High-hardness wear-resistant stainless steel for gasket and preparation method thereof

Abstract

The invention discloses high-hardness wear-resistant stainless steel for a gasket and a preparation method of the high-hardness wear-resistant stainless steel, and relates to the technical field of steel types and preparation methods thereof. The high-hardness wear-resistant stainless steel comprises the following chemical components in percentage by mass: less than or equal to 0.08% of C, less than or equal to 1.20% of Si, 1.00%-2.50% of Mn, less than or equal to 0.035% of P, less than or equal to 0.010% of S, 13.50%-15.00% of Cr, 0.20%-0.30% of Mo, 1.50%-3.00% of Ni, 0.20%-0.50% of Ti, less than or equal to 0.05% of Nb, 0.020%-0.080% of V, less than or equal to 0.015% of N and the balance of iron and impurities. By adjusting the components of the ferritic stainless steel and the content of each component, the obtained stainless steel has high hardness and wear resistance. When the composite material is used for preparing the flat washer, the connection stability and safety can be ensured.

Description

Technical Field

[0001] The invention relates to the technical field of steel grades and preparation methods thereof, in particular to a high-hardness wear-resistant stainless steel for washers and a preparation method thereof. Background Art

[0002] Flat washers, also called flat gaskets, are usually thin pieces of various shapes used to reduce friction, prevent leakage, isolate, prevent loosening or disperse pressure. As an important part of fasteners, the material selection of flat washers is crucial to ensure the stability and safety of the connection. Stainless steel is an ideal choice for flat washers due to its excellent corrosion resistance and mechanical properties.

[0003] Stainless steel, as an alloy steel, is mainly composed of elements such as iron, chromium and nickel, and may contain other alloying elements to improve its performance. According to different organizational structures, stainless steel can be divided into austenitic stainless steel, ferritic stainless steel, martensitic stainless steel and duplex stainless steel. Each stainless steel material has different wear resistance, mechanical properties and processing properties, and the applicable working environment and requirements are naturally different. The key factors for selecting stainless steel flat washers include: 1) Corrosion resistance: Stainless steel flat washers must have good corrosion resistance to resist the erosion of chemicals, moisture and oxygen in the working environment; 2) Mechanical properties: Stainless steel flat washers need to withstand certain pressure and shear force to ensure the stability of the connection; 3) Processing performance: The manufacturing process of stainless steel flat washers requires cutting, stamping and forming processes, so the stainless steel material needs to be easy to process and form.

[0004] In the prior art, CN107002200A discloses a ferritic stainless steel, which includes the following components: C: 0.005-0.050%, Si: 0.01-1.00%, Mn: 0.01-1.0%, P≤0.040%, S≤0.010%, Cr: 15.5-18.0%, Ni: 0.01-1.0%, Al: 0.001-0.10% and N: 0.005-0.06% and the balance is Fe, and the ferritic stainless steel has good formability and wrinkle resistance. However, the wear resistance, corrosion resistance and hardness of the ferritic stainless steel are not good, so when it is used to manufacture flat washers, the stability and safety of the connection cannot be ensured.

[0005] Therefore, on the basis of the existing ferritic stainless steel, its components and component contents are adjusted to obtain a stainless steel material for manufacturing washers. It is particularly important to ensure that the stainless steel material for washers has good processing performance and corrosion resistance while also having good hardness and wear resistance. Summary of the invention

[0006] In view of the above-mentioned prior art, the purpose of the present invention is to provide a high-hardness wear-resistant stainless steel for washers and a preparation method thereof, wherein the high-hardness wear-resistant stainless steel has the following chemical composition by mass percentage: C≤0.08%, Si≤1.20%, Mn1.00%-2.50%, P≤0.035%, S≤0.010%, Cr 13.50%-15.00%, Mo 0.20%-0.30%, Ni1.50%-3.00%, Ti 0.20%-0.50%, Nb≤0.05%, V 0.020%-0.080%, N≤0.015%, and the remainder is iron and impurities. The preparation steps of the high-hardness wear-resistant stainless steel include: smelting and casting to obtain a continuous casting billet; heating the continuous casting billet, cooling and coiling after rolling to obtain a hot-rolled steel strip; annealing, descaling, pickling and cold rolling the hot-rolled steel strip to obtain the high-hardness wear-resistant stainless steel. The invention adjusts the components and contents of the ferrite stainless steel to obtain stainless steel with high hardness and wear resistance, and can ensure the stability and safety of connection when the stainless steel is used to prepare flat washers.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] In a first aspect of the present invention, a high-hardness and wear-resistant stainless steel is provided, wherein the high-hardness and wear-resistant stainless steel is composed of the following chemical components in percentage by mass:

