An antibacterial stainless steel material and a method for manufacturing the same

Abstract

The application discloses an antibacterial stainless steel material and a preparation method thereof, and relates to the technical field of stainless steel materials.Scheme: taking post-consumer stainless steel as the main raw material, after crushing, oil removal and magnetic separation, the material is returned to the furnace for smelting, supplemented by composite refining and impurity removal under vacuum induction smelting and dynamic control of composition, then a plurality of alloying elements are introduced, and through three-stage precipitation heat treatment and cold deformation annealing process, a nano-scale precipitation strengthening structure is constructed, and finally a functional stainless steel material with mechanical properties, corrosion resistance and long-acting antibacterial property is obtained.The application improves the yield strength and tensile strength; through the Nb-Ta induction mechanism, the Cu precipitation phase particle size is precisely controlled and distributed in the grain boundary and dislocation, so that the organizational stability is improved; the Cu-Mg path is adopted to realize the continuous release of metal ions, and the sterilization rate is relatively high; meanwhile, the recycled material contains a relatively high proportion, and under the premise of ensuring the performance, the raw material utilization rate is significantly improved, and the green metallurgy and sustainable manufacturing are promoted.

Description

Technical Field

[0001] This invention relates to the field of stainless steel materials technology, and in particular to an antibacterial stainless steel material and its preparation method. Background Technology

[0002] Stainless steel, due to its excellent mechanical properties, corrosion resistance, and processing performance, is widely used in various fields such as construction, medical, transportation, food, and energy. As global demands for material performance increase, multifunctional stainless steel materials are gradually becoming a research focus, especially antibacterial stainless steel, which can effectively inhibit bacterial growth and reduce the risk of cross-infection, making it an important direction in hospitals, food processing, and home kitchens and bathrooms. Simultaneously, with the large-scale use of stainless steel products, the recycling of waste materials is gradually becoming a new trend in the materials industry. Against the backdrop of increasingly scarce metallurgical resources and growing environmental pressures, how to improve the recycling efficiency of post-consumer stainless steel and achieve functional upgrades has become a key issue in the design and preparation of stainless steel materials. Furthermore, with the increasing demand for lightweight and high-strength materials, achieving excellent strength, corrosion resistance, and functional synergy in stainless steel materials under high recycling ratio conditions poses even greater challenges to traditional alloy design and metallurgical processes.

[0003] However, the preparation of functional materials based on recycled stainless steel faces multiple technical bottlenecks in the current technology. First, most post-consumer stainless steel suffers from impurity accumulation, microstructure degradation, and compositional fluctuations. Traditional recycling methods are often only used for low-value-added stainless steel castings or profiles, resulting in low recycling rates. Especially under the combined requirements of high strength and high functionality, it is difficult to meet the material standards for complex performance coupling. Second, traditional alloying designs mostly rely on conventional element systems, with strengthening methods primarily based on solid solution strengthening and precipitation strengthening. However, without precise control, precipitates are often large in size and irregularly distributed, easily accumulating at grain boundaries and inducing brittle fracture or intergranular corrosion, reducing the overall reliability of the material. In addition, existing stainless steel solutions for achieving antibacterial functions mostly employ surface coatings or surface modification methods, which suffer from poor durability, easy loss of functionality, and inability to be reprocessed. Some solutions use a single alloying element as the antibacterial agent, whose precipitation behavior is difficult to control stably and is also prone to increased corrosion sensitivity due to coarsening or uneven distribution of particles. In addition, in terms of heat treatment process, most solutions adopt a single-stage or two-stage precipitation heat treatment path, lacking a precise stage control mechanism, and cannot simultaneously achieve the synergistic effect of multiple target performances such as high strength, corrosion resistance and antibacterial properties, resulting in significant mutual exclusion issues between performances.

