2.6gpa-2.9gpa maraging steel wire rod and method of making

Abstract

This invention discloses a 2.6GPa-2.9GPa martensitic aging steel wire and its preparation method, belonging to the field of steel material manufacturing technology. The composition of the martensitic aging steel wire, by weight percentage, is: Co 14.0-17.0%, Ni 17.5-18.5%, Mo 6.0-8.0%, Ti 1.0-1.5%, Al 0.05-0.10%, W 0-1.0%, C≤0.005%, with the balance being Fe and unavoidable impurities. The tensile strength of the aging-treated wire is 2.6-2.9GPa, and the elongation A≥5%. The preparation method of this invention includes multi-pass small-deformation drawing and gradient intermediate heat treatment. This invention reconciles the contradiction between work hardening and recrystallization softening during cold working of high-alloy martensitic aging steel, thereby achieving ultra-high strength while controlling grain size and avoiding crack formation.

Description

Technical Field

[0001] This invention relates to the field of steel material manufacturing technology, and in particular to a 2.6GPa-2.9GPa martensitic aging steel wire and its preparation method. Background Technology

[0002] Martensitic aging steel wire possesses both ultra-high strength and high ductility, making it widely used in precision equipment components and high-end 3C communication fields. The main specifications are Φ1.0-2.0mm wire, with lengths of 2-2.5m, dimensional accuracy of -0.02mm, ellipticity ≤0.01mm, and straightness: 0.5mm / 2.0m or 0.5mm / 2.5m. Currently, domestic and international research has focused on designing tensile strength R... m A new type of martensitic aging steel with a strength of ≥2.6 GPa. The new composition system contains extremely high levels of strengthening elements such as Co, Mo, and Ti. Its cold working performance is lower than that of traditional 18Ni series martensitic aging steel. Therefore, its preparation process (especially drawing and heat treatment processes) needs to be developed and designed based on the new internal microstructure and property relationship in order to meet the requirements of higher strength and certain plasticity of martensitic aging steel wire in the cutting-edge 3C field.

[0003] Existing wire preparation methods involve pickling the wire rod before drawing to remove surface oxide scale. However, due to the low corrosion resistance of this martensitic aging steel, pickling damages the near-surface microstructure of the wire rod. Furthermore, the ellipticity and surface finish of the pickled wire rod do not meet the ultra-high surface quality requirements of advanced 3C and precision equipment components. The alloy wire described in this invention has a yield strength of 2100 MPa and a plasticity (elongation after fracture) of approximately 10.0% after aging treatment, which is insufficient to meet the tensile strength R... m ≥2.6GPa, yield strength R p0.2 Requirements for the preparation of novel martensitic aging steel wire with a pressure of ≥2.5 GPa.

[0004] In summary, existing technologies cannot simultaneously achieve ultra-high strength (R... m Under the premise of 2.6-2.9 GPa and good plasticity (elongation after fracture ≥5%), the wire material can simultaneously achieve extremely high dimensional accuracy, excellent straightness and bright and defect-free surface condition.

[0005] Therefore, existing technologies still need improvement. Summary of the Invention

[0006] Based on this, and addressing the shortcomings of the existing technology, this paper provides a 2.6GPa-2.9GPa martensitic aging steel wire and its preparation method, aiming to solve the problem of not being able to simultaneously achieve ultra-high strength (R... mUnder the premise of 2.6-2.9 GPa and good plasticity (elongation after fracture ≥5%), it simultaneously achieves the shortcomings of extremely high dimensional accuracy, excellent straightness and bright and defect-free surface of the filament.

[0007] To achieve the above objectives, the following technical solution is adopted: This invention provides a 2.6GPa-2.9GPa martensitic aging steel wire, wherein the composition of the martensitic aging steel wire, by weight percentage, is: Co 14.0-17.0%, Ni 17.5-18.5%, Mo 6.0-8.0%, Ti 1.0-1.5%, Al 0.05-0.10%, W 0-1.0%, C≤0.005%, with the balance being Fe and unavoidable impurities; The aging-treated wire has a diameter of 1.0-2.0 mm, a grain size of 3-6 µm, a tensile strength of 2.6-2.9 GPa, a yield strength of 2.5-2.8 GPa, and an elongation A ≥ 5%.

[0008] In some embodiments, the composition of the 2.6GPa-2.9GPa martensitic aging steel wire, by weight percentage, is: Co 15.0-16.0%, Ni 17.8-18.2%, Mo 6.5-7.5%, Ti 1.1-1.3%, Al 0.06-0.08%, W 0.1-0.8%, C≤0.003%, with the balance being Fe and unavoidable impurities.