[0009] C≤0.08%, Si≤1.20%, Mn 1.00%-2.50%, P≤0.035%, S≤0.010%, Cr13.50%-15.00%, Mo 0.20%-0.30%, Ni 1.50%-3.00%, Ti 0.20%-0.50%, Nb≤0.05%, V 0.020%-0.080%, N≤0.015%, the balance is iron and impurities.

[0010] Preferably, the high-hardness wear-resistant stainless steel has a hardness of 25-35 HRC, a yield strength of 680 MPa-850 MPa, a tensile strength of 750-950 MPa, and a uniform elongation of 8%-12%.

[0011] A second aspect of the present invention provides a method for preparing high-hardness wear-resistant stainless steel, comprising the following steps:

[0012] (1) According to the chemical composition of high-hardness wear-resistant stainless steel, the steel is smelted and cast to obtain a continuous casting billet;

[0013] (2) After heating the continuous casting billet, cooling and coiling after rolling to obtain a hot-rolled steel strip;

[0014] (3) After annealing, descaling, pickling and cold rolling, the hot-rolled steel strip obtains high-hardness and wear-resistant stainless steel.

[0015] Preferably, in step (1), the smelting is carried out by using the three-step method of GOR-VOD-LF.

[0016] Further preferably, during the LF process, the total oxygen content before the addition of the Ti alloy is controlled to be ≤0.001%, the N content is ≤0.006%, and after the Ti alloy element is added, the lower electrode temperature is prohibited from being raised, and the weak stirring time is controlled to be ≥10 min.

[0017] Preferably, in step (1), the casting temperature is 1580±20°C.

[0018] Preferably, in step (2), the cross-sectional specifications of the continuously cast billet are (1150-1540) mm×(160-220) mm.

[0019] Preferably, in step (2), the heating temperature is 1150°C-1190°C, and the heating time is 180min-240min.

[0020] Preferably, in step (2), the rolling process is: subjecting the heated continuous casting billet to 7 passes of rough rolling to obtain an intermediate billet, and then subjecting the intermediate billet to 3 passes of furnace coil rolling.

[0021] Further preferably, during the rough rolling process, the rolling opening temperature is 1050°C-1100°C.

[0022] Further preferably, the thickness of the intermediate blank is 23-28 mm.

[0023] Further preferably, during the Steckel rolling process, the starting rolling temperature is 980°C-1000°C and the finishing rolling temperature is 800°C-850°C.

[0024] Preferably, in step (2), the coiling temperature is 650°C-680°C.

[0025] Preferably, in step (2), the thickness of the hot-rolled steel strip is 3.0-6.0 mm.

[0026] Preferably, in step (3), during the annealing process, the residual oxygen in the continuous annealing furnace is controlled to be 2%-6%, the heating section 1, the temperature control zone 1, 2 is 880±20℃; the heating section 2, the temperature control zone 3, 4 is 890±20℃; the heating section 3, the temperature control zone 5, 6 is 900±20℃; the heating section 4, the temperature control zone 7, 8 is 910±20℃; the heating section 5, the temperature control zone 9, 10 is 890±20℃. The cooling water volume P4 temperature is controlled to be 820±20℃, the P5 temperature is controlled to be 600±20℃, the TV value is controlled to be 80-140mm·m / min, and the P6 steel strip furnace temperature is <80℃.

[0027] Preferably, in step (3), during the descaling process, the pressure reduction of the descaling machine is controlled to be 70-85 mm and the tension is controlled to be 300-350 kN.

