High-strength and high-toughness stainless steel wire material for ophthalmologic scalpel and preparation method of stainless steel wire material

Abstract

The invention belongs to the technical field of stainless steel, and particularly relates to a high-strength and high-toughness stainless steel wire for an ophthalmic scalpel and a preparation method of the high-strength and high-toughness stainless steel wire, the content of a precious element Ni is reduced, the content of a Cu element and the content of a Ca element are increased, and the high-strength and high-toughness stainless steel wire for the ophthalmic scalpel is obtained through the production process of hot rolling, solid solution, cold rolling, annealing, cold drawing, annealing, cold drawing and low-temperature liquid nitrogen treatment. The stainless steel wire with the separated nanoscale copper-rich phase and the fibrous microstructure is produced, the yield strength of the finally produced stainless steel wire is larger than or equal to 1130 MPa, the tensile strength is larger than or equal to 1550 MPa, the ductility is larger than or equal to 35%, and the requirement for machining and application of ophthalmic surgical tools can be met.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel, in particular to a high-strength and toughness stainless steel wire for an ophthalmic scalpel 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] Austenitic stainless steel, such as 304 stainless steel, which is cheaper than martensitic stainless steel, has high toughness and plasticity, but low strength. It cannot be strengthened by phase transformation and can only be strengthened by cold working. 304 austenitic stainless steel has a strong tendency to work hardening and excellent corrosion resistance. It can be used to make high-strength stainless steel wire. However, after the stainless steel wire is subjected to large deformation by drawing, the high-density grain boundaries, dislocations and other defects produced by the severe plastic deformation seriously limit the subsequent plastic deformation ability. Shear fracture will occur quickly after the material yields, and the toughness is insufficient. In addition, there are more Cr elements in 304 austenitic stainless steel, and the cutting stickiness is strong. When the ophthalmic scalpel is sharpened, built-up edge is generated, which makes processing difficult and affects the performance of the ophthalmic scalpel. Therefore, it is of great practical value to develop a high-strength and toughness stainless steel wire for ophthalmic scalpels and its preparation method. 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 high-strength and toughness stainless steel wire for ophthalmic scalpels 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 a stainless steel wire material for an ophthalmic surgical knife with high strength and toughness comprises the following steps:

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

[0008] S2. After the ingot is kept at 1230-1250℃ for 2-3h, it is immediately hot-rolled in multiple passes to obtain a bar;

[0009] S3, the bar 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 solution treated bar is subjected to multiple cold rolling to obtain a cold rolled bar;

[0011] S5, annealing the cold-rolled bar, and then air-cooling it to room temperature; the annealing temperature is 700-750°C, and the annealing time is 10-100 minutes;

[0012] S6, the annealed bar is subjected to multiple drawing passes to obtain a cold drawn wire;

[0013] S7, annealing the cold drawn wire, and then air cooling to room temperature; the annealing temperature is 200-250°C, and the annealing time is 100-180 minutes;

[0014] S8, the wire material after annealing is further drawn for multiple passes to obtain a cold drawn wire material;

[0015] S9. The cold-drawn wire is subjected to ultra-low temperature liquid nitrogen treatment, with the treatment temperature being ≤-100°C and the treatment time being ≥12h, to obtain a stainless steel wire with high strength and toughness for ophthalmic surgical knives.

[0016] As a preferred embodiment of the method for preparing a high-strength and toughness stainless steel wire for an ophthalmic scalpel described in the present invention, 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.

[0017] As a preferred embodiment of the method for preparing a high-strength and toughness stainless steel wire for ophthalmic surgical knives described in the present invention, wherein: in the step S2, the starting rolling temperature is ≥1150°C, and the final rolling temperature is ≥950°C.

[0018] As a preferred embodiment of the method for preparing a high-strength and toughness stainless steel wire for ophthalmic surgical knives described in the present invention, wherein: in the step S2, the deformation amount of a single hot rolling is less than 30%, and the total deformation amount is more than 50%, preferably, the total deformation amount is 50-60%.

[0019] As a preferred embodiment of the method for preparing a high-strength and toughness stainless steel wire for ophthalmic surgical knives described in the present invention, wherein: in the step S4, the single-pass cold rolling deformation is less than 20%, and the total deformation is above 50%, preferably, the total deformation is 50-60%.

[0020] As a preferred embodiment of the method for preparing a high-strength and toughness stainless steel wire for ophthalmic surgical knives described in the present invention, wherein: in the step S6, the single-pass cold drawing deformation is less than 15%, and the total deformation is above 60%, preferably, the total deformation is 60-70%.

[0021] As a preferred embodiment of the method for preparing a high-strength and toughness stainless steel wire for ophthalmic surgical knives described in the present invention, wherein: in the step S8, the single-pass cold drawing deformation is less than 15%, and the total deformation is above 70%, preferably, the total deformation is 70-80%.

