301TK stainless steel and application thereof

Abstract

The invention provides 301TK stainless steel and application thereof. The 301TK stainless steel comprises the following components in percentage by weight: 0.08%-0.11% of C; 0.5%-0.7% of Si; 1.7% to 1.9% of Mn; p is less than or equal to 0.035%; s < = 0.004%; cr: 17.2% to 17.8%; 6.5%-6.9% of Ni; 0.6% to 0.9% of Cu; 0.03%-0.06% of N, and the balance Fe and other inevitable impurity elements. MD30: 5 to 20 DEG C. The invention further provides a production method and application of the 301TK stainless steel. The 301TK stainless steel has high extensibility and high corrosion resistance, can generate high strength after stamping deformation, and meets the technical performance requirements of high-end water tanks.

Description

Technical Field

[0001] The invention relates to the technical field of 301 stainless steel manufacturing, and in particular to 301TK stainless steel and application thereof. Background Art

[0002] At present, high-end water sinks are mainly processed and produced by 304 stainless steel, which contains Ni≥8.0. The production of high-end water sinks is about 15 million units / year, consuming pure Ni: 1.2 tons / year, while Ni resources are in short supply and Ni prices are high for a long time. In order to reduce Ni consumption and production costs in the high-end water sink industry, 301 stainless steel is considered to replace 304 stainless steel. Compared with 304 stainless steel (Ni: 8.0~10.5), 301 stainless steel (Ni: 6.0~8.0) has a lower Ni content and both are 300 series austenitic steel grades. There is a feasibility of using 301 stainless steel to replace 304 stainless steel in high-end water sinks. At the same time, the strength of 301 stainless steel after deformation is greater than that of 304 stainless steel. This feature can reduce the thickness of the material. Generally, the El of 301 stainless steel is less than 55%, which is less ductile than the 304 stainless steel (El>55%) used for high-end sinks and cannot meet the requirements for stamping high-end sinks. In addition, the corrosion resistance of general 301 stainless steel (PREN<17.2) is less than the corrosion resistance of 304 stainless steel (PREN>18.0) used for high-end sinks, resulting in the ductility and corrosion resistance of general 301 unable to meet the technical performance requirements of high-end sinks for stainless steel. Summary of the invention

[0003] In order to solve the above problems, the present invention aims to provide a 301TK stainless steel and its application. The 301TK stainless steel has high elongation and high corrosion resistance, and will produce high strength after stamping deformation, meeting the technical performance requirements of high-end water tanks.

[0004] In order to achieve the above-mentioned object, the present invention provides a 301TK stainless steel, wherein the components of the 301TK stainless steel include, by weight percentage: C: 0.08%-0.11%; Si: 0.5%-0.7%; Mn: 1.7%-1.9%; P: ≤0.035%; S: ≤0.004%; Cr: 17.2%-17.8%; Ni: 6.5%-6.9%; Cu: 0.6%-0.9%; N: 0.03%-0.06%, and the balance is Fe and other inevitable impurity elements.

[0005] In the present invention, MD30 refers to the temperature at which 50% of processing-induced martensite is generated when the processing amount is 30%, and also represents the highest temperature at which austenite is transformed into martensite induced by cold deformation. The value of MD30 has a great influence on various properties after cold deformation, and can be used as a reference standard for designing stainless steel components. A low value of MD30 is not conducive to the improvement of strength during cold deformation. A too large value of MD30 produces too much martensite during cold deformation, which reduces the plasticity of the material and the fatigue resistance, affecting the ductility of stainless steel. The present invention finally determines a reasonable composition ratio and processing technology through multiple laboratory tests and comparisons, and controls MD30, so that the 301TK stainless steel produced has high elongation and high strength. The MD30 of the 301TK stainless steel of the present invention is ≤20°C, for example, 5 to 20°C, and can be specifically 5°C, 10°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0006] In the present invention, the calculation method of MD30 can be:

[0007] MD30 = 551-462×(C+N)-9.2×Si-8.1×Mn-13.7×Cr-29×(Ni+Cu)-18.5×Mo…Formula I;

[0008] The element symbol in Formula I represents the content of the element in weight percentage (i.e., the number substituted for each element is the number after removing % from the element content, such as the number substituted for C is 0.08-0.11), and the unit of MD30 is °C.