[0028] Preferably, in step (3), the pickling includes sulfuric acid pickling, primary mixed acid pickling and secondary mixed acid pickling.

[0029] Further preferably, during the sulfuric acid pickling process, the acid solution used is a 300-350 g / L H2SO4 solution, and the iron ion concentration is ≤60 g / L; the acid solution temperature is 85-95°C, and the pickling time is 55-80 s.

[0030] Further preferably, in a mixed acid pickling process, the acid solution used is composed of 8-150g / L HF solution and 90-110g / L HNO3 solution, the iron ion concentration is ≤40g / L, the acid solution temperature is 50-65°C, and the pickling time is 55-90s.

[0031] Further preferably, in the secondary mixed acid pickling process, the acid solution used is composed of 14-20g / L HF solution and 90-110g / L HNO3 solution, the iron ion concentration is ≤40g / L, the acid solution temperature is 50-65°C, and the pickling time is 50-90s.

[0032] Preferably, in step (3), during the cold rolling process, the cumulative deformation of cold rolling is controlled to be between 35% and 55%.

[0033] The third aspect of the present invention provides the use of the above-mentioned high-hardness and wear-resistant stainless steel in the preparation of washers.

[0034] Beneficial effects of the present invention:

[0035] The high-hardness wear-resistant stainless steel prepared by the present invention has the following chemical components by mass percentage: C≤0.08%, Si≤1.20%, Mn: 1.00%-2.50%, P≤0.035%, S≤0.010%, Cr: 13.50%-15.00%, Mo: 0.20%-0.30%, Ni: 1.50%-3.00%, Ti: 0.20%-0.50%, Nb≤0.05%, V: 0.020%-0.080%, N≤0.015%, and the balance is iron and impurities. The preparation steps of the high-hardness wear-resistant stainless steel include: smelting and casting to obtain continuous casting billets; heating the continuous casting billets, cooling and coiling after rolling to obtain hot-rolled steel strips; annealing, descaling, pickling and cold rolling the hot-rolled steel strips to obtain high-hardness wear-resistant stainless steel.

[0036] The present invention adjusts the element components and the content of each element component of ferritic stainless steel to obtain stainless steel with high hardness and wear resistance. When it is used to prepare flat washers, the stability and safety of the connection can be guaranteed. Specifically, the present invention improves the toughness by adding Ni, Mo, and Ti to the chemical composition of stainless steel, improves the wear resistance by controlling the appropriate Si and Mn content, and accurately controls the hardness of the finished product by controlling the cold rolling deformation. DETAILED DESCRIPTION

[0037] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0038] In the prior art, each stainless steel material is different in terms of wear resistance, mechanical properties and processing properties, and the applicable working environment and requirements are naturally different. As an important component of fasteners, the material selection of flat washers is crucial to ensure the stability and safety of the connection. For example, austenitic stainless steel is currently the main stainless steel used to prepare flat washers. Austenitic stainless steel has good plasticity and excellent corrosion resistance, and is suitable for preparing flat washers in harsh environments (seawater desalination or chemical environments). However, its cost is too high and its strength is low. In actual application, it is deformed significantly as the nut is tightened, and it cannot be reused. It is even easy to over-tighten the nut when it is tightened, and the gasket function is lost. The strength of ferritic stainless steel is slightly higher, but its corrosion resistance is poor. Therefore, how to optimize and improve its elemental composition and element component content on the basis of existing ferritic stainless steel to ensure the hardness, corrosion resistance and wear resistance of ferritic stainless steel, so as to ensure the stability and safety of the connection when it is used as a flat washer.

[0039] Based on this, the present invention provides a high-hardness and wear-resistant stainless steel, which includes the following chemical components by mass percentage:

[0040] C≤0.08%, Si≤1.20%, Mn 1.00%-2.50%, P≤0.035%, S≤0.010%, Cr13.50%-15.00%, Mo 0.20%-0.30%, Ni 1.50%-3.00%, Ti 0.20%-0.50%, Nb≤0.05%, V 0.020%-0.080%, N≤0.015%, the balance is iron and impurities.

