The final product of the ferrite grain iron containing barium is also determined by the grid method (according to ASTM E 562 standard) forged rods (which are heat treated at 10 ° C ° C) and tantalum beads (which are coated by The electrode has a stable energy derived from the ferrite iron content of the heat affected zone at 700 ° C deposited at a cooling rate of 2 (TC / sec cooling). The results (basic metal and ferrite iron content in the area affected by heat) are shown in Table 3. This shows that the enthalpy of the present invention 14441 and 14604 in the base metal and in the heat-affected zone contains a favorable local stress-resistance record, and is also advantageous (4) (refer to Table 26 200815613 HR: Hot rolled α BM: ferrite iron content measured on the base metal α ΗΑΖ : ferrite iron content measured in the heat affected zone 2. the castable cast key 14439 has bubbles and cannot be used. During the period of casting under the large (four) (4), it is confirmed that the nitrogen content of the heat-receiving material according to the present invention must be limited to less than 28% by weight. __·Heat transfer energy can be used for heat on the sample. The tensile test evaluates the thermal transition capability. The calibration portion of the sample (8 mm in diameter, 128 〇〇r. . Q long 5 hairs) is heated by the Joule and heated at 1280 C for 80 seconds. - Fertilizer iron content reference product a BM (%) a HAZ (%) 14441 * Forged rod - \ , __ 48 70 14604* Forged rod 54 65 14382 Forged rod _49 80 14383 Forged rod _79_ 88 14660 Forged φ__ 72 UNS S32101 HR board 45 67 UNS S32304 —--- HR board 47 75 test -"1- children, then cool to the test at 2C/sec capture rate = between _ and 128rc). At this temperature, the rapid tensile test was carried out at a rate of 73 mm/sec; after the rupture, 27 200815613, the neck diameter of the rupture was measured. The relative direct change (see Table 4) defined below reflects the thermal deformability: △ 0 = loo X (1-(final diameter / initial diameter)). Test _ Δ 0 (%) Temperature rc) Heated material 14382 Double hot material 14383 Heated material 14441* 1280 85.0 100.0 96.7 1250 98.3 86.7 1200 75.0 98.3 76.7 1150 70.0 95.0 61.7 1100 63.6 93.3 56.7 1050 51.7 75.0 44.2 1010 45.0 1000 65.0 40.0 980 960 58.3 36.7 950 35.8 900 35.0 S 1 7 ---- J 丄· / ^^__ * According to the invention. Tested by the thermal material 14 3 8 2 similar 4. Mechanical properties Table 4t Figure 2 (which represents the data in the form of a curve), it can be seen that the thermal deformability of the hot object 14441 is the same as ^ Ml On 14 ^8? Tea for Pingshu 28 200815613 Tensile properties 1〇.2 and Rm are determined according to the NFEN 10002-1 standard. Toughness Kv is determined at a number of temperatures according to the NF ΕΝ 10045 standard. Table 5 - Mechanical properties Reference product ^e0.2 (MPa) Rm (MPa) κν 20 ° C (Joules) κν -50〇C (Joules) 144411 Forged rods 477 716 334 51 146041 Forged rods 477 691 288 18 14382 Forged rod 436 664 > 339 339 14383 Forged rod 45 8 604 79 9 14660 Forged rod 493 701 293 31 304L HR plate 218 523 312 301 316L HR plate 232 537 307 298 UNS S32101 HR plate 466 720 101 60 UNS S32304 HR board 43 8 663 268 153 87681 HR board 519 743 29 1 HR according to the invention: hot rolled

Re0.2 : 0.2% strain yield strength Rm: tensile strength laboratory heat products 14441 and 14604 and industrial heat products 8768 (all three according to the invention) results show that the yield strength can be greater than 45OMPa, ie, twice The winner of the AISI 304L type Worthfield iron section steel. Laboratory heat products 14441 and 14604 and industrial heat products 8768 (this 200815613 are all according to the invention) at 2 (rc measured toughness values are greater than 2 〇〇 joules, taking into account the yield strength of some grades This is satisfactory afterwards. As for the heat product 14383 according to the text, the low nitrogen content and the high-fertilizer iron content are in the annealed state, and the toughness value at 20 ° C is less than 1 〇〇 joule. It was confirmed that a sufficient amount of nitrogen had to be added to obtain a satisfactory toughness.