[0009] In the above-mentioned 301TK stainless steel, by increasing the Cu element content, it is beneficial to stabilize the austenite structure, and at the same time it is beneficial to improve the stamping property and ductility of the stainless steel. The weight content of Cu in the 301TK is generally controlled to be 0.6% to 0.9%, and can be specifically 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9% and other specific values, as well as a range with any two of the above specific values ​​as endpoints. Further, the weight content of Cu in the 301TK can be controlled to be 0.6% to 0.7%, and can be specifically 0.6%, 0.61%, 0.62%, 0.63%, 0.64%, 0.65%, 0.66%, 0.67%, 0.68%, 0.69%, 0.7% and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0010] In the above-mentioned 301TK stainless steel, the C element is an element that strongly forms and stabilizes austenite and expands the austenite zone in austenitic stainless steel. Carbon forms austenite 30 times more than nickel. Carbon is an interstitial element that hinders the flow of metal during the deformation process and is detrimental to the deformation of the stamping water tank. The present invention is beneficial to improving the stamping performance by reducing the C content. The weight content of C in the 301TK stainless steel is generally 0.8% to 0.11%, and can specifically be 0.8%, 0.9%, 1.0%, 1.1% and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0011] In the above 301TK stainless steel, N is one of the elements that contributes most to the stabilization of the austenite phase. By increasing the N content, it is beneficial to increase the strength of the stainless steel and improve the corrosion resistance. The weight content of N in the above 301TK stainless steel is generally 0.03% to 0.06%, and can be specifically 0.03%, 0.04%, 0.05%, 0.06%, and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0012] In the above-mentioned 301TK stainless steel, the Cr element is an element that ensures the corrosion resistance of stainless steel. The present invention can improve the corrosion resistance of stainless steel by increasing the Cr content. At the same time, Cr is also an element that forms ferrite. The presence of a certain proportion of ferrite in austenite is beneficial to cold deformation and corrosion resistance. The weight content of the Cr element in the 301TK stainless steel is generally 17.2% to 17.8%, and can specifically be 17.2%, 17.3%, 17.4%, 17.5%, 17.6%, 17.7%, 17.8% and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0013] In the above-mentioned 301TK stainless steel, Ni, Mn, and N are austenite phase stabilizing elements, and insufficient Ni content will reduce the corrosion resistance and processability of stainless steel. The present invention can improve the corrosion resistance and processability of stainless steel by increasing the Ni content. The weight content of the Ni element in the 301TK stainless steel is generally 6.5%-6.9%, and can specifically be 6.5%, 6.6%, 6.7%, 6.8%, 6.9% and other specific values, as well as a range with any two of the above specific values ​​as endpoints. In some specific embodiments, the weight content of the Ni element in the 301TK stainless steel can be 6.5%-6.8%.

[0014] The weight content of Mn element in the 301TK stainless steel is generally 1.7%-1.9%, and can be specifically 1.7%, 1.75%, 1.8%, 1.85%, 1.9% and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0015] The weight content of Si element in the 301TK stainless steel is generally 0.5%-0.7%, and can be specifically 0.5%, 0.55%, 0.6%, 0.65%, 0.7% and other specific values, as well as a range with any two of the above specific values ​​as endpoints.

[0016] According to a specific embodiment of the present invention, the composition of the 301TK stainless steel may specifically include, by weight percentage: C: 0.0897%; Si: 0.605%; Mn: 1.733%; P: 0.031%; S: 0.0015%; Cr: 17.6%; Ni: 6.5%; Cu: 0.68%; N: 0.05%, and the remainder is Fe and other inevitable impurity elements.

[0017] According to a specific embodiment of the present invention, the composition of the 301TK stainless steel includes, by weight percentage:

[0018] C: 0.0855%-0.0897%; Si: 0.569%-0.605%; Mn: 1.733%-1.755%; P: ≤0.031%;

[0019] S: ≤0.0030%; Cr: 17.4%-17.6%; Ni: 6.5%-6.6%; Cu: 0.66%-0.68%; N: 0.05%-0.06%, the remainder is Fe and other inevitable impurity elements.

[0020] In some specific embodiments, the composition of the 301TK stainless steel may include, by weight percentage: C: 0.0897%; Si: 0.605%; Mn: 1.733%; P: 0.031%; S: 0.0015%; Cr: 17.6%; Ni: 6.5%; Cu: 0.68%; N: 0.05%, with the remainder being Fe and other inevitable impurity elements.

