Cold-rolled austenitic stainless steel and preparation method and application thereof
By adding carbon and nitrogen elements to stainless steel and optimizing the cold rolling process, the problem of strip-shaped defects in the stretching tank was solved, achieving high elongation and a high-end aesthetic effect, while reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TIANJIN TISCO & TPCO STAINLESS STEEL CO LTD
- Filing Date
- 2025-12-30
- Publication Date
- 2026-04-24
AI Technical Summary
Conventional 304 stainless steel is prone to stretching strip defects along the rolling direction during the processing of stretching water tanks. These defects affect the appearance and are difficult to remove, failing to meet the surface requirements of high-end bare stainless steel water tanks.
By increasing the carbon and nitrogen content in stainless steel and optimizing the cold rolling process, including multi-pass small-reduction rolling and cold rolling annealing, cold-rolled austenitic stainless steel is prepared, avoiding uneven deformation and martensitic phase transformation, and achieving high elongation and no strip defects.
This technology enables cold-rolled austenitic stainless steel to be used in the preparation of stretching water tanks without intermediate annealing, resulting in a surface free of strip-like defects. This meets the requirements for high-end bare-color water tanks, improves production efficiency, and saves costs.
Smart Images
Figure CN121915225A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of stainless steel technology, and in particular to a cold-rolled austenitic stainless steel, its preparation method, and its application. Background Technology
[0002] The stretched stainless steel sink is integrally molded without welds, making it less prone to dirt accumulation and with a smooth and beautiful surface. Compared with conventional ceramic and plastic materials, it is more corrosion-resistant and aesthetically pleasing. The main stainless steel grade used is 304.
[0003] However, when processing conventional 304 stainless steel into a stretch sink, not only is intermediate annealing required to solve the problem of stretch cracking, but obvious stretch strip defects along the rolling direction are also prone to appear at the bottom of the sink, which seriously affects the appearance of the sink and is difficult to remove in subsequent polishing, thus failing to meet the surface requirements of high-end bare stainless steel sinks.
[0004] Therefore, the search for a cold-rolled austenitic stainless steel free of stretching strip defects that can be used to prepare stretching water tanks has become a research hotspot. Summary of the Invention
[0005] To solve at least one of the above-mentioned technical problems, the present invention provides a cold-rolled austenitic stainless steel, its preparation method and application; and solves the problem of strip-shaped defects caused by uneven deformation along the rolling direction during the preparation of stretching water tanks.
[0006] In one aspect, the present invention provides a method for preparing cold-rolled austenitic stainless steel, comprising: hot-rolling, annealing, and pickling stainless steel material to obtain a No. 1 plate white raw material; reversibly cold-rolling the No. 1 plate white raw material to obtain a hardened steel plate; and cold-rolling, annealing, and pickling the hardened steel plate to obtain cold-rolled austenitic stainless steel; wherein the stainless steel material comprises carbon, silicon, manganese, phosphorus, sulfur, chromium, nickel, nitrogen, and iron.
[0007] Furthermore, the composition of stainless steel material, by mass fraction, includes: carbon: 0.055~0.08 wt%, for example, 0.057 wt%, 0.061 wt%, 0.068 wt%, 0.073 wt%, 0.079 wt%, etc.; silicon: less than 0.80 wt%, for example, 0.78 wt%, 0.69 wt%, 0.54 wt%, 0.42 wt%, 0.39 wt%, etc.; manganese: less than 2.00 wt%, for example, 1.7 wt%, 1.3 wt%, 1.1 wt%, 0.9 wt%, 0.7 wt%, etc.; phosphorus: less than 0.045 wt%, for example, 0.041 wt%, 0.039 wt%, 0.032 wt%, 0.029 wt%, 0.01 wt%, etc. 8 wt%, etc.; Sulfur: less than 0.003 wt%, for example, it can be 0.0028 wt%, 0.0021 wt%, 0.0019 wt%, 0.0016 wt%, 0.001 wt%, etc.; Chromium: 18.00~20.00 wt%, for example, it can be 18.3 wt%, 18.8 wt%, 19.1 wt%, 19.6 wt%, 19.8 wt%, etc.; Nickel: 8.00~10.00 wt%, for example, it can be 8.1 wt%, 8.6 wt%, 9.1 wt%, 9.6 wt%, 9.8 wt%, etc.; Nitrogen: 0.05~0.1 wt%, for example, it can be 0.063 wt%, 0.076 wt%, 0.086 wt%, 0.091 wt%, 0.098 wt%, etc.; Iron: balance.
