Low-cost, high-strength and high-toughness stainless steel for ophthalmologic scalpel and preparation method of stainless steel

Abstract

The invention belongs to the technical field of stainless steel, and particularly relates to low-cost high-strength toughness stainless steel for an ophthalmic scalpel and a preparation method of the stainless steel, the content of a precious element Ni is reduced, the content of a Cu element is increased, and the low-cost high-strength toughness stainless steel for the ophthalmic scalpel is obtained through the production process of hot rolling, solid solution, cold rolling, annealing, cold rolling and annealing. The yield strength of the finally produced stainless steel is larger than or equal to 930 MPa, the tensile strength of the finally produced stainless steel is larger than or equal to 1130 MPa, the ductility of the finally produced stainless steel is larger than or equal to 28%, the requirement for machining and application of ophthalmic surgical tools can be met, and cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel, in particular to low-cost high-strength and toughness stainless steel for ophthalmic surgical knives and a preparation method thereof. Background Art

[0002] Disposable ophthalmic scalpels are essential tools for ophthalmic microsurgery. Their quality plays a key role in the postoperative effect of ophthalmic surgery, because the sharpness of the scalpel and the size of the incision will affect the degree of surgical astigmatism. However, there are many problems with this type of surgical instrument on the market. The design process is rough, the quality is low, and the toughness is insufficient, which brings a lot of inconvenience to doctors. Moreover, most ophthalmic scalpels are now made of martensitic stainless steel, the production process is inefficient, and the cost is high, which poses a great cost problem for both manufacturers and patients.

[0003] Martensitic stainless steel for surgical knives, representative of which is SUS420J2, is an excellent stainless steel material. It is usually used to manufacture sharp knives, blades, medical devices and other products with high hardness and corrosion resistance. The main components of SUS420J2 include chromium (Cr) and molybdenum (Mo), a small amount of nickel (Ni), manganese (Mn) and silicon (Si) and other elements. It has excellent hardness and corrosion resistance, better cutting performance than general stainless steel, and is suitable for making some products that require cutting performance. At the same time, it also has excellent heat resistance and wear resistance, and can be used for a long time under high temperature and high pressure without failure. However, this martensitic stainless steel has added more expensive alloy elements, has a high cost, and requires aging heat treatment, and has high processing costs. Therefore, it is of great practical value to develop a low-cost, high-strength and tough stainless steel for ophthalmic surgical knives and a preparation method thereof. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the main purpose of the present invention is to provide a low-cost, high-strength and toughness stainless steel for ophthalmic surgical knives and a preparation method thereof.

[0005] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0006] A method for preparing low-cost, high-strength and high-toughness stainless steel for ophthalmic surgical knives comprises the following steps:

[0007] S1. Smelting to obtain a stainless steel ingot; the Cu content of the stainless steel is 1.0-1.5wt%, and the Ni content is 7.0-8.0wt%;

[0008] S2. After the ingot is kept at 1230-1250°C for 2-3 hours, it is immediately hot-rolled to obtain a plate;

[0009] S3, the plate is subjected to solution treatment at a temperature of 1050-1100°C for 2-3 hours, and is immediately cooled after the treatment, and then the surface oxide scale is removed;

[0010] S4, the plate after solution treatment is subjected to multiple cold rolling to obtain a cold rolled plate A;

[0011] S5, the cold-rolled sheet A is annealed and then air-cooled to room temperature; the annealing temperature is 500-650°C, and the annealing time is 10-100 min;

[0012] S6, the cold-rolled sheet A after annealing is subjected to multiple cold rolling passes to obtain a cold-drawn sheet B;

[0013] S7. The cold-drawn sheet B is annealed and then air-cooled to room temperature; the annealing temperature is 200-250° C. and the annealing time is 100-180 min, thereby obtaining low-cost, high-strength and toughness stainless steel for ophthalmic surgical knives.

[0014] As a preferred embodiment of the method for preparing low-cost, high-strength and toughness stainless steel for ophthalmic scalpels described in the present invention, in step S1, the raw materials are melted in a vacuum induction furnace and then cast to obtain a stainless steel ingot, and the ingot is air-cooled to room temperature before riser removal and surface peeling.