Corrosion resistance tests were carried out on forged rods derived from laboratory heat and on sample embryos removed from hot rolled sheets derived from industrial heat. - Local resistance to aphid Resistance The pit corrosion resistance was evaluated by taking a potential curve and measuring the potential of the 丨=1 〇 〇 microamperes per square A knife. In a neutral medium with high chloride concentration ([〇] = 30 g/L) (pH = 6 4), at 5 (rc simulates the seawater in the sea Jc desalted 7 preparation) and at low This parameter was determined in a slightly acid medium (ρΗ = 5·5) with a chloride concentration ([C1·] = 250 ppm) at room temperature to simulate drinking water. The critical cavity temperature in the ferric chloride medium (6% FeCl3) is determined according to method c of the ASTM G48_(10) standard. In addition, in the series of tests, in the degassed neutral medium f containing 0.86 m / liter (corresponding to 5% by weight of NaC1), the refractory resistance was determined by hunger. A 900 second floating potential measurement was performed. Thereafter, the electromotive force curve is plotted at a floating potential of 100 volts at 4 inches/minute until reaching a concave, and the same potential is measured at a distance of 100 amps/cm 2 (five).

^ Under these conditions, the sample according to the present invention and the reference sample 304L and the like were tested. "1.4362 type Worthite iron - fat iron double grader. 30 200815613 Determination of critical cracks, black in neutral medium (ρίί = 6.4) in high chloride concentration = 3 and 4 J 30 g / liter) The sound & ancient H degree method to study the resistance to cracking and slick. It helps to arrange the floating (four) seam phase according to the recommendations listed in the ASTM G7 request standard. The critical crack temperature is the lowest observed crack depth of 25 microns. Temperature. The result of the heat of the table is ambiguous.

The values obtained are listed in 6. Comparing the plates made of S32304 and the rods obtained from 82 (the chemical composition of the two are similar), the results indicate that the corrosion resistance of the rod is lower than that of the hot-rolled sheet having the same composition. The inventors found the local resistance (four) number (ie, The formation of resistant cavities or cracks is abbreviated as Ilcr and is defined as: !lcr - Cr + 3.3xMo + 16xN + 2.6xNi - 0.7xMn (contents of Cr, Mo, N, Ni and Mn are expressed in % by weight The nickel content of all components classified by the local corrosion resistance is less than 6% (please refer to Figures 3, 4 and 5). The heat-receiving materials 14383 and 14660 (having an index of ILCR equal to 28.7 and 29.8) according to the present invention have less corrosion behavior than the steel of the AISI 304L type. The heat-receiving materials 14604 and 14441 (having an iLCR index of 30.9 and 3 3) according to the present invention behave at least as much as the 3〇4L steel. It has been found that to obtain a margin of at least equal to the AISI 304L grade, preferably, the steel according to the invention must have an ILCR greater than 30.5 and preferably greater than 32. Corrosion Resistance The characteristics of uniform corrosion were determined by evaluating the corrosion rate after soaking in a 2% dilute sulfuric acid solution heated to 40 ° C for 72 31 200815613 hours. Comparing the experimental heat containing 2.5% Ni and 0.2% bismuth (14441 according to the invention and 14660 not according to the invention) clearly shows the negative effect of the high Μ η content on the uniform corrosion resistance in the sulphuric acid medium. Table 6 - Local and Uniformity Principal Data Reference Product Ilcr Ει (V/ECS) e2 (V/ECS) e3 (V/ECS) Tcp (°C) Tcc (°C) V (mm/year) 14441* Forged sticks 33.0 0.165 1.058 0.320 7.5 50 0.73 14604* Forged rods 30.9 0.159 0.802 5 45 1.8 14382 Forged rods 35.8 0.302 1.323 0.420 15 60 0.24 14383 Forged rods 28.7 0.049 0.595 0.050 0 35 4.98 14660 Forged rods 29.8 0.094 0.707 7.5 45 1.11 304L HR plate ΝΑ 0.188 0.834 0.210 5 65 316L HR plate ΝΑ 0.266 0.865 7.5 75 UNS S32101 HR plate 26.4 0.163 0.855 12.5 UNS S32304 HR plate 35.7 0.413 1.3301 17.5 95 517077 Rolled rod 34.6 0.415 140301 Rolled Stick 47.1 1.2001 8768* HR board 33.1 0.227 1.2731