[0041] Among the above components:

[0042] Carbon and nitrogen can increase strength and hardness by solid solution strengthening, but it is very difficult to completely remove nitrogen during the steelmaking process. In order to obtain good performance, the present invention controls the C content in the high-hardness wear-resistant stainless steel to ≤0.08% and the N content to ≤0.015%.

[0043] Silicon and manganese can be used as deoxidizing elements to improve the purity of molten steel and the surface quality of cold-rolled plates, and Mn can improve wear resistance. Therefore, the present invention controls the Si content to ≤1.20% and the Mn content to 1.00%-2.50%.

[0044] Chromium and molybdenum are ferrite forming elements. From the perspective of organizational structure, as the Cr content increases, the α ’ Mo can improve the corrosion resistance of steel, and the high-hardness and wear-resistant stainless steel prepared by the present invention belongs to low-chromium ferritic stainless steel. Therefore, the present invention controls the Cr content to 13.50%-15.00% and the Mo content to 0.20%-0.30%.

[0045] Niobium, titanium and vanadium are strong carbonitride forming elements, which can prevent the formation of chromium carbonitride, thereby avoiding intergranular corrosion. Nb, Ti and V themselves can also be dissolved into the steel lattice to cause lattice distortion, thereby strengthening the matrix. The addition of Ti can expand the proportion of equiaxed crystals in the solidified structure. In order to obtain a low ductile-brittle transition temperature and intergranular corrosion resistance, the present invention controls the Ti content to 0.20%-0.50%, the Nb content ≤0.05%, and the V content to 0.020%-0.080%.

[0046] Phosphorus and sulfur, as harmful elements in stainless steel, can reduce the corrosion resistance, plasticity and toughness of steel, causing quality problems in continuous casting and hot rolling. Therefore, considering the actual production, the present invention controls the P content in high-hardness wear-resistant stainless steel to be ≤0.035%, and the S content to be ≤0.010%. Excessive total oxygen content will cause serious oxidation of the added titanium alloy, which is harmful to the purity of the molten steel and continuous casting. Therefore, the present invention controls the total oxygen content of the titanium alloy before adding to be ≤0.001%.

[0047] Nickel is an austenite forming element, and the addition of nickel in stainless steel will not change the matrix structure, but can reduce the brittle transition temperature of the steel and improve its toughness. Therefore, the present invention controls the Ni content in the stainless steel to be 1.50%-3.00%.

[0048] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0049] The experimental materials used in the embodiments of the present invention are all conventional experimental materials in the art and can be purchased through commercial channels.

[0050] Example 1: High hardness and wear-resistant stainless steel

[0051] 1. Chemical composition (mass percentage)

[0052] C 0.04%, Si 0.06%, Mn 1.75%, P 0.15%, S 0.005%, Cr 14.50%, Mo 0.25%, Ni2.25%, Ti 0.35%, Nb 0.35%, V0.050%, N 0.0075%, and the balance is iron and impurities.

[0053] 2. Preparation method

[0054] (1) According to the chemical composition of high-hardness wear-resistant stainless steel, the steel is smelted and cast at 1580°C to obtain a continuous casting billet;

[0055] Among them, the three-step method of GOR-VOD-LF is adopted for smelting. During the LF process, the total oxygen content is controlled to be ≤0.001% and the N content is ≤0.006% before the Ti alloy is added. After the Ti alloy element is added, the lower electrode temperature is prohibited to be raised, and the weak stirring time is controlled to be ≥10min.