[0008] Furthermore, in the stainless steel material, the total content of carbon and nitrogen elements, by mass fraction, is greater than 0.11%, for example, it can be 0.12wt%, 0.16wt%, 0.17wt%, 0.19wt%, 0.21wt%, etc.
[0009] Furthermore, the steps of reversibly cold rolling the No. 1 plate white raw material include: firstly, roughing rolling is performed using coarse rolls, and then finishing rolling is performed using fine rolls.
[0010] Furthermore, the roughness of the coarse roller is 2.0~3.0μm, for example, it can be 2.1μm, 2.3μm, 2.6μm, 2.7μm, 2.9μm, etc.
[0011] Furthermore, the roughness of the fine roller is less than 0.12 μm, for example, it can be 0.11 μm, 0.09 μm, 0.08 μm, 0.07 μm, 0.07 μm, etc.
[0012] Furthermore, the thickness of the hardened steel plate is 0.6~0.8mm, for example, it can be 0.63mm, 0.68mm, 0.71mm, 0.76mm, 0.79mm, etc.
[0013] Furthermore, in the step of cold rolling, annealing, and pickling the hardened steel plate, the annealing speed is 130~150 m / min, for example, it can be 136 m / min, 141 m / min, 143 m / min, 146 m / min, 149 m / min, etc.; and / or, the annealing temperature is 1140℃~1150℃, for example, it can be 1141℃, 1143℃, 1146℃, 1146℃, 1149℃, etc.
[0014] In another aspect, the present invention provides a cold-rolled austenitic stainless steel obtained by the above-described preparation method, wherein the elongation of the cold-rolled austenitic stainless steel is 65-72%.
[0015] In another aspect, the present invention provides an application of the above-mentioned cold-rolled austenitic stainless steel in the preparation of stretching tanks.
[0016] The technical solution provided by this invention has the following advantages: The present invention relates to cold-rolled austenitic stainless steel, its preparation method and application. By adopting the method of "increasing the content of C and N elements in stainless steel materials and optimizing the cold rolling process", the elongation of stainless steel materials is greatly improved, and the surface after stretching is free of strip-shaped defects along the rolling mill direction, which meets the requirements of high-end stretching water tank forming and surface.
[0017] Specifically, the role of adding C and N elements as interstitial atoms to stainless steel materials includes the following two aspects: (1) Enhanced stability of austenite: C and N, as interstitial atoms, are dissolved in the austenite lattice, suppressing martensitic phase transformation during deformation through lattice distortion and short-range ordered assembly. High interstitial atom content can increase stacking fault energy (SFE), prompting the deformation mechanism to shift from TRIP (transformation-induced plasticity) to TWIP (twin-induced plasticity) or dislocation slip, thus avoiding local brittleness caused by martensitic phase transformation.
[0018] (2) Defect suppression mechanism: Interstitial atoms eliminate strip-shaped defects along the rolling direction during water tank stretching by refining grains and homogenizing deformation. This is because C and N atoms hinder dislocation movement and promote dynamic recrystallization, reducing uneven deformation caused by local stress concentration.
[0019] Specifically, the optimization of the cold rolling process involves controlling the number of rolling passes and using multiple passes with small reductions (≤10% per pass) to avoid stress concentration and reduce the risk of strip defects.