[0021] In other specific embodiments, the composition of the 301TK stainless steel may include, by weight percentage: C: 0.0855%; Si: 0.588%; Mn: 1.748%; P: 0.030%; S: 0.0014%; Cr: 17.5%; Ni: 6.6%; Cu: 0.67%; N: 0.05%, and the balance is Fe and other inevitable impurity elements.

[0022] In other specific embodiments, the composition of the 301TK stainless steel may include, by weight percentage, C: 0.0881%; Si: 0.569%; Mn: 1.755%; P: 0.029%; S: 0.0030%; Cr: 17.4%; Ni: 6.5%; Cu: 0.66%; N: 0.06%, with the remainder being Fe and other inevitable impurity elements.

[0023] Compared with the existing common 301 stainless steel, the 301TK stainless steel provided by the present invention increases the element content of Cu, N, Ni, and Cr, and reduces the element content of C, so that a 301TK stainless steel product with high elongation and high corrosion resistance can be obtained. In some specific embodiments, the elongation El of the 301TK stainless steel is ≥55%, and the pitting resistance equivalent PREN is ≥18.0. Furthermore, the pitting resistance equivalent can reach ≥19.

[0024] In the present invention, the calculation formula of PREN is: PREN=Cr%+3.3×Mo%+16×N%…Formula II,

[0025] In Formula II, each element symbol represents the content of the element in weight percentage (ie, the number substituted for each element is the number after removing % from the element content, such as the number substituted for Cr% is 17.2-17.8).

[0026] The present invention also provides a production method for the above-mentioned 301TK stainless steel, which comprises the following steps: steel billet smelting, slab heating, slab rolling, solution treatment, pickling and leveling, cold rolling, solution treatment and pickling in sequence; wherein the reduction rate of the cold rolling is 50%-70%; the solution treatment and pickling are carried out in a cold annealing and pickling furnace, the furnace temperature of the cold annealing and pickling furnace is 1200-1220°C, and the L / S (annealing speed) is 80mpm-90mpm.

[0027] In the above production method, the process of smelting the steel billet may include: dissolving the raw materials, then performing decarburization treatment in a converter argon oxygen decarburization refining (AOD) furnace, further purifying the molten steel through a reduction stage, and adding high-quality raw materials to adjust the composition at the end of blowing; blowing argon (element symbol Ar) and stirring in a ladle treatment process refining furnace (LT) to float inclusions in the molten steel, adsorbing the floating inclusions, adding raw materials in the ladle treatment process, adjusting the composition (generally fine-tuning), obtaining molten steel with a suitable composition (i.e., the composition meets the chemical composition of the above-mentioned 301TK stainless steel), and then controlling the casting speed through a slab continuous casting project to obtain a slab.

[0028] In the above-mentioned process of smelting the steel billet, argon blowing and stirring are carried out in the ladle treatment process refining furnace (LT), and the floating inclusions are adsorbed, which is conducive to obtaining purer molten steel. In some specific embodiments, the floating inclusions can be adsorbed by a covering agent.

[0029] In the above production method, the conditions for heating the slab are: the temperature is 1245-1280°C, for example, 1245-1265°C or 1250-1280°C, and the continuous heating time is less than or equal to 200 minutes.

[0030] In the above production method, when the slab is withdrawn from the heating furnace, the temperature of the slab is generally controlled to be 1200°C.

[0031] In the above production method, the slab heating process may specifically include: heating the slab in a heating furnace at 1245-1280°C, controlling the continuous heating time to be within 200 minutes, and controlling the temperature of the slab at 1200°C when it is taken out of the heating furnace. Further, in the above slab heating process, the surface oxide scale can generally be removed before rough rolling (which can be done by dephosphorization equipment), and the plate is rolled for 7 passes. The thickness of the plate can be 26 mm.

[0032] In the above production method, the finishing rolling temperature of the slab is generally controlled to be 1000°C to 1050°C.

[0033] In the above production method, the slab is rolled for 7 times. The slab is rolled to obtain a black coil having a thickness of 3.0 to 4.0 mm.

[0034] In the above production method, the specific process of slab rolling may include: the finishing temperature of the furnace coil mill is controlled at 1000-1050°C, and 3.0-4.0 mm black coils are obtained after 7 rolling passes, and hot rolling is performed to coil the coils at a temperature of 700-650°C. The coiled black coils are placed on the site and air-cooled to room temperature.