[0009] The present invention also provides a method for preparing 2.6GPa-2.9GPa martensitic aging steel wire according to the above description, comprising: S101. Hot-rolled martensitic aging steel wire rods are solution treated and then surface-processed to obtain bright wire rods. S102. The bright-state coil is cold-drawn three times, and solution annealing is performed after each cold drawing to obtain the intermediate wire. S103. After another cold drawing of the intermediate wire, a solution-treated wire of the target diameter is obtained. S104. Perform solution heat treatment on the solution-treated filament of the target diameter and cool it to room temperature; S105. The wire material after solution heat treatment is subjected to surface processing and aging heat treatment to obtain martensitic aging steel wire material.

[0010] In some embodiments, in step S101, the surface processing is to remove the surface oxide layer to obtain a glossy disc; wherein the surface processing is a peeling and polishing process, and the diameter reduction is 0.3-0.5 mm.

[0011] In some embodiments, step S102 includes: S201. The bright-state coil is subjected to a first cold drawing to obtain a first intermediate wire; wherein the single-pass diameter reduction is 0.4-0.6 mm, the drawing rate is 3-5 m / min, and the coil is drawn to a diameter of 6.0-6.5 mm; the first intermediate wire is subjected to a first solution annealing treatment. S202. The wire after the first solution annealing treatment is subjected to a second cold drawing to obtain a second intermediate wire; wherein the single-pass diameter reduction is 0.3-0.5 mm, the drawing rate is 5-8 m / min, and the wire is drawn to a diameter of 4.0-4.5 mm; the second intermediate wire is subjected to a second solution annealing treatment. S203. The wire after the second solution annealing treatment is subjected to a third cold drawing to obtain a third intermediate wire; wherein the single-pass diameter reduction is 0.2-0.3 mm, the drawing rate is 5-8 m / min, and the wire is drawn to a diameter of 2.5-3.0 mm; the third intermediate wire is subjected to a third solution annealing treatment.

[0012] In some embodiments, in step S103, the single-pass diameter reduction of the intermediate filament after another cold drawing is 0.15-0.20 mm, the drawing rate is 5-8 m / min, and the filament is drawn to a diameter of 1.0-2.0 mm.

[0013] In some embodiments, step S101, the solution treatment of hot-rolled martensitic aging steel wire rod includes: solution treatment using a pit furnace, charging the material at a furnace temperature below 400°C, heating to 820°C at 10°C / minute, holding at that temperature for 2-5 hours, and then air-cooling the material to room temperature.

[0014] In some embodiments, the first and second solution annealing treatments include: solution annealing heat treatment using a vacuum double-chamber furnace, with the furnace temperature below 400°C, the furnace temperature increased to 820°C at 10°C / min, held for 45-60 minutes, and then the material is transferred to a cold chamber, filled with nitrogen and the cold chamber fan is turned on to bring the material temperature below 50°C before it is removed from the furnace; the third solution annealing treatment includes: intermediate solution annealing treatment using an online heat treatment furnace, with argon protection turned on, the furnace temperature at 820°C to start wire feeding, the holding time at 10-15 minutes, and natural air cooling after removal from the furnace.

[0015] In some embodiments, step S104, performing solution heat treatment on the solution-treated wire of the target diameter includes: performing solution annealing heat treatment on the coiled wire using a vacuum double-chamber furnace, charging the material at a furnace temperature below 400°C, raising the temperature to 820°C at 10°C / minute, holding the temperature for 30-40 minutes, then transferring the material into a cold chamber, filling it with nitrogen and turning on the cold chamber fan to bring the material temperature below 50°C before removing it from the furnace.

[0016] In some embodiments, step S105 includes aging heat treatment: using a vacuum furnace for aging at a temperature of 490-500°C for 3-8 hours, and after aging, filling the furnace with gas to cool it to below 50°C before removing it from the furnace.

[0017] The present invention has the following beneficial technical effects: The 2.6GPa-2.9GPa martensitic aging steel wire prepared by this invention achieves composite strengthening through high levels of Co, Mo, Ti, and other elements, while strictly limiting impurity elements such as C. Combined with the multi-pass small-deformation drawing and gradient intermediate heat treatment in the preparation method, the contradiction between work hardening and recrystallization softening during cold working of high-alloy martensitic aging steel is coordinated. Thus, while obtaining ultra-high strength, the grain size is controlled to avoid crack formation, and the final wire achieves precise dimensions and a bright surface.