[0020] Furthermore, in the process of preparing a drawn water tank using the cold-rolled austenitic stainless steel of this invention, a drawn water tank without drawn strip defects can be obtained through drawing without the need for an additional annealing process. This is because during the cold rolling process, the high content of interstitial C and N atoms in the cold-rolled austenitic stainless steel ensures the suppression of dislocation entanglement and promotes dislocation slip rather than the formation of a brittle phase. Attached Figure Description
[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.
[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.
[0023] Figure 1 A macroscopic structural diagram of a stretching water tank prepared using the cold-rolled austenitic stainless steel prepared in Example 1 of this invention; Figure 2 Comparative diagrams of the macroscopic structures of stretching water tanks prepared from cold-rolled austenitic stainless steels prepared in Comparative Examples 1 and 2 of this invention. Detailed Implementation
[0024] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.
[0025] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.
[0026] According to an embodiment of the present invention, a method for preparing cold-rolled austenitic stainless steel includes the following steps: S1: The stainless steel material (preferably, the black raw material of hot-rolled 304 steel with a thickness of 3.0mm, calculated by mass fraction, has a carbon content greater than 0.055%, a nitrogen content greater than 0.05%, and a carbon + nitrogen content greater than 0.11%) is hot-rolled, continuously annealed, and pickled to obtain the white raw material of plate No. 1; S2: The No. 1 plate white raw material obtained in step S1 is rolled by a 20-roll single-stand reversible cold rolling mill. The first pass uses rough rolls with a roughness of 2.0~3.0μm for roughing rolling, and the last pass uses fine rolls with a roughness of less than 0.12μm for finishing rolling, to obtain a hard steel plate with a thickness of 0.6~0.8mm, with no color difference on the surface and fine texture. S3: The 0.6~0.8mm hard steel plate obtained in step S2 is subjected to cold rolling annealing pickling treatment and online leveling to obtain 2B surface material with a grain size of 7.5~8, which is cold-rolled austenitic stainless steel. S4: Perform performance tests on the cold-rolled austenitic stainless steel obtained in step S3.
[0027] In some embodiments of the present invention, in step S1, the stainless steel material is 304 grade stainless steel, and the composition of the stainless steel material by mass fraction includes: carbon: 0.055~0.08%; silicon: less than 0.80%; manganese: less than 2.00%; phosphorus: less than 0.045%; sulfur: less than 0.003%; chromium: 18.00~20.00%; nickel: 8.00~10.00%; nitrogen: 0.05~0.1% and the balance iron.
[0028] In some embodiments of the present invention, in step S2, the function of "using coarse rolls for roughing rolling" is to improve surface roughness and color difference defects such as color difference in the No. 1 plate white raw material; the function of "using fine rolls for finishing rolling" is to reduce surface roughness and deformation by more than 70%.
[0029] The steel coils used in the following examples are all commercially available steel coils.
[0030] Example 1 This embodiment provides a cold-rolled austenitic stainless steel for tensile water tanks without tensile strip-shaped defects and its preparation method. S1: The stainless steel material is subjected to hot rolling, annealing and pickling treatment to obtain the No. 1 plate white raw material; the composition of the stainless steel material is shown in Table 1.
[0031] Table 1. Composition and specifications of the stainless steel material used in Example 1 S2: The No. 1 plate white raw material obtained in step S1 is rolled by roughing with a rough roll with a roughness of 2.1μm, and the last pass is rolled by fine rolling with a roughness of 0.1μm to obtain a hard steel plate of 0.8mm. S3: The hardened steel plate obtained in step S2 is subjected to cold rolling, annealing and pickling. The annealing speed is 130 m / min and the annealing temperature is 1140~1150℃. After online leveling, a 2B surface finished product is obtained, which is cold-rolled austenitic stainless steel. S4: Perform performance tests on the cold-rolled austenitic stainless steel obtained in step S3.