[0004] Furthermore, in terms of intergranular corrosion control, existing recycled stainless steel materials often suffer from uneven grain boundary precipitation and localized chromium depletion due to factors such as uncontrollable elemental ratios and unreasonable heat treatment regimes. This leads to decreased passivation film stability and makes the materials difficult to pass corrosion resistance tests. In particular, the control path for achieving refined precipitation and uniform microstructure in complex alloy systems remains unclear, and there is a lack of systematic strengthening and corrosion resistance schemes under high-proportion recycled material usage conditions. Therefore, how to overcome the performance uncertainty caused by compositional fluctuations through microstructure and precipitation control under the premise of high recycling ratios, while constructing a stable and effective multifunctional synergistic mechanism, is a major challenge in current stainless steel recycled material research.

[0005] The paper "Corrosion-resistant and antibacterial austenitic stainless steel alloy pipe for direct drinking water and its heat treatment method" discloses an alloy design scheme that achieves antibacterial function by adding about 2.5-4.5 wt% Cu element and combining it with a special heat treatment process (CN110904386A).

[0006] While this approach imparts good antibacterial properties to the material, its high copper content and lack of precise control over Cu precipitate particle size result in a trade-off between strengthening and corrosion resistance. Furthermore, it fails to disclose the microstructure stability and impurity control pathways under high-proportion recycled raw material conditions, limiting its improvement in pitting potential. Its strengthening effect and long-term stability require further optimization. Patent CN104480407A proposes a method for preparing antibacterial stainless steel containing copper and cerium, which synergistically improves oxidation and corrosion resistance through Ce and possesses certain antibacterial activity. Although auxiliary elements are introduced to improve corrosion resistance, this approach lacks a precise time-sequential control mechanism for the precipitate structure. The precipitates tend to aggregate at grain boundaries and exhibit uneven size distribution, still posing risks of decreased corrosion resistance and intergranular sensitivity during hot deformation processing and in humid environments. Furthermore, Chinese standards (GB / T) and group standards have verified the antibacterial and corrosion-resistant properties of Cu-containing stainless steel in medical implant materials, particularly 316LCu. However, these documents and standards often use commercially available raw materials or small-proportion Ti / Ni / Cu alloy systems, and their durability release mechanisms and high-proportion alloy systems combined with recycled materials have not been fully verified. These solutions typically rely on high-cost raw materials or complex post-processing procedures, and their capacity for large-scale recycling of materials remains limited.

[0007] In summary, existing technologies still struggle to address the following key issues: First, achieving simultaneous improvement in the strength, toughness, and corrosion resistance of stainless steel materials under high recycling ratios; second, avoiding intergranular corrosion caused by impurity accumulation and improper precipitation behavior, maintaining the interface integrity and passivation film stability of the material; third, constructing a long-term effective antibacterial system to ensure the stable release of metal ions without affecting corrosion resistance; and fourth, developing heat treatment pathways adaptable to complex composition systems to achieve controllable precipitation of strengthening phases and stable microstructure. Therefore, there is an urgent need to propose a systematic alloying and microstructure control technology designed specifically for the characteristics of post-consumer stainless steel materials, overcoming the functional performance conflicts in existing technologies, and ensuring the stable realization of the material's mechanical properties, corrosion resistance, and antibacterial properties while improving recycling rates. Summary of the Invention

[0008] To achieve the above-mentioned objectives and address the aforementioned technical problems, this invention provides an antibacterial stainless steel material and its preparation method, comprising the following steps:

[0009] (1) After being crushed, degreased and magnetically separated, the stainless steel is recycled as a raw material for stainless steel smelting.

[0010] Preferably, the stainless steel raw material is post-consumer austenitic or martensitic stainless steel, which is generated during its original use due to aging or mechanical scrapping, and has good recycling value.

[0011] Preferably, the stainless steel raw material accounts for 50-75% of the total raw material mass and can be used in conjunction with conventional electrolytic nickel or electrolytic chromium to achieve flexible composition control and cost reduction.

[0012] (2) The stainless steel raw material is melted in a vacuum induction melting furnace to form a melt.