[0018] This invention controls the grain size of martensitic aging steel wire to 3-6µm and increases its tensile strength R. m =2.6-2.9 GPa, yield strength R p0.2 =2.5-2.8GPa, elongation A≥5%; finished product specifications Φ1.0-2.0mm, length 2-2.5m, dimensional accuracy -0.02mm, ovality ≤0.01mm; straightness: 0.5mm / 2.0m or 0.5mm / 2.5m. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of the method for preparing 2.6GPa-2.9GPa martensitic aging steel wire according to the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0022] It should be understood that the embodiments of the invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the invention. Accordingly, all such modifications should be included within the scope of the invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the invention.

[0023] Based on the above objectives, a first aspect of the embodiments of the present invention provides a 2.6GPa-2.9GPa martensitic aging steel wire, wherein the composition of the martensitic aging steel wire, by weight percentage, is: Co 14.0-17.0%, Ni 17.5-18.5%, Mo 6.0-8.0%, Ti 1.0-1.5%, Al 0.05-0.10%, W 0-1.0%, C≤0.005%, with the balance being Fe and unavoidable impurities; The aging-treated wire has a diameter of 1.0-2.0 mm, a grain size of 3-6 µm, a tensile strength of 2.6-2.9 GPa, a yield strength of 2.5-2.8 GPa, and an elongation A ≥ 5%.

[0024] In a preferred embodiment of the present invention, the composition of the 2.6GPa-2.9GPa martensitic aging steel wire, by weight percentage, is: Co 15.0-16.0%, Ni 17.8-18.2%, Mo 6.5-7.5%, Ti 1.1-1.3%, Al 0.06-0.08%, W 0.1-0.8%, C≤0.003%, with the balance being Fe and unavoidable impurities.

[0025] This invention utilizes the cold work hardening law of 2.6-2.9 GPa martensitic aging steel and its austenite-martensitic transformation critical temperature. By gradient adjustment of the drawing diameter reduction of wire rod and wire and intermediate solution annealing treatment, 2.6-2.9 GPa martensitic aging steel wire products with Φ1.0-2.0 mm are drawn to control the grain size of the wire to 3-6 µm. The tensile strength R of the aged wire is [not specified]. m The strength is 2.6-2.9 GPa, elongation A≥5%; finished product specifications Φ1.0-2.0mm, length 2-2.5m, dimensional accuracy -0.02mm, ovality ≤0.01mm; straightness: 0.5mm / 2.0m or 0.5mm / 2.5m.

[0026] A second aspect of the present invention provides a method for preparing 2.6GPa-2.9GPa martensitic aging steel wire. Figure 1 The diagram shown is a schematic flowchart of the method.

[0027] like Figure 1 As shown, the preparation includes: S101. Hot-rolled martensitic aging steel wire rods are solution treated and then surface-processed to obtain bright wire rods. S102. The bright-state coil is cold-drawn three times, and solution annealing is performed after each cold drawing to obtain the intermediate wire. S103. After another cold drawing of the intermediate wire, a solution-treated wire of the target diameter is obtained. S104. Perform solution heat treatment on the solution-treated filament of the target diameter and cool it to room temperature; S105. The wire material after solution heat treatment is subjected to surface processing and aging heat treatment to obtain martensitic aging steel wire material.

[0028] Specifically, by combining multi-pass small-deformation drawing with gradient intermediate heat treatment, the contradiction between work hardening and recrystallization softening during cold working of high-alloy martensitic aging steel is coordinated. This allows for the control of grain size while obtaining ultra-high strength, avoiding crack formation, and achieving precise dimensions and a bright surface of the final wire.

[0029] Specifically, the main process for preparing hot-rolled martensitic aging steel coil billets used in this embodiment is as follows: steel ingots are smelted using a vacuum induction furnace and a vacuum arc furnace, forged into 120-150mm square billets, and then hot-rolled into Φ8-10mm coils.

[0030] In a preferred embodiment of the present invention, in step S101, the surface processing is to remove the surface oxide layer to obtain a bright disc; wherein, the surface processing is a peeling and polishing process, and the diameter reduction is 0.3-0.5 mm.