[0032] The performance test results are as follows: (1) The surface roughness of the cold-rolled austenitic stainless steel obtained in step S3 is 0.12μm, and the surface is fine with no color difference; (2) The elongation of the cold-rolled austenitic stainless steel obtained in step S3 is 68%; (3) The cold-rolled austenitic stainless steel obtained in step S3 is subjected to a stretching test in a water tank. No intermediate annealing step is required during the stretching process, and the prepared water tank exhibits no cracking or streaky color difference defects at the bottom. The prepared stretching water tank meets the usage requirements of high-end stretching bare-color water tank products. The macroscopic structure of the prepared stretching water tank is as follows: Figure 1 As shown.
[0033] Comparative Example 1 This comparative example provides a conventional cold-rolled austenitic stainless steel for stretching water tanks and its preparation method.
[0034] S1: The stainless steel material is subjected to hot rolling, annealing and pickling treatment to obtain the No. 1 plate white raw material; the composition of the stainless steel material is shown in Table 2; the thickness specification is 2.0mm.
[0035] Table 2. Composition and specifications of the stainless steel material used in Comparative Example 1 S2: The No. 1 plate white raw material obtained in step S1 is rolled through a roll with a roughness of 0.15μm to obtain a hardened steel plate of 0.8mm. S3: The hardened steel plate obtained in step S2 is subjected to cold rolling, annealing and pickling, wherein the annealing speed is 130 m / min and the annealing temperature is 1140~1150℃, and after online leveling, a 2B surface finished product is obtained, which is cold-rolled austenitic stainless steel. S4: Perform performance tests on the cold-rolled austenitic stainless steel obtained in step S3.
[0036] The performance test results are as follows: (1) The surface roughness of the cold-rolled austenitic stainless steel obtained in step S3 is 0.15 μm, and there is a slight color difference on the surface; (2) The elongation of the cold-rolled austenitic stainless steel obtained in step S3 is 58%; (3) The cold-rolled austenitic stainless steel obtained in step S3 was subjected to a tensile water tank test. The tensile water tank process requires an intermediate annealing step, and the prepared water tank exhibits cracking and obvious strip-shaped color difference defects at the bottom, which are difficult to remove with polishing, failing to meet the requirements for high-end stretched bare-color water tank products. Specifically, the cold-rolled austenitic stainless steel prepared in Comparative Example 1 and the cold-rolled austenitic stainless steel prepared in Example 1 were subjected to tensile water tank tests respectively. The macroscopic morphology comparison of the obtained water tanks is shown in the figure below. Figure 2 As shown in Comparative Example 1.
[0037] Comparative Example 2 This comparative example provides a conventional cold-rolled austenitic stainless steel for stretching water tanks and its preparation method.
[0038] S1: The stainless steel material is subjected to hot rolling, annealing and pickling treatment to obtain the No. 1 plate white raw material; the composition of the stainless steel material is shown in Table 3; the thickness specification is 2.0mm.
[0039] Table 3. Composition and specifications of the stainless steel material used in Comparative Example 2 S2: The No. 1 plate white raw material obtained in step S1 is rolled through a roll with a roughness of 0.15μm to obtain a hardened steel plate of 0.8mm. S3: The hardened steel plate obtained in step S2 is subjected to cold rolling, annealing and pickling, wherein the annealing speed is 130 m / min and the annealing temperature is 1140~1150℃, and after online leveling, a 2B surface finished product is obtained, which is cold-rolled austenitic stainless steel. S4: Perform performance tests on the cold-rolled austenitic stainless steel obtained in step S3.