[0013] Preferably, under the condition that the melt temperature is controlled at 1600℃~1650℃, a composite refining slag with a mass of 2.5%~3.5% of the melt mass is added for vigorous stirring and refining to effectively remove impurity elements and improve the purity of the parent material.

[0014] Preferably, the composite refining slag is composed of calcium oxide, magnesium oxide, aluminum oxide, and calcium fluoride mixed in a mass ratio of 4:2:3:1. Subsequently, the content of its main elements is analyzed by intermediate sampling, and nickel-iron alloy and ferrochrome alloy are added according to the test results. The chromium content is dynamically adjusted to 16%–20% and the nickel content to 8%–12%, laying the foundation for the subsequent introduction of alloying elements and microstructure control.

[0015] (3) After argon gas is introduced into the surface of the melt to form a protective atmosphere, niobium powder and tantalum powder are added and fully alloyed.

[0016] Preferably, the argon gas introduction rate is 20–30 L / min·m² to avoid oxidation loss of highly reactive elements at high temperatures. Preferably, the niobium powder accounts for 0.3%–0.5% of the melt mass, the tantalum powder accounts for 0.1%–0.3% of the melt mass, and the total mass of niobium and tantalum powders does not exceed 0.6%. The Nb and Ta can form stable carbides / nitrides and serve as nucleation cores for nano-precipitates, enhancing the control of Cu precipitation and the stability of the microstructure.

[0017] Subsequently, the melt was cooled to 1400℃, and under the protection of argon gas, cerium powder, aluminum powder and copper-magnesium alloy were added in sequence and stirred and homogenized for 15 to 20 minutes.

[0018] Preferably, cerium powder accounts for 0.02% to 0.03% of the melt mass, and aluminum powder accounts for 0.05% to 0.1% of the melt mass; in the copper-magnesium alloy, the pure copper content, converted to pure copper, accounts for 0.8% to 1.2% of the melt mass, with a particle size controlled at 1 to 5 mm, and the magnesium content is 8 to 12 wt%. Cu, as the main antibacterial element, can precipitate nano-Cu particles under Nb control during subsequent heat treatment; Ce, as a rare earth element, assists in purifying inclusions and improving grain boundary activity, while synergistically improving hot-rolling plasticity with Al; Mg further enhances the uniformity of the alloy composition in the solid solution state, avoiding the formation of coarse phases.

[0019] (4) The homogenized melt is poured into a preheated mold to obtain a steel ingot.

[0020] Preferably, the pouring temperature is controlled at 1500℃, and the mold preheating temperature is between 200 and 400℃, in order to avoid excessive temperature difference leading to macroscopic cracks.

[0021] (5) The steel ingot is subjected to multiple hot forging passes, with the final forging temperature controlled at 950-1000℃, followed by hot rolling. The final hot rolling temperature is controlled between 800-850℃, and then air-cooled to room temperature. This plastic processing path is beneficial for refining grains, distributing precipitates, enhancing the uniformity of the microstructure, and improving the synergistic stability of the material's antibacterial and mechanical properties.

[0022] (6) The obtained plate is subjected to a three-stage heat treatment, including: a) a pre-stabilization treatment at 600-630℃ for 2 hours, which is used to initially precipitate some metastable phases and release lattice distortion stress;

[0023] b) Main precipitation treatment at 750℃ for 1 hour promotes the directional precipitation of Cu nano-precipitates at Nb / Ta induction sites and their distribution near grain boundaries;

[0024] c) After cold deformation is applied to the material, it is annealed and stabilized at 450-500°C for 1-2 hours.

[0025] Preferably, the cold deformation is a single-pass cold rolling along the rolling direction, with a deformation amount of 30-50%. This step enhances the dislocation density and increases the driving force for Cu precipitation on the one hand, and controls the size and distribution of precipitated particles through stabilizing annealing on the other hand, effectively balancing antibacterial properties and mechanical properties.

[0026] The present invention also provides an antibacterial stainless steel material, characterized in that the antibacterial stainless steel material is prepared by the above-described preparation method.