[0031] Specifically, surface treatment can mechanically and non-destructively remove the oxide layer and defects on the surface of the coil, avoiding near-surface structural damage and uneven surface quality caused by pickling. This provides a blank base with accurate dimensions, bright surface, and no defects for subsequent precision drawing, which is a prerequisite for obtaining wire with high dimensional accuracy and high surface quality.

[0032] In a preferred embodiment of the present invention, step S102 includes: S201. The bright-state coil is subjected to a first cold drawing to obtain the first intermediate wire; wherein the single-pass diameter reduction is 0.4-0.6 mm, the drawing rate is 3-5 m / min, and the coil is drawn to a diameter of 6.0-6.5 mm; the first intermediate wire is subjected to a first solution annealing treatment. S202. The wire after the first solution annealing treatment is subjected to a second cold drawing to obtain the second intermediate wire; wherein the single-pass diameter reduction is 0.3-0.5 mm, the drawing rate is 5-8 m / min, and the wire is drawn to a diameter of 4.0-4.5 mm; the second intermediate wire is subjected to a second solution annealing treatment. S203. The wire after the second solution annealing treatment is subjected to a third cold drawing to obtain the third intermediate wire; wherein the single-pass diameter reduction is 0.2-0.3 mm, the drawing rate is 5-8 m / min, and the wire is drawn to a diameter of 2.5-3.0 mm; the third intermediate wire is subjected to a third solution annealing treatment.

[0033] Specifically, by progressively reducing the diameter reduction per pass (from 0.4-0.6 mm to 0.3-0.5 mm to 0.2-0.3 mm) in stages and matching the corresponding drawing rate, a gradient and refined control of the processing deformation is achieved. This effectively distributes and releases accumulated processing stress. Combined with solution treatment after each drawing, it regulates the recrystallization behavior and microstructure evolution of the material, thereby maintaining good plasticity of the material during multiple cold working cycles, preventing drawing fracture, and creating conditions for finally obtaining a uniform and fine grain structure (3-6 µm).

[0034] In a preferred embodiment of the present invention, in step S103, the single-pass diameter reduction of the intermediate filament after another cold drawing is 0.15-0.20 mm, the drawing rate is 5-8 m / min, and the filament is drawn to a diameter of 1.0-2.0 mm.

[0035] Specifically, the final drawing is performed with minimal deformation at the stage close to the required size. This minimizes damage to the already formed microstructure, reduces the final processing stress, and ensures that the wire achieves the target diameter (Φ1.0-2.0mm).

[0036] In a preferred embodiment of the present invention, step S101, the solution treatment of hot-rolled martensitic aging steel wire rod includes: solution treatment using a pit furnace, charging the material at a furnace temperature below 400°C, heating to 820°C at 10°C / minute, holding at that temperature for 2-5 hours, and then air-cooling the material to room temperature.

[0037] Specifically, by controlling the heating rate and sufficient holding time, the alloying elements in the original hot-rolled coil are fully dissolved, resulting in a single-phase austenitic structure with uniform composition and high supersaturation, and eliminating hot working stress.

[0038] In a preferred embodiment of the present invention, the first solution annealing treatment and the second solution annealing treatment include: solution annealing heat treatment using a vacuum double-chamber furnace, with the furnace temperature below 400°C, the furnace temperature increased to 820°C at 10°C / min, held for 45-60 minutes, and then the material is transferred to a cold chamber, nitrogen is purged and the cold chamber fan is turned on to bring the material temperature below 50°C before it is taken out of the furnace; the third solution annealing treatment includes: intermediate solution annealing treatment using an online heat treatment furnace, with argon protection turned on, the furnace temperature at 820°C to start wire feeding, the holding time at 10-15 minutes, and natural air cooling after taking out of the furnace.

[0039] The first solution annealing process includes: solution annealing heat treatment in a vacuum double-chamber furnace, with the furnace temperature below 400℃ when the material is charged, the temperature is increased to 820℃ at a rate of 10℃ / minute, held for 60 minutes, then the material is transferred to a cold chamber, purged with nitrogen, and the cold chamber fan is turned on to maintain the material temperature below 50℃ before removing it from the furnace. The second solution annealing process includes: solution annealing heat treatment in a vacuum double-chamber furnace, with the furnace temperature below 400℃ when the material is charged, the temperature is increased to 820℃ at a rate of 10℃ / minute, held for 45 minutes, then the material is transferred to a cold chamber, purged with nitrogen, and the cold chamber fan is turned on to maintain the material temperature below 50℃ before removing it from the furnace.