[0035] In the above production method, the conditions of the solution treatment are: the thermal annealing temperature is 1130-1140° C., and specifically the throughput speed is 50-60 mpm (meters per minute).

[0036] In the above production method, the solution treatment process may specifically include: subjecting the black coil obtained by rolling the slab to a solution treatment at 1130-1140°C thermal annealing, which process can fully restore the grain structure, and the passing speed can be controlled to 50-60 mpm to obtain a steel plate.

[0037] In the above production method, the acid used for pickling and leveling can be HNO3 and HF. In some specific embodiments, the acid used for pickling and leveling can be a mixed acid of HNO3 with a concentration of 104g / L and HF with a concentration of 45g / L.

[0038] In the above production method, the specific process of pickling and leveling may include: pickling the steel plate with a mixed acid of HNO3 with a concentration of 104g / L and HF with a concentration of 45g / L to remove the oxide scale on the surface of the steel plate; then leveling the steel plate to obtain white scale. In some specific embodiments, a leveling mill (SPM for short) may be used for leveling, and the white scale obtained by pickling and leveling is generally a high-quality white scale that meets the cold rolling benchmark.

[0039] In the above production method, the cold rolling reduction rate is generally controlled to be 50%-70%, and can be 50%, 55%, 60%, 65%, 70%, 75%, 80% and other specific values, and a range with any two of the above specific values ​​as endpoints. By controlling the cold rolling reduction rate, it is beneficial for the annealed material to have a suitable grain size and be suitable for the manufacture of stamping high-end water tanks.

[0040] In the above production method, the cold rolling is generally performed for 7-9 passes, for example, 7 passes, 8 passes, or 9 passes.

[0041] In the above production method, the cold rolling process may specifically include: sending the white skin into a cold rolling mill for 7-9 rolling operations, and the rolling reduction rate is controlled to be 50%-70%.

[0042] In the above production method, the solutionizing and pickling are generally carried out in a cold annealing pickling furnace, and the furnace temperature of the cold annealing pickling furnace is generally controlled to be 1200-1220°C, and can be specifically 1200°C, 1205°C, 1210°C, 1215°C, 1220°C and other specific values, as well as a range with any two of the above specific values ​​as endpoints. The L / S of the solutionizing and pickling is 80mpm-90mpm, and can be specifically 80mpm, 81mpm, 82mpm, 83mpm, 84mpm, 85mpm, 86mpm, 87mpm, 88mpm, 89mpm, 90mpm and other specific values, as well as a range with any two of the above specific values ​​as endpoints. By carrying out solutionizing and pickling operations on a plate with a thickness of 0.6-1.5mm under the above conditions, the plate is fully dissolved, and a 2B cold-rolled material with a grain size of 7.5 to 8.5 is obtained.

[0043] In the above production method, the solution and pickling process can specifically include: subjecting the 0.6-1.5 mm plate to solution and pickling operations in a cold annealing and pickling furnace at a temperature of 1200-1220°C and an L / S of 80-90 mpm, so that it is fully dissolved and a 2B cold-rolled material with a grain size of 7.5-8.5 is obtained.

[0044] The grain size of stainless steel products has a great influence on the stamping sink. Small grains are not conducive to the stamping performance, and large grains have a rough surface after stamping. The present invention controls the cold rolling and annealing processes to ensure that the grain size of the produced 301TK stainless steel is appropriate, the size is suitable for the processing requirements of stamping high-end sinks, and the surface is beautiful. In some specific embodiments, the grain size of the 301TK stainless steel can be controlled by controlling the cold rolling reduction rate (50-65%) during the cold rolling process, and controlling the annealing process during the solution and pickling process; further, by implementing a pure steel smelting process, controlling inclusions also helps to control the grain size of the stainless steel.

[0045] According to a specific embodiment of the present invention, the production method of the above 301TK stainless steel may specifically include:

[0046] 1. Billet smelting:

[0047] The steel billet is melted by the electric furnace, and then decarburized by the converter argon oxygen decarburization (AOD) furnace, and further purified by the reduction stage. At the end of the blowing, high-quality raw materials are added to adjust the composition. In the ladle treatment process refining furnace (LT), argon (Ar) is blown and stirred to make the inclusions in the molten steel float up, and the floating inclusions are adsorbed by the covering agent to obtain a purer molten steel. Raw materials are added during the ladle treatment process to fine-tune the composition to obtain molten steel with the right composition, and then the casting speed is controlled through the slab continuous casting process to obtain a slab.