[0027] The beneficial effects of the technical solution provided by this invention are as follows:

[0028] 1. This invention effectively regulates Cu precipitation behavior by constructing an Nb-Ta synergistic induction mechanism, ensuring stable control of the precipitated phase size and uniform dispersion around grain boundaries and dislocations. This structure significantly enhances the yield strength and tensile strength of the material, with an overall increase of over 20%, while maintaining or exceeding the original standard of 304 stainless steel in tensile strength, demonstrating the high effectiveness of this multi-component microalloying system in improving mechanical properties.

[0029] 2. The three-stage precipitation heat treatment path adopted in this invention includes pre-stabilization treatment, main precipitation treatment, and post-cold rolling stabilization treatment. This approach can precisely induce the sequential precipitation of Cu-based precipitates, strengthen the spatial distribution and interfacial bonding of second-phase particles, and avoid intergranular embrittlement. While achieving strengthening, the pitting potential is significantly increased (by approximately 100 mV), and the pitting current density is significantly reduced, indicating that it maintains the excellent corrosion resistance of stainless steel and possesses good passivation film stability, significantly superior to traditional single-stage or two-stage treatment methods.

[0030] 3. Achieving Cu through the introduction path of Cu-Mg alloy. 2+ The slow-release regulation, combined with the stable Nb / Ta precipitation mechanism, can maintain the metal ion release concentration continuously within a 60-day cycle, exhibiting excellent long-lasting antibacterial activity. Antibacterial testing verified that the material consistently maintains a kill rate of over 99.5% against Escherichia coli and Staphylococcus aureus, with a long-lasting and repeatable antibacterial effect.

[0031] 4. This alloy system allows for a high proportion of post-consumer stainless steel recycled materials (up to 75%) as raw materials. After refining, impurity removal and microalloying, it still maintains excellent mechanical and corrosion resistance properties, indicating that the design has strong element reuse and homogenization capabilities in the metallurgical process, which is conducive to green manufacturing and sustainable performance optimization. Attached Figure Description

[0032] Figure 1 Photographs of Escherichia coli colonies after 48 hours of culture for the embodiments and comparative examples of the present invention: a. Example 1; b. Example 6; c. Comparative Example 2; d. Comparative Example 1; e. Comparative Example 5; f. Comparative Example 3;

[0033] Figure 2 Photographs of Staphylococcus aureus bacterial colonies after 48 hours of culture for the embodiments and comparative examples of the present invention: a. Example 1; b. Example 6; c. Comparative Example 2; d. Comparative Example 1; e. Comparative Example 5; f. Comparative Example 3;

[0034] Figure 3 Photographs of bacterial colonies after 60 days of culture in Example 1 of this invention: a) Escherichia coli; b) Staphylococcus aureus;

[0035] Figure 4 FE-SEM morphology images of the antibacterial phase precipitated in the matrix of the embodiments and comparative examples of the present invention: (a) Example 1; (b) Comparative Example 5; (c) Comparative Example 3;

[0036] Figure 5 This is an optical tissue photograph of Embodiment 1 of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0038] Example 1

[0039] (1) Pretreatment and proportioning of stainless steel raw materials

[0040] Post-consumer austenitic stainless steel (grade 304) derived from waste materials was selected as the recycling raw material.

[0041] Preprocessing flow:

[0042] Break into pieces ≤50mm;

[0043] Three-stage ultrasonic degreasing (solvent: acetone, temperature 60℃, duration 30min).

[0044] Strong magnetic separation (magnetic field strength 1.2T) removes non-ferromagnetic impurities;

[0045] The recycled stainless steel raw materials account for 65% of the total raw material mass.

[0046] (2) Smelting and refining to remove impurities

[0047] The above raw materials are fed into a vacuum induction melting furnace with a vacuum degree ≤5Pa, and melted at 1600℃ to form an initial melt.

[0048] A composite refining slag, comprising calcium oxide, magnesium oxide, aluminum oxide, and calcium fluoride, at a mass ratio of 4:2:3:1, is added to the melt. High-speed electromagnetic stirring is then used for refining to remove impurities such as sulfur (S), phosphorus (P), and silicon (Si).