[0040] Specifically, the first two treatments are carried out in a vacuum environment for a long time to eliminate the work hardening accumulated from the large deformation in the early stage, fully recrystallize, and restore plasticity; the third treatment is a rapid wire drawing process under a protective atmosphere with a short time, which aims to partially eliminate work hardening while avoiding excessive grain growth, so as to retain a certain work hardening basis for the final drawing.

[0041] In a preferred embodiment of the present invention, step S104, the solution heat treatment of the solution-treated filament of the target diameter, includes: performing solution annealing heat treatment on the coiled filament in a vacuum double-chamber furnace, charging the material at a furnace temperature below 400°C, heating to 820°C at a rate of 10°C / minute, holding at that temperature for 30-40 minutes, then transferring the material to a cold chamber, filling it with nitrogen and turning on the cold chamber fan to bring the material temperature below 50°C before removing it from the furnace. The microhardness of the solution-treated filament is 380-400 HV.

[0042] Specifically, after the filament reaches its final dimensions, a precise final solution treatment is performed. This aims to completely eliminate all cold working stress, obtain a fully recrystallized, uniformly fine-grained (3-6µm) supersaturated solid solution structure, and stabilize the microhardness of the filament within a suitable range of 380-400HV.

[0043] In a preferred embodiment of the present invention, the filament is subjected to aging treatment, and the tensile strength R of the filament is... m =2.6-2.9 GPa, yield strength R p0.2 =2.5-2.8GPa, elongation A≥5%.

[0044] In step S105, the aging heat treatment includes: using a vacuum furnace for heat treatment, with an aging temperature of 490-500℃ and an aging time of 3-8 hours. After the aging is completed, gas is introduced into the furnace to cool it to below 50℃ before it is taken out of the furnace.

[0045] Specifically, by holding the material at a specific temperature for an extended period, a large number of intermetallic compounds (such as Ni3Ti and Fe2Mo) nanoscale reinforcing phases are precipitated in an orderly and dispersed manner within the supersaturated solid solution, thereby achieving significant precipitation strengthening. This results in a final tensile strength of 2.6-2.9 GPa and a yield strength of 2.5-2.8 GPa for the wire. The vacuum environment and rapid gas-filled cooling prevent oxidation, ensuring the uniformity of the wire's surface quality and properties.

[0046] In a preferred embodiment of the present invention, step S105 includes surface processing including: straightening the solid solution coiled wire, cutting it to length, and centerless grinding, with a grinding reduction of 0.03-0.05 mm, removing defects such as the oxide layer on the surface of the wire, so that the wire reaches a bright state and the grain size is controlled at 3-6 µm.

[0047] The drawing and heat treatment method for maraging steel described in this invention is based on the equipment conditions of metal wire manufacturing plants, is easy to operate, and has high production efficiency. The maraging steel wire described in this invention can be widely applied to hinges, shafts, and precision equipment shafts in the 3C electronics field, with broad application prospects.

[0048] The present invention will be further illustrated by the following examples.

[0049] Table 1. Chemical composition of the examples and comparative examples (in weight percentage)

[0050] Table 2. Performance Comparison of Examples and Comparative Examples

[0051] Example 1 The composition of the 2.6GPa-2.9GPa martensitic aging steel wire in this embodiment is shown in Table 1, and the specific preparation steps are as follows: Step 1: Solution treatment of the disc The Φ8mm hot-rolled wire rod was solution treated in a pit furnace. The furnace temperature was 350℃ when the material was loaded, and the temperature was increased to 820℃ at a rate of 10℃ / minute. The temperature was held for 3 hours, and then the material was removed from the furnace and air-cooled to room temperature. Step 2: Surface processing The solid solution-treated discs were peeled and polished to obtain a Φ7.6mm glossy disc.

[0052] Step 3, First Cold Drawing The bright Φ7.6mm wire rods are cold-drawn according to the following specifications: Φ7.6mm-Φ7.1mm-Φ6.6mm-Φ6.2mm, with a drawing speed of 5m / min; Step 4: First intermediate vacuum annealing solution heat treatment Solution annealing heat treatment is carried out in a vacuum double-chamber furnace. The furnace temperature is 350℃ when the material is loaded, and the temperature is increased to 820℃ at 10℃ / minute. The temperature is held for 1 hour, and then the material is transferred to the cold chamber. Nitrogen gas is purged and the cold chamber fan is turned on to keep the material temperature below 50℃ before it is taken out of the furnace.