[0056] (2) a continuous casting billet with a cross-sectional specification of 1350 mm × 190 mm was heated at 1170° C. for 200 min; the continuous casting billet was subjected to 7 passes of rough rolling to obtain an intermediate billet with a thickness of 25 mm; the intermediate billet was further subjected to 3 passes of furnace coil rolling, cooled, and coiled at 665° C. to obtain a hot-rolled steel strip with a thickness of 4.5 mm;

[0057] Among them, during the rough rolling process, the opening temperature is 1075℃, during the furnace coil rolling process, the opening temperature is 990℃ and the final rolling temperature is 825℃;

[0058] (3) placing the hot-rolled steel strip in a continuous annealing furnace for annealing treatment, placing it in a dephosphorizing machine for descaling treatment, then performing sulfuric acid pickling, primary mixed acid pickling and secondary mixed acid pickling, and finally cold rolling to obtain high-hardness and wear-resistant stainless steel;

[0059] Among them, the residual oxygen of the continuous annealing furnace is controlled at 4%, heating section 1, temperature control zones 1 and 2 are 880±20℃; heating section 2, temperature control zones 3 and 4 are 890±20℃; heating section 3, temperature control zones 5 and 6 are 900±20℃; heating section 4, temperature control zones 7 and 8 are 910±20℃; heating section 5, temperature control zones 9 and 10 are 890±20℃. The cooling water volume P4 temperature is controlled to be 820℃±20℃, the P5 temperature is controlled to be 600±20℃, the TV value is controlled to be 110mm·m / min, and the P6 steel strip furnace temperature is controlled to be less than 80℃; the reduction of the phosphorus breaking machine is controlled to be 80mm, and the tension is controlled to be 325kN; during the sulfuric acid pickling process, the acid solution used is 325g / L H2SO4 solution, and the iron ion concentration is ≤60g / L; the acid solution temperature is 90℃, and the pickling time is 70s; during the primary mixed acid pickling process, the acid solution used is composed of 80g / L HF solution and 100g / L HNO3 solution, the iron ion concentration is ≤40g / L, the acid solution temperature is 60℃, and the pickling time is 75s; during the secondary mixed acid pickling process, the acid solution used is composed of 17g / L HF solution and 100g / L HNO3 solution, the iron ion concentration is ≤40g / L, the acid solution temperature is 60℃, and the pickling time is 70s.

[0060] Example 2: High hardness and wear-resistant stainless steel

[0061] 1. Chemical composition (mass percentage)

[0062] C 0.01%, Si 0.01%, Mn 1.00%, P 0.01%, S 0.01%, Cr 13.50%, Mo 0.20%, Ni 1.50%, Ti 0.20%, Nb 0.01%, V 0.020%, N 0.01%, and the balance is iron and impurities.

[0063] 2. Preparation method

[0064] (1) According to the chemical composition of high-hardness wear-resistant stainless steel, the steel is smelted and cast at 1560°C to obtain a continuous casting billet;

[0065] Among them, the three-step method of GOR-VOD-LF is adopted for smelting. During the LF process, the total oxygen content is controlled to be ≤0.001% and the N content is ≤0.006% before the Ti alloy is added. After the Ti alloy element is added, the lower electrode temperature is prohibited to be raised, and the weak stirring time is controlled to be ≥10min.

[0066] (2) a continuous casting billet with a cross-sectional specification of 1150 mm × 160 mm is heated at 1150° C. for 180 min; the continuous casting billet is subjected to 7 passes of rough rolling to obtain an intermediate billet with a thickness of 23 mm; the intermediate billet is further subjected to 3 passes of furnace coil rolling, cooled, and coiled at 650° C. to obtain a hot-rolled steel strip with a thickness of 3.0 mm;

[0067] Among them, during the rough rolling process, the rolling temperature is 1050℃, during the furnace coil rolling process, the rolling temperature is 980℃ and the final rolling temperature is 800℃;

[0068] (3) placing the hot-rolled steel strip in a continuous annealing furnace for annealing treatment, placing it in a dephosphorizing machine for descaling treatment, then performing sulfuric acid pickling, primary mixed acid pickling and secondary mixed acid pickling, and finally cold rolling to obtain high-hardness and wear-resistant stainless steel;