[0049] After intermediate sampling and analysis, nickel-iron alloy and ferrochrome alloy were added to adjust the Cr content in the melt to 18% and the Ni content to 10%.

[0050] (3) Alloying and homogenization treatment of functional elements

[0051] Argon gas was introduced into the surface of the melt at a flow rate of 25 L / min·m² to create a protective atmosphere. Then, alloying elements were added sequentially:

[0052] The amount of niobium powder added is 0.4% of the melt mass;

[0053] The amount of tantalum powder added is 0.2% of the melt mass;

[0054] The two materials were alloyed under argon protection for 10 minutes.

[0055] The melt was cooled to 1400℃, and under argon protection, the following were added sequentially:

[0056] Cerium powder: 0.025% of the melt mass; Aluminum powder: 0.08% of the melt mass;

[0057] Copper-magnesium alloy: 1.0% pure copper added, equivalent to the melt mass, with a Mg content of 10 wt% and a particle size controlled at 2–3 mm.

[0058] Continue homogenizing and stirring for 20 minutes to ensure that all alloying elements are fully dissolved, dispersed, and uniformly dissolved in the melt, thus pre-setting their subsequent precipitation behavior.

[0059] (4) Casting into ingots

[0060] The homogenized melt was poured into a graphite-coated ceramic mold preheated to 300°C at 1500°C to obtain a crack-free, dense steel ingot.

[0061] (5) Hot forging and hot rolling

[0062] The steel ingot is heated to 1200℃ and held at that temperature for multiple hot forging passes, with the final forging temperature controlled at 980℃.

[0063] The material was then hot-rolled at a final rolling temperature of 840°C, followed by air cooling to room temperature to obtain a hot-rolled sheet with a thickness of 3 mm.

[0064] (6) Three-stage heat treatment process

[0065] a) Pre-stabilization treatment: Keep at 620℃ for 2 hours;

[0066] b) Main precipitation treatment: keep at 750℃ for 1 hour;

[0067] c) Stabilization treatment: The sheet is cold rolled in a single pass along the rolling direction with a deformation of 40%, and then annealed at 450°C for 1 hour.

[0068] Example 2

[0069] Prepared using the same method as in Embodiment 1, except that recycled stainless steel raw materials account for 50% of the total raw material mass.

[0070] Example 3

[0071] Prepared using the same method as in Embodiment 1, except that recycled stainless steel raw materials account for 75% of the total raw material mass.

[0072] Example 4

[0073] Prepared using the same method as in Embodiment 1, except that the amount of composite refining slag added is 2.5% of the melt mass.

[0074] Example 5

[0075] Prepared using the same method as in Embodiment 1, except that the amount of composite refining slag added is 3.5% of the melt mass.

[0076] Example 6

[0077] Prepared using the same method as in Embodiment 1, except that the total mass of niobium powder and tantalum powder is 0.6%.

[0078] Example 7

[0079] Prepared using the same method as in Example 1, except that the amount of copper added (equivalent to pure copper) is 0.8%.

[0080] Example 8

[0081] Prepared using the same method as in Example 1, except that the amount of copper added (equivalent to pure copper) is 1.2%.

[0082] Example 9

[0083] The Cu-Mg alloy was prepared using the same method as in Example 1, except that the magnesium content in the Cu-Mg alloy was 8 wt%.

[0084] Example 10

[0085] The Cu-Mg alloy was prepared using the same method as in Example 1, except that the magnesium content in the Cu-Mg alloy was 12 wt%.

[0086] Example 11

[0087] Prepared using the same method as in Embodiment 1, except that the cold rolling deformation is 30%.

[0088] Example 12

[0089] Prepared using the same method as in Embodiment 1, except that the cold rolling deformation is 50%.

[0090] Example 13

[0091] Prepared using the same method as in Embodiment 1, except that recycled post-consumer martensitic stainless steel (3Cr13 grade) was selected as the raw material.