[0053] Step 5, Second cold drawing: The Φ6.2mm intermediate solution annealed wire coils are cold drawn according to the following specifications: Φ6.2mm-Φ5.8mm-Φ5.4mm-Φ5.0mm-Φ4.6mm-Φ4.2mm, with a drawing speed of 8m / min; Step 6: Second intermediate solution annealing heat treatment Solution annealing heat treatment is carried out in a vacuum double-chamber furnace. The furnace temperature is 350℃ when the material is loaded, and the temperature is increased to 820℃ at 10℃ / min. The temperature is held for 45 minutes, and then the material is transferred to the cold chamber. Nitrogen gas is purged and the cold chamber fan is turned on to keep the material temperature below 50℃ before it is taken out of the furnace. Step 7, Third Cold Drawing The Φ4.2mm intermediate solution annealed wire coils are cold drawn according to the following specifications: Φ4.2mm-Φ3.9mm-Φ3.6mm-Φ3.3mm-Φ3.0mm, with a drawing speed of 6m / min; Step 8: Third intermediate solution annealing heat treatment Intermediate solution annealing was performed using an online heat treatment furnace with argon protection activated. The wire feeding was started at a furnace temperature of 820℃ and held for 15 minutes. The wire was then naturally air-cooled after being removed from the furnace. Step 9, Fourth Cold Pulling The Φ3.0mm intermediate solution annealed wire coils are cold drawn according to the following specifications: Φ3.0mm-Φ2.8mm-Φ2.6mm-Φ2.4mm-Φ2.0mm, with a drawing speed of 6m / min; Step 10: Final Vacuum Solution Heat Treatment The coiled wire was subjected to solution annealing heat treatment using a vacuum double-chamber furnace. The furnace was loaded at 360°C and heated to 820°C at a rate of 10°C / minute. The temperature was held for 40 minutes, and then the material was transferred to the cold chamber. Nitrogen gas was introduced and the cold chamber fan was turned on to keep the material temperature below 50°C before it was removed from the furnace.

[0054] Step 11: Surface processing The Φ2.0mm solution-treated coiled wire is straightened, cut to length, and ground without centering until it reaches Φ1.95mm. Defects such as the oxide layer on the surface of the wire are removed, and the wire reaches a bright state.

[0055] Step 12: Time-sensitive processing The filament obtained in step 11 is subjected to aging treatment. The aging heat treatment process is as follows: a double-chamber vacuum furnace is used for heat treatment, the aging temperature is 500℃, the aging time is 5 hours, and after the aging is completed, gas is introduced into the furnace to cool it to below 50℃ before it is taken out of the furnace.

[0056] Example 2 The composition of the 2.6GPa-2.9GPa martensitic aging steel wire in this embodiment is shown in Table 1, and the specific preparation steps are as follows: Step 1: Solution treatment of the disc Φ10mm hot-rolled wire rods were solution treated in a pit furnace. The furnace temperature was 350℃ when the material was loaded, and the temperature was increased to 820℃ at a rate of 10℃ / minute. The temperature was held for 5 hours, and then the material was removed from the furnace and air-cooled to room temperature. Step 2: Surface processing The solid solution-treated discs were peeled and polished to obtain a Φ9.5mm glossy disc.

[0057] Step 3, First Cold Drawing The bright Φ9.5mm wire rods are cold-drawn according to the following specifications: Φ9.5mm-Φ9.0mm-Φ8.4mm-Φ7.9mm-Φ7.4mm-Φ7.0mm-Φ6.6mm-Φ6.0mm, with a drawing speed of 5m / min; Step 4: First intermediate vacuum annealing solution heat treatment Solution annealing heat treatment is carried out in a vacuum double-chamber furnace. The furnace temperature is 350℃ when the material is loaded, and the temperature is increased to 820℃ at 10℃ / minute. The temperature is held for 1 hour, and then the material is transferred to the cold chamber. Nitrogen gas is purged and the cold chamber fan is turned on to keep the material temperature below 50℃ before it is taken out of the furnace.