[0015] As a preferred embodiment of the method for preparing low-cost, high-strength and high-toughness stainless steel for ophthalmic surgical knives described in the present invention, wherein: in step S2, the starting rolling temperature is ≥1100°C, and the final rolling temperature is ≥900°C.

[0016] As a preferred solution of the method for preparing low-cost, high-strength and toughness stainless steel for ophthalmic surgical knives described in the present invention, wherein: in the step S2, the reduction amount of a single hot rolling pass is less than 30%, and the total reduction amount is more than 70%.

[0017] As a preferred solution of the method for preparing low-cost, high-strength and toughness stainless steel for ophthalmic surgical knives described in the present invention, wherein: in the step S4, the cold rolling reduction in a single pass is less than 20%, and the total cold rolling reduction is more than 50%.

[0018] As a preferred solution of the method for preparing low-cost, high-strength and toughness stainless steel for ophthalmic surgical knives described in the present invention, wherein: in the step S6, the cold rolling reduction in a single pass is less than 20%, and the total cold rolling reduction is more than 70%.

[0019] To solve the above technical problem, according to another aspect of the present invention, the present invention provides the following technical solution:

[0020] A low-cost high-strength and high-toughness stainless steel for ophthalmic surgical knives is prepared by adopting the above-mentioned method for preparing the low-cost high-strength and high-toughness stainless steel for ophthalmic surgical knives.

[0021] As a preferred embodiment of the low-cost, high-strength and high-toughness stainless steel for ophthalmic scalpels described in the present invention, the yield strength of the low-cost, high-strength and high-toughness stainless steel for ophthalmic scalpels is ≥930MPa, the tensile strength is ≥1130MPa, and the elongation is ≥28%.

[0022] As a preferred embodiment of the low-cost, high-strength and high-toughness stainless steel for ophthalmic scalpels described in the present invention, the composition of the low-cost, high-strength and high-toughness stainless steel for ophthalmic scalpels, in terms of mass percentage, includes: C≤0.18wt%, Si≤1.0wt%, S≤0.03wt%, P≤0.02wt%, Mn2.0~3.0wt%, Cr 17.0~18.0wt%, Ni 7.0~8.0wt%, Cu 1.0~1.5wt%, and the rest is Fe and unavoidable impurities.

[0023] The beneficial effects of the present invention are as follows:

[0024] The invention provides a low-cost, high-strength and tough stainless steel for ophthalmic surgical knives and a preparation method thereof, wherein the content of the precious element Ni is reduced and the content of the element Cu is increased. The stainless steel having a precipitated nano-scale copper-rich phase and coexistence of martensite and austenite is produced by adopting a production process of hot rolling, solid solution, cold rolling, annealing, cold rolling and annealing. The yield strength of the stainless steel finally produced is ≥930MPa, the tensile strength is ≥1130MPa, and the elongation is ≥28%, which can meet the processing application of ophthalmic surgical knives and has low cost. DETAILED DESCRIPTION

[0025] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] According to one aspect of the present invention, the present invention provides the following technical solution:

[0027] A method for preparing low-cost, high-strength and high-toughness stainless steel for ophthalmic surgical knives comprises the following steps:

[0028] S1. Smelting to obtain a stainless steel ingot; the Cu content of the stainless steel is 1.0-1.5wt%, and the Ni content is 7.0-8.0wt%;

[0029] S2. After the ingot is kept at 1230-1250°C for 2-3 hours, it is immediately hot-rolled to obtain a plate;

[0030] S3, the plate is subjected to solution treatment at a temperature of 1050-1100°C for 2-3 hours, and immediately oil-cooled or water-cooled after the treatment, and then the surface oxide scale is removed;

[0031] S4, the plate after solution treatment is subjected to multiple cold rolling to obtain a cold rolled plate A;

[0032] S5, the cold-rolled sheet A is annealed and then air-cooled to room temperature; the annealing temperature is 500-650°C, and the annealing time is 10-100 min;

[0033] S6, the cold-rolled sheet A after annealing is subjected to multiple cold rolling passes to obtain a cold-drawn sheet B;

[0034] S7. The cold-drawn sheet B is annealed and then air-cooled to room temperature; the annealing temperature is 200-250° C. and the annealing time is 100-180 min, thereby obtaining low-cost, high-strength and toughness stainless steel for ophthalmic surgical knives.