[0069] Among them, the residual oxygen of the continuous annealing furnace is controlled at 2%, heating section 1, temperature control zones 1 and 2 are 880±20℃; heating section 2, temperature control zones 3 and 4 are 890±20℃; heating section 3, temperature control zones 5 and 6 are 900±20℃; heating section 4, temperature control zones 7 and 8 are 910±20℃; heating section 5, temperature control zones 9 and 10 are 890±20℃. Control the cooling water volume P4 temperature to 820℃±20℃, P5 temperature to 600±20℃, control TV value to 80mm·m / min, P6 steel strip furnace temperature <80℃; control the reduction of the phosphorus breaking machine to 70mm, and the tension to 300kN; in the sulfuric acid pickling process, the acid used is 300g / L H2SO4 solution, and the iron ion concentration is ≤60g / L; the acid temperature is 85℃, and the pickling time is 55s; in the first mixed acid pickling process, the acid used is composed of 8g / LHF solution and 90g / L HNO3 solution, the iron ion concentration is ≤40g / L, the acid temperature is 50℃, and the pickling time is 55s; in the second mixed acid pickling process, the acid used is composed of 14g / L HF solution and 90g / L HNO3 solution, the iron ion concentration is ≤40g / L, the acid temperature is 50℃, and the pickling time is 50s.

[0070] Example 3: High hardness and wear-resistant stainless steel

[0071] 1. Chemical composition (mass percentage)

[0072] C 0.08%, Si 1.20%, Mn 2.50%, P 0.035%, S 0.010%, Cr 15.00%, Mo 0.30%, Ni 3.00%, Ti 0.50%, Nb 0.05%, V 0.080%, N 0.015%, and the balance is iron and impurities.

[0073] 2. Preparation method

[0074] (1) According to the chemical composition of high-hardness wear-resistant stainless steel, the steel is smelted and cast at 1600°C to obtain a continuous casting billet;

[0075] Among them, the three-step method of GOR-VOD-LF is adopted for smelting. During the LF process, the total oxygen content is controlled to be ≤0.001% and the N content is ≤0.006% before the Ti alloy is added. After the Ti alloy element is added, the lower electrode temperature is prohibited to be raised, and the weak stirring time is controlled to be ≥10min.

[0076] (2) heating a continuous casting billet with a cross-sectional specification of 1540 mm×220 mm at 1190° C. for 240 min; performing rough rolling on the continuous casting billet for 7 passes to obtain an intermediate billet with a thickness of 28 mm; performing furnace coil rolling on the intermediate billet for 3 passes, cooling the intermediate billet, and coiling the intermediate billet at 680° C. to obtain a hot-rolled steel strip with a thickness of 6.0 mm;

[0077] Among them, during the rough rolling process, the starting temperature is 1100℃, during the furnace coil rolling process, the starting temperature is 1000℃ and the final rolling temperature is 850℃;

[0078] (3) placing the hot-rolled steel strip in a continuous annealing furnace for annealing treatment, placing it in a dephosphorizing machine for descaling treatment, then performing sulfuric acid pickling, primary mixed acid pickling and secondary mixed acid pickling, and finally cold rolling to obtain high-hardness and wear-resistant stainless steel;

[0079] Among them, the residual oxygen of the continuous annealing furnace is controlled at 6%, heating section 1, temperature control zones 1 and 2 are 880±20℃; heating section 2, temperature control zones 3 and 4 are 890±20℃; heating section 3, temperature control zones 5 and 6 are 900±20℃; heating section 4, temperature control zones 7 and 8 are 910±20℃; heating section 5, temperature control zones 9 and 10 are 890±20℃. The cooling water volume P4 temperature is controlled to be 820℃±20℃, the P5 temperature is controlled to be 600±20℃, the TV value is controlled to be 140mm·m / min, and the P6 steel strip furnace temperature is controlled to be less than 80℃; the reduction of the phosphorus breaking machine is controlled to be 85mm, and the tension is controlled to be 350kN; in the sulfuric acid pickling process, the acid solution used is 350g / L H2SO4 solution, and the iron ion concentration is ≤60g / L; the acid solution temperature is 95℃, and the pickling time is 80s; in the primary mixed acid pickling process, the acid solution used is composed of 150g / L HF solution and 110g / L HNO3 solution, the iron ion concentration is ≤40g / L, the acid solution temperature is 50-65℃, and the pickling time is 90s; in the secondary mixed acid pickling process, the acid solution used is composed of 20g / L HF solution and 110g / L HNO3 solution, the iron ion concentration is ≤40g / L, the acid solution temperature is 65℃, and the pickling time is 90s.