[0058] Step 5, Second cold drawing: The Φ6.0mm intermediate solution annealed wire coils are cold drawn according to the following specifications: Φ6.0mm-Φ5.5mm-Φ5.0mm-Φ4.6mm-Φ4.3mm-Φ4.0mm, with a drawing speed of 8m / min; Step 6: Second intermediate solution annealing heat treatment Solution annealing heat treatment is carried out in a vacuum double-chamber furnace. The furnace temperature is 350℃ when the material is loaded, and the temperature is increased to 820℃ at 10℃ / min. The temperature is held for 45 minutes, and then the material is transferred to the cold chamber. Nitrogen gas is purged and the cold chamber fan is turned on to keep the material temperature below 50℃ before it is taken out of the furnace. Step 7, Third Cold Drawing The Φ4.0mm intermediate solution annealed wire coils are cold drawn according to the following specifications: Φ4.0mm-Φ3.7mm-Φ3.6mm-Φ3.3mm-Φ3.0mm-Φ2.7mm-Φ2.5mm, with a drawing speed of 6m / min; Step 8: Third intermediate solution annealing heat treatment Intermediate solution annealing was performed in an online heat treatment furnace with argon protection activated. The wire feeding was started at a furnace temperature of 820℃ and held for 10 minutes. After being taken out of the furnace, the wire was naturally air-cooled. Step 9, Fourth Cold Pulling The Φ2.5mm intermediate solution annealed wire coils are cold drawn according to the following specifications: Φ2.5mm-Φ2.3mm-Φ2.1mm-Φ1.9mm-Φ1.7mm-Φ1.5mm-Φ1.3mm-Φ1.15mm-Φ1.05mm, with a drawing speed of 5m / min; Step 10: Final Vacuum Solution Heat Treatment The coiled wire was subjected to solution annealing heat treatment using a vacuum double-chamber furnace. The furnace was loaded at 360°C and heated to 820°C at a rate of 10°C / minute. The temperature was held for 30 minutes, and then the material was transferred to the cold chamber. Nitrogen gas was introduced and the cold chamber fan was turned on to keep the material temperature below 50°C before it was removed from the furnace.

[0059] Step 11: Surface processing The Φ1.05mm solution-treated coiled wire is straightened, cut to length, and ground without centering until it reaches Φ1.00mm. Defects such as the oxide layer on the surface of the wire are removed, and the wire reaches a bright state.

[0060] Step 12: Time-sensitive processing The filament obtained in step 11 is subjected to aging treatment. The aging heat treatment process is as follows: a double-chamber vacuum furnace is used for heat treatment, the aging temperature is 500℃, the aging time is 4 hours, and after the aging is completed, gas is introduced into the furnace to cool it to below 50℃ before it is taken out of the furnace.

[0061] Example 3 The composition of the 2.6GPa-2.9GPa martensitic aging steel wire in this embodiment is shown in Table 1, and the specific preparation steps are as follows: Step 1: Solution treatment of the disc The Φ9mm hot-rolled wire rod was solution treated in a pit furnace. The furnace temperature was 350℃ when the material was loaded, and the temperature was increased to 820℃ at a rate of 10℃ / minute. The temperature was held for 5 hours, and then the material was removed from the furnace and air-cooled to room temperature. Step 2: Surface processing The solid solution-treated discs were peeled and polished to obtain a bright disc with a diameter of 8.6 mm.

[0062] Step 3, First Cold Drawing The bright Φ8.6mm wire rods are cold-drawn according to the following specifications: Φ8.6mm-Φ8.1mm-Φ7.6mm-Φ7.1mm-Φ6.8mm-Φ6.5mm, with a drawing speed of 5m / min; Step 4: First intermediate vacuum annealing solution heat treatment Solution annealing heat treatment is carried out in a vacuum double-chamber furnace. The furnace temperature is 350℃ when the material is loaded, and the temperature is increased to 820℃ at 10℃ / minute. The temperature is held for 1 hour, and then the material is transferred to the cold chamber. Nitrogen gas is purged and the cold chamber fan is turned on to keep the material temperature below 50℃ before it is taken out of the furnace.