[0022] To solve the above technical problem, according to another aspect of the present invention, the present invention provides the following technical solution:

[0023] A high-strength and toughness stainless steel wire for ophthalmic scalpels is prepared by adopting the above-mentioned method for preparing the high-strength and toughness stainless steel wire for ophthalmic scalpels.

[0024] As a preferred embodiment of the high-strength and toughness stainless steel wire for ophthalmic scalpels described in the present invention, the yield strength of the high-strength and toughness stainless steel wire for ophthalmic scalpels is ≥1130MPa, the tensile strength is ≥1550MPa, and the elongation is ≥35%.

[0025] As a preferred embodiment of the high-strength and toughness stainless steel wire for ophthalmic scalpels described in the present invention, the composition of the high-strength and toughness stainless steel wire for ophthalmic scalpels, in terms of mass percentage, includes: 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%, Ca 0.5-1.0wt%, and the rest is Fe and unavoidable impurities.

[0026] The beneficial effects of the present invention are as follows:

[0027] The invention provides a high-strength and toughness stainless steel wire 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 and the element Ca is increased. The stainless steel wire having a precipitated nano-scale copper-rich phase and a fibrous microstructure is produced by adopting a production process of hot rolling, solid solution, cold rolling, annealing, cold drawing, annealing, cold drawing and low-temperature liquid nitrogen treatment. The yield strength of the stainless steel wire produced finally is ≥1130MPa, the tensile strength is ≥1550MPa, and the elongation is ≥35%, which can meet the processing application of ophthalmic surgical knives. DETAILED DESCRIPTION

[0028] 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.

[0029] According to one aspect of the present invention, the present invention provides the following technical solution:

[0030] A method for preparing a stainless steel wire material for an ophthalmic surgical knife with high strength and toughness comprises the following steps:

[0031] S1. Smelting to obtain a stainless steel ingot; the stainless steel has a Cu content of 1.0-1.5wt%, a Ca content of ≤1.0wt%, and a Ni content of 7.0-8.0wt%;

[0032] S2. After the ingot is kept at 1230-1250℃ for 2-3h, it is immediately hot-rolled in multiple passes to obtain a bar;

[0033] S3, the bar 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;

[0034] S4, the solution treated bar is subjected to multiple cold rolling to obtain a cold rolled bar;

[0035] S5, annealing the cold-rolled bar, and then air-cooling it to room temperature; the annealing temperature is 700-750°C, and the annealing time is 10-100 minutes;

[0036] S6, the annealed bar is subjected to multiple drawing passes to obtain a cold drawn wire;

[0037] S7, annealing the cold drawn wire, and then air cooling to room temperature; the annealing temperature is 200-250°C, and the annealing time is 100-180 minutes;

[0038] S8, the wire material after annealing is further drawn for multiple passes to obtain a cold drawn wire material;

[0039] S9. The cold-drawn wire is subjected to ultra-low temperature liquid nitrogen treatment, with the treatment temperature being ≤-100°C and the treatment time being ≥12h, to obtain a stainless steel wire with high strength and toughness for ophthalmic surgical knives.

[0040] The invention reduces the content of Ni, a precious element, in stainless steel, increases the content of Cu and Ca elements, and produces stainless steel wire with a precipitated nano-scale copper-rich phase and a fibrous microstructure by adopting a production process of hot rolling, solid solution, cold rolling, annealing, cold drawing, annealing, cold drawing and low-temperature liquid nitrogen treatment.

[0041] 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.

[0042] Preferably, in step S2, the starting rolling temperature is ≥1150°C, and the finishing rolling temperature is ≥950°C.

[0043] Preferably, in step S2, the deformation amount of a single hot rolling pass is less than 30%, and the total deformation amount is more than 50%. Preferably, the total deformation amount is 50-60%.

[0044] Preferably, in step S4, the deformation amount of a single cold rolling pass is less than 20%, and the total deformation amount is more than 50%. Preferably, the total deformation amount is 50-60%.

[0045] Preferably, in step S6, the deformation of a single cold drawing pass is less than 15%, and the total deformation is above 60%. Preferably, the total deformation is 60-70%.

[0046] Preferably, in step S8, the deformation of a single cold drawing pass is less than 15%, and the total deformation is above 70%. Preferably, the total deformation is 70-80%.

[0047] According to another aspect of the present invention, the present invention provides the following technical solution:

[0048] A high-strength and toughness stainless steel wire for ophthalmic scalpels is prepared by adopting the above-mentioned method for preparing the high-strength and toughness stainless steel wire for ophthalmic scalpels.

[0049] Preferably, the high-strength and toughness stainless steel wire for ophthalmic surgical knives has a yield strength of ≥1130 MPa, a tensile strength of ≥1550 MPa, and an elongation of ≥35%.

[0050] Preferably, the composition of the high-strength and toughness stainless steel wire for ophthalmic scalpels, 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%, Ca0.5-1.0wt%, and the rest is Fe and unavoidable impurities.

[0051] 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.