According to the oxidation potential of the solvent of the present invention, no cavity was observed 32 200815613

El: in a neutral medium (pH - 6.4) with a high chloride concentration ([Cl·] = 30 g/l), a cavity potential E2 at 5 °C: with a low chloride concentration ([cl1 = 25 〇 ppm) slightly acid environment _ = 5.5), the potential of the cavity at 25 E3: in the neutral chloride medium (5 〇 / 〇 NaCl), the potential of the cavity at 35t TCP: in the ferric chloride medium Critical cavity temperature

Tcc: critical crack temperature in a neutral medium (pH = 6.4) with a high chloride concentration ([C1-] = 3 gram / liter) V: uniform corrosion at 40 ° C in 2% sulfuric acid medium Rate 5.3 Re-purification of your steel sample was polished to 12 于 in water using SiC paper and then aged in air for 24 hours. The floating potential was measured for 15 minutes, and then the self-floating potential was dynamically polarized at a frequency of 1 mA amp/min to a potential of 3 〇〇 microamperes/cm 2 , and then returned to the potential of 电流, thereby proceeding at Cyclic polarization test in chloride media.

Thereby, the potential of the cavity (P-cavity) and the re-passivation potential of the previously formed cavity (V re-passivation) were measured. The results of the households are shown in Table 7. 〇 The relationship between the heat and the weight of the Ni- 匕 — 匕 毫 毫 毫 毫 382 382 382 382 382 382 14382 4.5 - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Potentiometric test, the higher the nickel content 33 200815613 :: The greater the difference between the potential and the repurification potential. This display is not conducive to the repassivation of the grade according to the invention of the month J concave/corrugated money. [Simple description of the diagram] Figure 1: Yu said. Diagram of the relationship between the % of ferrite iron after processing and the product IF processed in this way; Fig. 2 · The relationship between the relative diameter change Δ 0 and the deformation temperature; Fig. 3 · The cavity potentials E1 and E2 (in the forged rod (measured above) and the relationship of the index Ilcr;

Figure 4: Relationship between uniform corrosion rate v (measured on forged rods) and index; and Figure 5: plot of critical temperatures Tcc and Tcp (measured on forged rods) versus index 1 LCR. ^曰 [Main component symbol description]

34

Claims (1)