[0035] The invention reduces the content of precious element Ni in stainless steel and increases the content of Cu element, and produces stainless steel with precipitated nano-scale copper-rich phase and coexistence of martensite and austenite by adopting the production process of hot rolling, solid solution, cold rolling, annealing, cold rolling and annealing.

[0036] Preferably, in step S1, the raw material is melted in a vacuum induction furnace and then cast to obtain a stainless steel ingot, and the ingot is air-cooled to room temperature before riser removal and surface peeling.

[0037] Preferably, in step S2, the starting rolling temperature is ≥1100°C, and the finishing rolling temperature is ≥900°C.

[0038] Preferably, in step S2, the reduction in a single hot rolling pass is less than 30%, and the total reduction is above 70%, so as to ensure that the as-cast structure is completely broken up and the structure is uniform.

[0039] Preferably, in step S4, the cold rolling reduction in a single pass is less than 20%, and the total cold rolling reduction is above 50%. Preferably, the total cold rolling reduction is 50-60%.

[0040] Preferably, in step S6, the cold rolling reduction in a single pass is less than 20%, and the total cold rolling reduction is above 70%. Preferably, the total cold rolling reduction is 70-80%.

[0041] According to another aspect of the present invention, the present invention provides the following technical solution:

[0042] A low-cost high-strength and high-toughness stainless steel for ophthalmic surgical knives is prepared by adopting the above-mentioned method for preparing the low-cost high-strength and high-toughness stainless steel for ophthalmic surgical knives.

[0043] Preferably, the yield strength of the low-cost, high-strength and toughness stainless steel for ophthalmic surgical knives is ≥930 MPa, the tensile strength is ≥1130 MPa, and the elongation is ≥28%.

[0044] Preferably, the composition of the high-strength and toughness stainless steel for ophthalmic scalpels, measured in mass percentage, includes: C≤0.18wt%, Si≤1.0wt%, S≤0.03wt%, P≤0.02wt%, Mn2.0-3.0wt%, Cr 17.0-18.0wt%, Ni 7.0-8.0wt%, Cu 1.0-1.5wt%, and the rest is Fe and unavoidable impurities.

[0045] C: The C element can achieve the purpose of solid solution strengthening by forming interstitial solid solution, adjust the hardness and strength of the material, and does not affect the processing performance of stainless steel.

[0046] Cr: Cr is used to increase the corrosion resistance and improve the oxidation resistance of stainless steel.

[0047] Ni: Ni is used to improve the corrosion resistance of materials and increase the strength and toughness of structures. It has a positive effect on the matching of strength and plasticity. However, Ni is one of the more expensive alloy elements. Reducing the Ni content can significantly reduce costs. Therefore, the Ni content is controlled at 7.0-8.0wt% after comprehensive consideration.

[0048] Mn: Mn is used to improve the toughness and strength of the material, and can achieve the effect of processing strengthening in the subsequent cold working process. In addition, Mn has a strong affinity with S, and it is easy to form MnS, thereby reducing the harmful effects of S in steel.

[0049] Cu: The addition of Cu is beneficial to improve the strength and wear resistance of steel, and can also improve the antibacterial properties of the material. However, excessive copper is prone to copper brittleness and deteriorates the processing properties of the material. Too low a Cu content will weaken the antibacterial effect of stainless steel. Therefore, the Cu content should be controlled at 1.0-1.5wt% to ensure a balance between formability and corrosion resistance.

[0050] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0051] The chemical compositions of the stainless steels of the embodiments of the present invention and the comparative examples are shown in Table 1.

[0052] Table 1 Chemical composition of stainless steel in various embodiments and comparative examples (wt%)

[0053]

[0054] The main production process parameters of the stainless steel of each embodiment of the present invention and the comparative example are shown in Table 2.