[0080] Comparative Example 1:

[0081] The difference between this comparative example and Example 1 is that the stainless steel does not contain Mo, Ti, Nb and V.

[0082] Comparative Example 2:

[0083] The difference between this comparative example and Example 1 is that the stainless steel does not contain Mo, Ti and Nb.

[0084] Comparative Example 3:

[0085] The difference between this comparative example and Example 1 is that the stainless steel does not contain Mo, Ti and V.

[0086] Comparative Example 4:

[0087] The difference between this comparative example and Example 1 is that the stainless steel does not contain Mo, Nb and V.

[0088] Comparative Example 5:

[0089] The difference between this comparative example and Example 1 is that the stainless steel does not contain Ti, Nb and V.

[0090] Test Example 1:

[0091] According to GB / T 228.1-2021 "Metallic Material Tensile Test Part 1: Room Temperature Test Method", the tensile strength, yield strength and uniform elongation of the stainless steel obtained in Example 1 and Comparative Examples 1-5 were measured; according to GB / T 230.1-2018 "Metallic Material Rockwell Hardness Test Part 1: Test Method", the hardness of the stainless steel obtained in Example 1 and Comparative Examples 1-5 was tested; GB / T 17899-2023 "Metal and Alloy Corrosion Potentiodynamic Measurement Method for Pitting Potential of Stainless Steel in Sodium Chloride Solution" was used to test the corrosion resistance of the stainless steel obtained in Example 1 and Comparative Examples 1-5; the wear resistance of the stainless steel obtained in Example 1 and Comparative Examples 1-5 was tested by ball milling friction and wear test, wherein the test parameters were: load 600g, grinding material was GCr15, its diameter was 5mm, rotation speed was 500r / min, grinding time was 30min, and wear weight loss was tested. The results are shown in Table 1.

[0092] Table 1 Performance parameters of each group of stainless steel

[0093]

[0094] As can be seen from Table 1, the hardness of the stainless steel prepared by the present invention is 35HRC, the yield strength is 650MPa, the tensile strength is 950MPa, the uniform elongation is 12%, the corrosion potential is -0.18V, and the wear loss is 9.2mg. The stainless steel prepared in Comparative Example 1 does not contain the four elements of Mo, Ti, Nb and V, and its hardness is 25HRC, the corrosion potential is -0.82V, and the wear loss is 22.3mg. Compared with comparative example 1, only V element was added in comparative example 2, and the hardness of the stainless steel obtained was increased by 3HRC, the corrosion potential was increased by 0.07V, and the wear loss was reduced by 2.2mg; only Nb element was added in comparative example 3, and the hardness of the stainless steel obtained was increased by 2HRC, the corrosion potential was increased by 0.13V, and the wear loss was reduced by 2.8mg; only Ti element was added in comparative example 4, and the hardness of the stainless steel obtained was increased by 2HRC, the corrosion potential was increased by 0.10V, and the wear loss was reduced by 2.5mg; only Mo element was added in comparative example 5, and the hardness of the stainless steel obtained was increased by 1HRC, the corrosion potential was increased by 0.21V, and the wear loss was reduced by 3.4g. It can be seen that the present invention has a synergistic effect in improving the hardness, wear resistance and corrosion resistance of stainless steel by adding four elements of Mo, Ti, Nb and V to the elemental composition of existing ferritic stainless steel.

[0095] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high-hardness and wear-resistant stainless steel, characterized in that: It is composed of the following chemical components in mass percentage: C≤0.08%, Si≤1.20%, Mn 1.00%-2.50%, P≤0.035%, S≤0.010%, Cr 13.50%-15.00%, Mo0.20%-0.30%, Ni 1.50%-3.00%, Ti 0.20%-0.50%, Nb≤0.05%, V 0.020%-0.080%, N≤0.015%, the balance is iron and impurities.