[0092] Comparative Example 1

[0093] Prepared using the same method as in Embodiment 1, except that niobium powder is replaced with tantalum powder.

[0094] Comparative Example 2

[0095] Prepared using the same method as in Embodiment 1, except that tantalum powder is replaced with niobium powder.

[0096] Comparative Example 3

[0097] Prepared using the same method as in Embodiment 1, except that tantalum powder and niobium powder are not added.

[0098] Comparative Example 4

[0099] Prepared using the same method as in Example 1, except that the Cu-Mg alloy is replaced with pure copper powder.

[0100] Comparative Example 5

[0101] Prepared using the same preparation method as in Implementation 1, except that a single-stage heat treatment process is used in step (6): holding at 650℃ for hours.

[0102] Comparative Example 6

[0103] Prepared according to the same preparation method as in Implementation 1, except that a two-stage heat treatment process is used in step (6): heat treatment at 750°C for 2 hours;

[0104] The sheet metal was subjected to single-pass cold rolling along the rolling direction with a deformation of 40%, followed by annealing at 450°C for 1 hour.

[0105] Experimental test:

[0106] 1. Antibacterial performance test:

[0107] The antibacterial properties of the antibacterial stainless steel material of this invention were tested according to the improved standard method of JIS Z 2801-2000. The specific steps are as follows:

[0108] (1) Sample preparation: The prepared sample was processed into a size of 30 mm × 30 mm × 1 mm, and then sanded and polished with sandpaper in stages and mechanically polished. Then, it was ultrasonically cleaned with acetone at 60°C for 20 minutes, dried, and then sterilized with high pressure steam at 121°C for 20 minutes for later use.

[0109] (2) Preparation of bacterial suspension: Escherichia coli and Staphylococcus aureus were selected as test strains. After culturing for 24 h, bacterial suspension was prepared with sterile physiological saline at a concentration of 5 × 10⁻⁶. 4 CFU / mL.

[0110] (3) Antibacterial procedure: Add 20 μL of bacterial solution to the surface of the sterilized sample, and then cover it with a 20 mm × 20 mm sterilized polyethylene film. Place the sample in a constant temperature incubator with relative humidity RH>90% and temperature 37±1℃ for 24±1 hours.

[0111] (4) Elution of bacterial solution: After culturing, place the sample in a sterile petri dish containing 20 mL of sterile physiological saline and shake thoroughly to elute the bacterial cells. Take 100 μL of the eluent and spread it evenly on a nutrient agar plate.

[0112] (5) Culture and Counting: Plates were incubated at 37°C for 24 hours, and the colony count (CFU) was recorded. 304 stainless steel without added antibacterial elements was used as the control group. The antibacterial rate R was calculated as follows: R = (BA)B × 100%

[0113] Wherein, B is the colony count of the control sample, and A is the colony count of the sample of the present invention.

[0114] 2. Mechanical property testing

[0115] The test shall be conducted in accordance with GB / T 228.1-2021 "Metallic materials, tensile testing - Part 1: Test method at room temperature".

[0116] 3. Pitting resistance test

[0117] GB / T 18997.1-2003 "Determination of pitting potential in metals and alloys – Part 1: Test method for evaluating the pitting resistance of stainless steel"

[0118] Table 1 Mechanical Performance Test Data

[0119]

[0120] Table 2 Pitting Potential Test Data

[0121]