[0055] Table 2 Production process parameters of stainless steel in various embodiments and comparative examples

[0056]

[0057] According to GB / T228.1-2021 "Metallic Materials Tensile Test Part 1: Room Temperature Test Method", standard tensile test specimens were prepared and then subjected to room temperature mechanical testing. The properties of the stainless steel of each embodiment of the present invention and the comparative example are shown in Table 3.

[0058] Table 3 Properties of stainless steel in various embodiments and comparative examples

[0059]

[0060]

[0061] The present invention reduces the content of the precious element Ni and increases the content of the Cu element. By adopting the production process of hot rolling, solid solution, cold rolling, annealing, cold rolling and annealing, stainless steel with precipitated nano-scale copper-rich phase and coexistence of martensite and austenite is produced. The yield strength of the stainless steel finally produced is ≥930MPa, the tensile strength is ≥1130MPa, and the elongation is ≥28%, which can meet the processing application of ophthalmic surgical knives and has low cost.

[0062] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing low-cost, high-strength and high-toughness stainless steel for ophthalmic surgical knives, characterized in that: The steps include: S1. Smelting to obtain a stainless steel ingot; the Cu content of the stainless steel is 1.0-1.5wt%, and the Ni content is 7.0-8.0wt%; S2. After the ingot is kept at 1230-1250°C for 2-3 hours, it is immediately hot-rolled to obtain a plate; S3, the plate is subjected to solution treatment at a temperature of 1050-1100°C for 2-3 hours, and is immediately cooled after the treatment, and then the surface oxide scale is removed; S4, the plate after solution treatment is subjected to multiple cold rolling to obtain a cold rolled plate A; S5, the cold-rolled sheet A is annealed and then air-cooled to room temperature; the annealing temperature is 500-650°C, and the annealing time is 10-100 min; S6, the cold-rolled sheet A after annealing is subjected to multiple cold rolling passes to obtain a cold-drawn sheet B; S7. The cold-drawn sheet B is annealed and then air-cooled to room temperature; the annealing temperature is 200-250° C. and the annealing time is 100-180 min, thereby obtaining low-cost, high-strength and toughness stainless steel for ophthalmic surgical knives.

2. The method for preparing low-cost, high-strength and high-toughness stainless steel for ophthalmic surgical knives according to claim 1, characterized in that: In step S2, the starting rolling temperature is ≥1100°C, and the finishing rolling temperature is ≥900°C.

3. The method for preparing low-cost, high-strength and high-toughness stainless steel for ophthalmic surgical knives according to claim 1, characterized in that: In the step S2, the hot rolling reduction in a single pass is less than 30%, and the total hot rolling reduction is more than 70%.

4. The method for preparing low-cost, high-strength and high-toughness stainless steel for ophthalmic surgical knives according to claim 1, characterized in that: In the step S4, the cold rolling reduction in a single pass is less than 20%, and the total cold rolling reduction is more than 50%.

5. The method for preparing low-cost, high-strength and high-toughness stainless steel for ophthalmic surgical knives according to claim 1, characterized in that: In the step S6, the cold rolling reduction in a single pass is less than 20%, and the total cold rolling reduction is more than 70%.

6. A low-cost, high-strength and tough stainless steel for ophthalmic surgical knives, characterized in that: The stainless steel is prepared by the method for preparing low-cost, high-strength and high-toughness stainless steel for ophthalmic surgical knives as described in any one of claims 1 to 5.

7. The low-cost, high-strength and high-toughness stainless steel for ophthalmic surgical knives according to claim 6, characterized in that: The low-cost high-strength and toughness stainless steel for ophthalmic surgical knives has a yield strength of ≥930 MPa, a tensile strength of ≥1130 MPa, and an elongation of ≥28%.

8. The low-cost, high-strength and high-toughness stainless steel for ophthalmic surgical knives according to claim 6, characterized in that: The composition of the low-cost, high-strength and toughness stainless steel for ophthalmic surgical knives includes, by mass percentage, C≤0.18wt%, Si≤1.0wt%, S≤0.03wt%, P≤0.02wt%, Mn 2.0-3.0wt%, Cr 17.0-18.0wt%, Ni 7.0-8.0wt%, Cu 1.0-1.5wt%, and the rest is Fe and unavoidable impurities.

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