200815613 X. Patent application scope: L A double stainless steel consisting of C < 0.05〇/〇%·· 21% < Cr < 25% 1% < Ni < 2.95% 0.16% < N < 0.28% Mn < 2.0% Mo + ψ/2 < 0.50% < 0.45% w < 0.15% Si < 1.4% A1 < 0.05% 0.11% < Cu < 0.50% S < 0.010% p < 0.040% C〇 < 0.5% Rare Earth Metal (REM) 0.1% v < 0.5% Ti < 0.1% Nb < 0.3% Mg < 〇·ι% The remainder is composed of iron and impurities derived from smelting to 65 vol % ferrite, 4 〇 < IF &lt 70) and its microstructure consists of Vostian Tiehaihai and satisfies the following relationship: 35 200815613 where IF=6x (%Cr + 1.32x%Mo + 1.27x%Si) - 10x(%Ni + 24x%C + 16.15x%N + 0.5x%Cu + 0.4x%Mn) - 6.17 and LCR > 30.5 where Ilcr = %Cr + 3.3x%Mo + i6x〇/〇N + 2.6x〇/〇Ni - 0.7x〇/〇Mn 〇2· According to the steel of the scope of the patent application, characterized by: 32 Il of Ilcr 3 · Steel according to the patent application range of 1 or 2 irons between 35 and 55 vol%, characterized by fertilizer 4. According to the patent application scope 40 1IF < 60 〇 1 or 2 steel , which is characterized by: 5 • Between the 22nd and 24% by weight according to the i-th or the content of the patent application. 6. Steel according to the scope of the patent application or less than 1.5% by weight of 〇2, characterized by a steel of chromium 2, characterized in that manganese 7· is less than 〇·〇3 according to the scope of the patent application. %. 8. According to the scope of the patent application, it is included in 〇·1% by weight. Or 2 steels, characterized by a steel of 1 or 2 grades of calcium, characterized by a group of any of the 8 items of the 8th of the molybdenum, from the manufacture of hot rolled sheets and strips according to the scope of the patent application Or the method of the coil, which - provided according to the scope of the patent application! To 36 200815613 Ingots or slabs of Chengzhi Steel; and Γ or slabs at a temperature between 115 " σ _c ..., milk to pass to the plate, strip or coil. 10. The method according to claim 9, wherein: - the ingot or the slab is hot rolled at between 1150 and 1280t to obtain a so-called four-open size (quart0) plate; U0 (temperature between rc is heat treated; and The plate is cooled by air quenching. A U. A hot rolled steel four-way size plate available from the method according to claim 10 and having a thickness of between 5 and 1 mm. Ming, the use of hot-rolled coils obtained according to the method of 1 application for a special bean, 9 ..... for manufacturing structural components for material manufacturing or energy manufacturing devices. ο:·, 2 According to the application of the scope of patent application, the temperature operation of the material and the moonlight is between 〇〇 and 3〇〇. Between 〇, between 5〇 and 30 (rC is preferred. - 14~ a cold-rolled steel strip, which can be obtained by cold-rolling the hot-rolled coil obtained according to the ninth application of the patent application. A method of manufacturing a hot rolled rod or rod from a steel according to any one of the claims pp. 8 to 8, wherein: 'providing a continuous ingot or block of steel according to the patent application range 帛i to 8%; And the enthalpy of the ingot or block at a temperature between 115 〇 and 128 〇t: to obtain a rod (which is cooled by air) or a coil of wire (the Water 37 200815613 Cooling); and then, optionally, heat treatment at temperatures between 900 and 丨1〇〇. 忒 and coils of 忒 rods or strands are quenched and cooled. ...16_ - a hot rolled rod or hot rolled rod, which can be obtained from the method according to claim 15 of the patent, and the diameter of the hot dry rod is u. The diameter of the hot rolled rod is 4 mm to 3. mm. The method of claim 15 of the patent, wherein in the cooling, the cold stretching operation is performed on X Performing a mold stretching operation on the rod 18. A cold drawing rod or a mold stretching rod or wire, which can be obtained from the method according to claim 17 of the patent application, and the cold drawing rod has a diameter of 4 mm to 6 〇. Mm 'mold stretch rod or wire diameter from 0.010 mm to 20 mm. 】 9·- according to the application of the scope of the application of the rod, ;; for the manufacture of mechanical parts (such as pumps, valve shafts, motors and engines Axle) and an adapter that operates in a corrosive medium. 20. A type of rod or wire according to the scope of claim 1 or 18 which is used for the manufacture of cold formed sets, : extraction with ore, or manufacturing of woven or knitted metal fabrics for chemicals, minerals or foods. ^11. - A method for manufacturing steel blocks, in which the method of claiming 15 pieces of patent tracks The obtained hot-rolled bar is subjected to a cold forming operation. A steel piece can be obtained by the method according to the scope of the patent application. 38, 2008, 156, pp. 5; a method for manufacturing a steel forging, which will be based on f The hot-rolled bar obtained by the method of the patent of the eight-fun is cut into Metal block, then in the gold 24 to 1100. Forging operation between the war and the war. The method is obtained. The steel forgings can be borrowed according to the 23rd item of the patent scope: the system of profit, the forging of 4 items For the purpose, the 26·---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 39