[0040] The performance test results are as follows: (1) The surface roughness of the cold-rolled austenitic stainless steel obtained in step S3 is 0.15 μm, and there is a slight color difference on the surface; (2) The elongation of the cold-rolled austenitic stainless steel obtained in step S3 is 60%; (3) The cold-rolled austenitic stainless steel obtained in step S3 was subjected to a tensile water tank test. The tensile water tank process requires an intermediate annealing step, and the prepared water tank exhibits cracking. While the bottom of the water tank shows a noticeable reduction in strip-shaped color difference defects, these defects are still difficult to remove through polishing and cannot meet the requirements for high-end stretched bare-color water tank products. Specifically, the cold-rolled austenitic stainless steel prepared in Comparative Example 2 and the cold-rolled austenitic stainless steel prepared in Example 1 were subjected to tensile water tank tests, and the macroscopic morphology comparison of the obtained water tanks is shown in the figure below. Figure 2 As shown in Comparative Example 2.
[0041] Therefore, the cold-rolled austenitic stainless steel of this invention improves the stability of the stainless steel material during the stretching process by increasing the content of C and N elements in the stainless steel material and replacing the content of high-value elements such as Cu and Ni. When cold-rolled austenitic stainless steel is used to manufacture stretching tanks, it can meet the high elongation requirements of stretching tanks, and the intermediate annealing process is not required during the manufacturing process. It can also solve the problem of strip defects in high-end bare stainless steel tanks during stretching, greatly improving production efficiency and saving costs.
[0042] In summary, the cold-rolled austenitic stainless steel, its preparation method, and its application in this invention solve the problems of tensile cracking and strip-shaped defects at the bottom of the stretching tank after stretching. Compared with conventional methods, the process does not require increasing the content of high-value elements such as nickel and copper, thus solving the problems of tensile cracking and surface strip-shaped defects, saving costs, avoiding resource waste, and being more economical and reliable.
[0043] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0044] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for preparing cold-rolled austenitic stainless steel, characterized in that, include: Stainless steel material is subjected to hot rolling, annealing and pickling treatment to obtain No. 1 plate white raw material. The No. 1 plate white raw material is reversibly cold rolled to obtain a hardened steel plate; The hardened steel plate is subjected to cold rolling, annealing, and pickling treatment to obtain cold-rolled austenitic stainless steel. The stainless steel material is composed of carbon, silicon, manganese, phosphorus, sulfur, chromium, nickel, nitrogen, and iron.
2. The preparation method according to claim 1, characterized in that, The stainless steel material comprises, by mass fraction, the following components: Carbon element: 0.055~0.08wt%; Silicon content: below 0.80 wt%; Manganese content: below 2.00 wt%; Phosphorus: less than 0.045 wt%; Sulfur content: less than 0.003 wt%; Chromium: 18.00~20.00 wt% Nickel: 8.00~10.00 wt% Nitrogen: 0.05~0.1wt%; Iron: Balance.
3. The preparation method according to claim 2, characterized in that, Based on mass fraction, the total content of carbon and nitrogen in the composition of the stainless steel material is greater than 0.11%.
4. The preparation method according to any one of claims 1 to 3, characterized in that, The steps of reversibly cold rolling the No. 1 sheet white raw material include: First, roughing rolling is performed using coarse rolls, and then finishing rolling is performed using fine rolls.
5. The preparation method according to claim 4, characterized in that, The roughness of the coarse roller is 2.0~3.0μm.
6. The preparation method according to claim 4 or 5, characterized in that, The roughness of the fine roller is less than 0.12 μm.
7. The preparation method according to any one of claims 1 to 6, characterized in that, The thickness of the hardened steel plate is 0.6~0.8mm.
8. The preparation method according to any one of claims 1 to 7, characterized in that, In the step of cold rolling, annealing, and pickling the hardened steel plate The annealing rate is 130~150m / min; And / or, the annealing temperature is 1140℃~1150℃.
9. A cold-rolled austenitic stainless steel obtained by the preparation method according to any one of claims 1 to 8, characterized in that, The elongation of the cold-rolled austenitic stainless steel is 65-72%.
10. The use of the cold-rolled austenitic stainless steel of claim 9 in the manufacture of stretching tanks.