2. The method for preparing the high-hardness wear-resistant stainless steel according to claim 1, characterized in that: The following steps are involved: (1) According to the chemical composition of high-hardness wear-resistant stainless steel, the steel is smelted and cast to obtain continuous casting billets; (2) After heating the continuous casting billet, cooling and coiling after rolling to obtain hot-rolled steel strip; (3) After annealing, descaling, pickling and cold rolling, the hot-rolled steel strip can obtain high-hardness and wear-resistant stainless steel.

3. The method for preparing high-hardness wear-resistant stainless steel according to claim 2, characterized in that: In step (1), the smelting is carried out by a three-step method of GOR-VOD-LF; during the LF process, the total oxygen content before the addition of the Ti alloy is controlled to be ≤0.001%, the N content is ≤0.006%, and after the Ti alloy element is added, the lower electrode temperature is prohibited from being raised, and the weak stirring time is controlled to be ≥10min; the casting temperature is 1580±20°C.

4. The method for preparing high-hardness wear-resistant stainless steel according to claim 2, characterized in that: In step (2), the heating temperature is 1150°C-1190°C, the heating time is 180min-240min; the coiling temperature is 650°C-680°C; and the thickness of the hot-rolled steel strip is 3.0-6.0mm.

5. The method for preparing high-hardness wear-resistant stainless steel according to claim 2, characterized in that: In step (2), the rolling process is: the heated continuous casting billet is subjected to 7 passes of rough rolling to obtain an intermediate billet, and then the intermediate billet is subjected to 3 passes of furnace coil rolling.

6. The method for preparing high-hardness wear-resistant stainless steel according to claim 5, characterized in that: During the rough rolling process, the starting temperature is 1050℃-1100℃; the thickness of the intermediate billet is 23-28mm; during the furnace coil rolling process, the starting temperature is 980℃-1000℃ and the final rolling temperature is 800℃-850℃.

7. The method for preparing high-hardness wear-resistant stainless steel according to claim 2, characterized in that: In step (3), during the annealing process, the residual oxygen in the continuous annealing furnace is controlled to be 2%-6%, the heating section 1, the temperature control zone 1, 2 is 880±20℃; the heating section 2, the temperature control zone 3, 4 is 890±20℃; the heating section 3, the temperature control zone 5, 6 is 900±20℃; the heating section 4, the temperature control zone 7, 8 is 910±20℃; the heating section 5, the temperature control zone 9, 10 is 890±20℃. The cooling water volume P4 temperature is controlled to be 820℃±20℃, the P5 temperature is controlled to be 600±20℃, the TV value is controlled to be 80-140mm·m / min, and the P6 steel strip out of the furnace temperature is <80℃.

8. The method for preparing high-hardness wear-resistant stainless steel according to claim 2, characterized in that: In step (3), during the descaling process, the reduction amount of the dephosphorizing machine is controlled to be 70-85 mm, and the tension is controlled to be 300-350 kN; during the cold rolling process, the cumulative deformation of the cold rolling is controlled to be controlled to be 35% to 55%.

9. The method for preparing high-hardness wear-resistant stainless steel according to claim 2, characterized in that: In step (3), the pickling includes sulfuric acid pickling, primary mixed acid pickling and secondary mixed acid pickling.

10. The method for preparing high-hardness wear-resistant stainless steel according to claim 9, characterized in that: During the sulfuric acid pickling process, the acid solution used is 300-350g / L H2SO4 solution, and the iron ion concentration is ≤60g / L; the acid solution temperature is 85-95℃, and the pickling time is 55-80s; during the primary mixed acid pickling process, the acid solution used is composed of 8-150g / L HF solution and 90-110g / L HNO3 solution, the iron ion concentration is ≤40g / L, the acid solution temperature is 50-65℃, and the pickling time is 55-90s; during the secondary mixed acid pickling process, the acid solution used is composed of 14-20g / L HF solution and 90-110g / L HNO3 solution, the iron ion concentration is ≤40g / L, the acid solution temperature is 50-65℃, and the pickling time is 50-90s.

11. Use of the high-hardness and wear-resistant stainless steel according to claim 1 in the preparation of washers.

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