[0048] 2. Slab heating:

[0049] The slab in step 1 is heated in a heating furnace at 1245-1280°C for a continuous heating time of less than 200 minutes. When the slab is taken out of the heating furnace, the temperature of the slab is controlled at 1200°C. Before rough rolling, the surface oxide scale is removed by a dephosphorization device, and the slab is rolled for 7 passes to obtain the slab, and the thickness of the slab can be 26 mm.

[0050] 3. Rolling of slab:

[0051] The finishing rolling temperature of the Steckel mill is controlled at 1000-1150°C, and the slab in step 2 is rolled for 7 passes to obtain a black coil of 3.0-4.0 mm, and then hot rolled at a coiling temperature of 650°C. The coiled black coil is placed on the site for air cooling to room temperature;

[0052] 4. Solution treatment: The black coil cooled to room temperature in step 3 is subjected to solution treatment at 1130-1140°C by thermal annealing to fully recover the grain structure at a speed of 50-60 mpm to obtain a fully solution-treated black coil;

[0053] 5. Pickling and leveling: The fully solid-dissolved black coil in step 4 is pickled with a mixed acid of 104 g / L HNO3 and 45 g / L HF to remove the oxide scale on the surface of the steel plate, and then leveled by a leveling unit to finally obtain high-quality white coil that meets the cold rolling benchmark;

[0054] 6. Cold rolling: the pickled white coil in step 5 is transferred to a cold rolling mill, and after 7 to 9 rolling operations, the rolling reduction rate is 50% to 70%, a plate is obtained, and the thickness of the plate can be 0.6 to 1.5 mm;

[0055] 7. Solution and pickling: The 0.6-1.5 mm plate is subjected to solution and pickling operations at a cold annealing and pickling furnace temperature of 1200-1220°C and L / S80-90mpm to fully dissolve it and obtain a 2B cold-rolled material with a grain size of 7.5-8.5, which is 301TK stainless steel.

[0056] The 301TK stainless steel provided by the present invention is a high-elongation, high-corrosion-resistant 301TK stainless steel, which can be used as stainless steel for high-end water tanks.

[0057] The present invention also provides the use of the above 301TK stainless steel in the manufacture of stamped sinks, springs, shrapnel, connectors, and IT electronic accessories. The 301TK stainless steel of the present invention has high elongation (El≥55%), can produce high strength performance after stamping deformation, and has good corrosion resistance (PREN≥18.0), which can meet the technical requirements for materials for stamping high-end sinks. In some specific embodiments, the above 301TK stainless steel can also be used in the manufacture of springs, shrapnel, connectors, high-strength and high-elongation IT electronic accessories, etc. due to its high elongation.

[0058] The beneficial effects of the present invention include:

[0059] 1. The 301TK stainless steel provided by the present invention increases the N, Ni, Cr, and Cu contents and reduces the C content compared to the existing ordinary 301 stainless steel, thereby obtaining a new 301TK stainless steel product for high-end water tanks with high elongation (El≥55%) and high corrosion resistance (PREN≥18.0).

[0060] 2. The 301TK provided by the present invention significantly saves Ni content compared to the existing 304 stainless steel for water tanks. In some specific solutions, the Ni content can be saved by 18.8%.

[0061] 3. After the 301TK stamped water tank provided by the present invention is subjected to the same deformation, its strength is 30% higher than that of 304 stainless steel. By utilizing this property, the thickness of the water tank can be reduced by 30%, the amount of materials used can be reduced, the energy consumption of the production process can be reduced, and a higher environmental benefit can be achieved.

[0062] 4. The 301TK provided by the present invention has good elongation and high strength after deformation of 301 stainless steel, which can meet people's needs for high elongation under high strength and can be used for the manufacture of products such as springs, shrapnel, connectors, and IT electronic accessories. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 This is a comparison chart of the YS changes during the processing of 301TK stainless steel in Example 1 and 304 used in current high-end sinks. DETAILED DESCRIPTION

[0064] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0065] Example 1

[0066] This embodiment provides a 301TK stainless steel. In terms of weight percentage, the composition of the 301TK stainless steel includes: C: 0.0897%; Si: 0.605%; Mn: 1.733%; P: 0.031%; S: 0.0015%; Cr: 17.6%; Ni: 6.5%; Cu: 0.68%; N: 0.05%, and the balance is Fe and other inevitable impurity elements.