[0052] Cr: Cr is used to increase the corrosion resistance and improve the oxidation resistance of stainless steel.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Ca: It is used to improve the strength of the material and increase the machinability of the material. However, excessive Ca will bring about harmful inclusions, reduce strength and toughness, and increase production costs. Therefore, considering all factors, the Ca content should be controlled at 0.5-1.0wt%.

[0057] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0058] The chemical compositions of the stainless steels of the embodiments of the present invention and the comparative examples are shown in Table 1.

[0059] Table 1 Chemical composition of stainless steel in various embodiments and comparative examples (wt%)

[0060]

[0061] 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.

[0062] Table 2 Production process parameters of stainless steel in various embodiments and comparative examples

[0063]

[0064] According to GB / T228.1-2021 "Metallic Materials Tensile Test Part 1: Room Temperature Test Method", standard tensile 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.

[0065] Table 3 Properties of stainless steel in various embodiments and comparative examples

[0066] Yield strength / MPa Tensile strength / MPa Elongation / % Example 1 1132 1560 38 Example 2 1147 1590 39 Example 3 1135 1573 41 Comparative Example 1 920 1112 22 Comparative Example 2 942 1148 31 Comparative Example 3 902 1013 18 Comparative Example 4 918 1106 21 Comparative Example 5 986 1264 27

[0067] The present invention reduces the content of precious element Ni and increases the content of Cu and Ca elements. By adopting the production process of hot rolling, solid solution, cold rolling, annealing, cold drawing, annealing, cold drawing and low-temperature liquid nitrogen treatment, a stainless steel wire with a precipitated nano-scale copper-rich phase and a fibrous microstructure is produced. The yield strength of the finally produced stainless steel wire is ≥1130MPa, the tensile strength is ≥1550MPa, and the elongation is ≥35%, which can meet the processing application of ophthalmic surgical tools.

[0068] 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 a high-strength and high-toughness stainless steel wire for ophthalmic surgical knives, characterized in that: The steps include: S1. Smelting to obtain a stainless steel ingot; the stainless steel has a Cu content of 1.0-1.5wt%, a Ca content of ≤1.0wt%, and a Ni content of 7.0-8.0wt%; S2. After the ingot is kept at 1230-1250℃ for 2-3h, it is immediately hot-rolled in multiple passes to obtain a bar; S3, the bar 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 solution treated bar is subjected to multiple cold rolling to obtain a cold rolled bar; S5, annealing the cold-rolled bar, and then air-cooling it to room temperature; the annealing temperature is 700-750°C, and the annealing time is 10-100 minutes; S6, the annealed bar is subjected to multiple drawing passes to obtain a cold drawn wire; S7, annealing the cold drawn wire, and then air cooling to room temperature; the annealing temperature is 200-250°C, and the annealing time is 100-180 minutes; S8, the wire material after annealing is further drawn for multiple passes to obtain a cold drawn wire material; S9. The cold-drawn wire is subjected to ultra-low temperature liquid nitrogen treatment, with the treatment temperature being ≤-100°C and the treatment time being ≥12h, to obtain a stainless steel wire with high strength and toughness for ophthalmic surgical knives.

2. The method for preparing the high-strength and toughness stainless steel wire for ophthalmic surgical knives according to claim 1, characterized in that: In the step S2, the starting rolling temperature is ≥1150°C, and the finishing rolling temperature is ≥950°C.

3. The method for preparing the high-strength and toughness stainless steel wire for ophthalmic surgical knives according to claim 1, characterized in that: In the step S2, the deformation amount of a single hot rolling pass is less than 30%, and the total deformation amount is more than 50%.

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

5. The method for preparing the high-strength and toughness stainless steel wire for ophthalmic surgical knives according to claim 1, characterized in that: In the step S6, the deformation of a single cold drawing pass is less than 15%, and the total deformation is more than 60%.

6. The method for preparing the high-strength and toughness stainless steel wire for ophthalmic surgical knives according to claim 1, characterized in that: In the step S8, the deformation of a single cold drawing pass is less than 15%, and the total deformation is more than 70%.

7. A high-strength and high-toughness stainless steel wire for ophthalmic surgical knives, characterized in that: The stainless steel wire with high strength and toughness for ophthalmic surgical knife is prepared by the preparation method of any one of claims 1 to 6.

8. The high-strength and toughness stainless steel wire for ophthalmic surgical knives according to claim 7, characterized in that: The high-strength and toughness stainless steel wire for ophthalmic surgical knives has a yield strength of ≥1130 MPa, a tensile strength of ≥1550 MPa, and an elongation of ≥35%.

9. The high-strength and toughness stainless steel wire for ophthalmic surgical knives according to claim 7, characterized in that: The composition of the high-strength and toughness stainless steel wire 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%, Cr17.0-18.0wt%, Ni 7.0-8.0wt%, Cu1.0-1.5wt%, Ca 0.5-1.0wt%, and the rest is Fe and unavoidable impurities.

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