[0122] From Table 1, Table 2, and Figure 1-5 As can be seen, the stainless steel materials shown in the embodiments of the present invention all exhibit superior comprehensive performance compared to the original 304 stainless steel. In Example 1, while the yield strength and tensile strength are significantly improved, the pitting corrosion potential is significantly increased and the pitting corrosion current density is significantly reduced, indicating that it maintains good corrosion resistance while being strengthened, and no tendency for intergranular corrosion is observed. This improvement is mainly attributed to the synergistic induction of Cu precipitation by Nb and Ta to form nanoprecipitates with a particle size in the range of 10–50 nm. These nanoprecipitates are stably distributed at dislocations or grain boundaries, which not only improve mechanical properties but also continuously release Cu. 2+ This invention achieves long-lasting antibacterial effects. Bacterial culture dish photographs show sparse and uniformly distributed colonies. Combined with the aforementioned precipitation regulation and Cu-Mg alloy doping mechanism, its kill rate against Escherichia coli and Staphylococcus aureus exceeds 99.5%, and the antibacterial effect is maintained even after 60 days. In contrast, in each comparative example, removing Nb or Ta individually, replacing the Cu-Mg alloy, or using a simplified heat treatment path all resulted in decreased mechanical properties, decreased pitting potential, or increased current density. This indicates that the combination of key elements and the heat treatment regime play a decisive role in improving the performance of this invention. Therefore, this invention constructs a new stainless steel material system with high strength, corrosion resistance, and long-lasting antibacterial effects through multi-component alloying, composite precipitation regulation mechanism, and a three-stage heat treatment technology path.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an antibacterial stainless steel material, characterized in that, Includes the following steps: (1) After being crushed, degreased, and magnetically separated, the post-consumer stainless steel is recycled as a raw material for stainless steel smelting. The stainless steel raw material accounts for 50-75% of the total raw material mass; (2) The stainless steel raw material is melted in a vacuum induction melting furnace to form a melt. Composite refining slag is added and stirred to refine the material, remove impurities, and nickel-iron alloy and ferrochrome alloy are added through intermediate sampling analysis to adjust the chromium content to 16% to 20% and the nickel content to 8% to 12%. The composite refining slag is composed of calcium oxide, magnesium oxide, aluminum oxide and calcium fluoride mixed in a mass ratio of 4:2:3:1, and the amount added accounts for 2.5% to 3.5% of the melt mass. (3) After argon gas is introduced into the surface of the melt to form a protective atmosphere, niobium powder and tantalum powder are added and fully alloyed. Then the melt is cooled to 1400℃, and cerium powder, aluminum powder and copper-magnesium alloy are added in sequence and homogenized and stirred for 15 to 20 minutes. The niobium powder accounts for 0.3% to 0.5% of the melt mass, the tantalum powder accounts for 0.1% to 0.3% of the melt mass, and the total mass of niobium powder and tantalum powder is ≤0.6%. The powder constitutes 0.02% to 0.03% of the melt mass, the aluminum powder constitutes 0.05% to 0.1% of the melt mass, and the copper-magnesium alloy is added in an amount equivalent to 0.8% to 1.2% of the melt mass of pure copper. The copper-magnesium alloy has a particle size of 1–5 mm and a magnesium content of 8–12 wt%. (4) The homogenized melt is poured into a preheated mold to obtain a steel ingot; (5) The steel ingot is hot forged in multiple passes and then hot rolled. The final rolling temperature is 950-1000℃, and then air-cooled to room temperature. (6) The obtained sheet material is subjected to a three-stage heat treatment, including: a) Pre-stabilization treatment with heat preservation at 600-630℃ for 2 hours; b) Main precipitation treatment with heat treatment at 750℃ for 1 hour; c) After cold deformation is applied to the material, it is annealed and stabilized at 450-500°C for 1-2 hours.

2. The method for preparing the antibacterial stainless steel material according to claim 1, characterized in that, The stainless steel raw material is derived from post-consumer austenitic or martensitic stainless steel.

3. The method for preparing the antibacterial stainless steel material according to claim 1, characterized in that, In step (3), argon gas is introduced to protect the surface of the melt, with a flow rate of 20–30 L / (min·m). 2 ).

4. The method for preparing the antibacterial stainless steel material according to claim 1, characterized in that, In step (6), the cold deformation is a single-pass cold rolling along the rolling direction, with a deformation amount of 30-50%.

5. An antibacterial stainless steel material, characterized in that, The antibacterial stainless steel material is prepared by any one of the preparation methods of claims 1-4.

Images