[0067] The MD30 of the 301TK stainless steel of this embodiment is 18° C. The stainless steel is numbered 301TK(1).

[0068] The production method of the above 301TK stainless steel comprises:

[0069] 1. Billet smelting:

[0070] The steel billet is melted by the electric furnace, and then decarburized by the converter argon oxygen decarburization refining (AOD) furnace, and further purified by the reduction stage. High-quality raw materials are added at the end of blowing to adjust the composition. In order to obtain purer molten steel, argon (element symbol Ar) is continued to be blown and stirred in the ladle treatment process refining furnace (LT) to make the inclusions in the molten steel float up, and the floating inclusions are adsorbed by the already added covering agent. Raw materials are added during the ladle treatment process to fine-tune the final composition to obtain molten steel with the correct composition (in line with the chemical composition of the above-mentioned 301TK stainless steel), and then the casting speed is controlled to 1.1 mpm through the slab continuous casting project to obtain a slab with a specification of 220 mm thick × 1260 mm wide.

[0071] 2. Slab heating:

[0072] The slab obtained in step 1 is heated at 1250°C in a heating furnace, and the continuous heating is controlled within 200 minutes. When the slab is taken out of the heating furnace, the temperature of the slab is controlled at 1200°C; before rough rolling, the surface oxide scale is removed by a dephosphorization device, and 26 mm thick plates are obtained by rolling 7 times;

[0073] 3. Rolling of slab:

[0074] The finishing rolling temperature of the Steckel mill is controlled at 1000-1020°C, and the slab in step 2 is rolled for 7 passes to obtain a 3.5 mm black coil, which is then hot rolled at a coiling temperature of 650°C. The coiled black coil is placed on the site and air-cooled to room temperature;

[0075] 4. Solution treatment:

[0076] The black skin coil obtained in step 3 is air-cooled to room temperature, and then subjected to a solution treatment at 1130-1140°C by thermal annealing to fully restore the grain structure at a speed of 50-60 mpm to obtain a fully solution black skin coil;

[0077] 5. Pickling and leveling:

[0078] The fully solid-dissolved black coil obtained in step 4 is pickled with a mixed acid of 104 g / L HNO3 and 45 g / L HF to remove the oxide scale on the surface of the steel plate, and is leveled by a leveling unit to finally obtain a high-quality white coil that meets the cold rolling benchmark;

[0079] 6. Cold rolling:

[0080] The pickled white coil obtained in step 5 is transferred to a cold rolling mill, and after 7-9 rolling operations, the rolling reduction rate is controlled to be 65.7%; and a plate with a thickness of 1.20 mm is obtained by rolling;

[0081] 7. Solution treatment and pickling:

[0082] The 1.20 mm plate obtained in step 6 is subjected to solution and pickling operations at a cold annealing and pickling furnace temperature of 1210° C. and an L / S of 85 mpm to fully dissolve the plate and finally obtain a 2B surface cold-rolled stainless steel product with a suitable grain size.

[0083] Example 2, Example 3

[0084] Example 2 and Example 3 provide a 301TK stainless steel respectively. The chemical composition of the stainless steel is shown in Table 1, and the production method of the stainless steel is the same as that of Example 1. The produced 301TK stainless steels are numbered 301TK(2) and 301TK(3).

[0085] Table 1 is a comparison of the composition of 301TK in Examples 1-3 of the present invention with ordinary 301 and 304 for current high-end sinks (% in Table 1 is weight percentage). Table 2 is a comparison of the mechanical properties of cold-rolled 301TK stainless steel in Example 1 with ordinary 301 and 304 for current high-end sinks.

[0086] The calculation formula of MD30 in Table 1 is:

[0087] MD30=551-462×(C+N)-9.2×Si-8.1×Mn-13.7×Cr-29×(Ni+Cu)-18.5×Mo;

[0088] The calculation formula of PREN is: PREN = Cr% + 3.3 × Mo% + 16 × N%;

[0089] In the above two formulas, the element symbol represents the content of the element in weight percentage.

[0090] In Table 2, TS is tensile strength, YS is yield strength, El is elongation at break, and HV is Vickers hardness.

[0091] Table 1

[0092]

[0093] Table 2

[0094]

[0095] Figure 1 This is a comparison chart of the YS (yield strength comparison) changes during the processing of the 301TK stainless steel of Example 1 and the existing 304 for high-end sinks.

[0096] It can be seen from Table 1 and Table 2 that the ductility of the 301TK stainless steel provided by the present invention is significantly improved compared with the ordinary 301 stainless steel, and is equivalent to the ductility of the 304 stainless steel used for sinks.

[0097] Further, through Figure 1 It can be seen that under the same deformation, the yield strength of 301TK stainless steel is higher than that of 304 stainless steel for sinks. The yield strength YS of 301TK stainless steel after deformation is 30% greater than that of 304 stainless steel. The impact resistance of 1.2mm sink wall of 301TK is equivalent to that of 1.5mm sink wall of 304.

[0098] After the sink is formed by stamping, the surface quality of the sink made of 301TK stainless steel is equivalent to that of the sink made of 304 stainless steel, which fully meets the terminal technical requirements.

[0099] The 301TK water tank and 304 water tank have been subjected to the neutral salt spray test (NSS) in accordance with the standard GBT+10125-2012, and the corrosion resistance time is both greater than 500 hours, meeting the requirements.

Claims

1. A 301TK stainless steel, wherein the composition of the 301TK stainless steel comprises, by weight percentage: C：0.08％～0.11％； Si: 0.5% to 0.7%; Mn: 1.7%~1.9%; P: ≤0.035%; S: ≤0.004%; Cr: 17.2%~17.8%; Ni: 6.5% ~ 6.9%; Cu: 0.6% ~ 0.9%; N: 0.03% to 0.06%, the balance being Fe and other inevitable impurity elements.

2. The 301TK stainless steel according to claim 1, wherein: The MD30 of the 301TK stainless steel is 5-20°C; MD30 = 551-462×(C+N)-9.2×Si-8.1×Mn-13.7×Cr-29×(Ni+Cu)-18.5×Mo…Formula I; The element symbol in Formula I represents the content of the element in weight percentage, and the unit of MD30 is °C.

3. The 301TK stainless steel according to claim 1, wherein: The weight content of Cu in the 301TK stainless steel is 0.6%-0.7%.

4. The 301TK stainless steel according to claim 1, wherein: In terms of weight percentage, the composition of the 301TK stainless steel includes: C: 0.0855%-0.0897%; Si: 0.569%-0.605%; Mn: 1.733%-1.755%; P: ≤0.031%; S: ≤0.0030%; Cr: 17.4%-17.6%; Ni: 6.5%-6.6%; Cu: 0.66%-0.68%; N: 0.05%-0.06%, the remainder is Fe and other inevitable impurity elements.

5. The 301TK stainless steel according to claim 1, wherein: In terms of weight percentage, the composition of the 301TK stainless steel includes: C: 0.0897%; Si: 0.605%; Mn: 1.733%; P: 0.031%; S: 0.0015%; Cr: 17.6%; Ni: 6.5%; Cu: 0.68%; N: 0.05%, the remainder is Fe and other inevitable impurity elements.

6. The 301TK stainless steel according to claim 1, wherein: In terms of weight percentage, the composition of the 301TK stainless steel includes: C: 0.0855%; Si: 0.588%; Mn: 1.748%; P: 0.030%; S: 0.0014%; Cr: 17.5%; Ni: 6.6%; Cu: 0.67%; N: 0.05%, the remainder is Fe and other inevitable impurity elements.

7. The 301TK stainless steel according to claim 1, wherein: In terms of weight percentage, the composition of the 301TK stainless steel includes: C: 0.0881%; Si: 0.569%; Mn: 1.755%; P: 0.029%; S: 0.0030%; Cr: 17.4%; Ni: 6.5%; Cu: 0.66%; N: 0.06%, the remainder is Fe and other inevitable impurity elements.

8. The 301TK stainless steel according to claim 1, wherein: The El of the 301TK stainless steel is ≥55%.

9. The 301TK stainless steel according to claim 1, wherein: The PREN of the 301TK stainless steel is ≥ 18.0; The calculation formula of PREN is: PREN = Cr% + 3.3 × Mo% + 16 × N% ... Formula II, In Formula II, each element symbol represents the content of the element in weight percentage.

10. Application of the 301TK stainless steel according to any one of claims 1 to 9 in the manufacture of stamping sinks, springs, shrapnel, connectors, and IT electronic accessories.

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