[0063] Step 5, Second cold drawing: The Φ6.5mm intermediate solution annealed wire coils are cold drawn according to the following specifications: Φ6.5mm-Φ6.0mm-Φ5.5mm-Φ5.0mm-Φ4.5mm, with a drawing speed of 6m / min; Step 6: Second intermediate solution annealing heat treatment Solution annealing heat treatment is carried out in a vacuum double-chamber furnace. The furnace temperature is 350℃ when the material is loaded, and the temperature is increased to 820℃ at 10℃ / min. The temperature is held for 45 minutes, and then the material is transferred to the cold chamber. Nitrogen gas is purged and the cold chamber fan is turned on to keep the material temperature below 50℃ before it is taken out of the furnace. Step 7, Third Cold Drawing The Φ4.0mm intermediate solution annealed wire coils are cold drawn according to the following specifications: Φ4.5mm-Φ4.0mm-Φ3.6mm-Φ3.2mm-Φ2.8mm, with a drawing speed of 6m / min; Step 8: Third intermediate solution annealing heat treatment Intermediate solution annealing was performed in an online heat treatment furnace with argon protection activated. The wire feeding was started at a furnace temperature of 820℃ and held for 12 minutes. The wire was then naturally air-cooled after being removed from the furnace. Step 9, Fourth Cold Pulling The Φ2.8mm intermediate solution annealed wire is cold drawn according to the following specifications: Φ2.8mm-Φ2.6mm-Φ2.4mm-Φ2.2mm-Φ2.0mm-Φ1.8mm-Φ1.6mm-Φ1.45mm, with a drawing speed of 5m / min; Step 10: Final Vacuum Solution Heat Treatment The coiled wire was subjected to solution annealing heat treatment using a vacuum double-chamber furnace. The furnace was loaded at 360°C and heated to 820°C at a rate of 10°C / minute. The temperature was held for 30 minutes, and then the material was transferred to the cold chamber. Nitrogen gas was introduced and the cold chamber fan was turned on to keep the material temperature below 50°C before it was removed from the furnace.

[0064] Step 11: Surface processing The Φ1.45mm solution-treated coiled wire is straightened, cut to length, and ground without centering until it reaches Φ1.40mm. Defects such as the oxide layer on the surface of the wire are removed, and the wire reaches a bright state.

[0065] Step 12: Time-sensitive processing The filament obtained in step 11 is subjected to aging treatment. The aging heat treatment process is as follows: a double-chamber vacuum furnace is used for heat treatment, the aging temperature is 500℃, the aging time is 4 hours, and after the aging is completed, gas is introduced into the furnace to cool it to below 50℃ before it is taken out of the furnace.

[0066] Comparative Example The steel wire composition for this comparative example is shown in Table 1, and the specific preparation steps are as follows: 1) Blank preparation: Same as step 1 in Example 2, to obtain Φ9.0mm hot-rolled coil.

[0067] 2) Solution treatment: Same as step 2 in Example 2.

[0068] 3) Surface treatment: Acid pickling was used instead of peeling and polishing. The solution-treated discs were immersed in a 15% hydrochloric acid solution and pickled at 50°C for 20 minutes to remove the oxide scale. They were then rinsed with water and dried. The diameter of the discs after pickling was measured to be approximately Φ8.8 mm, with slight corrosion pits on the surface.

[0069] 4) Drawing process: The three intermediate solution heat treatments (steps 4, 6, and 8) in Example 2 are omitted, and continuous large deformation drawing is adopted: First drawing: The wire is drawn directly from Φ8.8mm to Φ4.5mm, with a large reduction in diameter per pass. Lubrication and cooling are used during the process. The wire temperature rises significantly after drawing.

[0070] Second drawing: Without heat treatment, the Φ4.5mm wire is directly drawn to the target diameter Φ1.5mm.

[0071] 5) Final solution treatment: Same as step 10 in Example 2, perform solution treatment on the Φ1.5mm wire.

[0072] 6) Surface finishing: Same as step 11 in Example 2, perform straightening, cutting and grinding.

[0073] 7) Aging treatment: Same as step 13 in Example 2, aging at 495℃ for 5 hours.

[0074] By comparing Examples 1-3 with the Comparative Examples (refer to Table 2 for performance data): The comparative example uses simplified continuous drawing with large deformation. Due to the lack of intermediate solution treatment to eliminate work hardening and restore material plasticity, severe work hardening occurs in the later stages of drawing, leading to exhaustion of material plasticity and a high risk of fracture. The yield is extremely low (<30%), making industrial production impractical. In contrast, Examples 1-3 of this invention effectively manage the work hardening process through gradient diameter reduction combined with multiple intermediate solution treatments, ensuring good plasticity throughout and achieving a high yield. The comparative example uses acid pickling, which damages the disc surface, and the large deformation drawing results in significant dimensional fluctuations. Examples 1-3 use mechanical peeling and polishing, providing a smooth billet surface, which, combined with precision drawing with small deformation, achieves high dimensional accuracy. The comparative example, due to insufficient intermediate recrystallization, has an uneven final microstructure with coarse grains and processing texture, resulting in low strength (especially R). m The strength and plasticity of the samples were lower than those of Examples 1-3, and they could not meet the comprehensive requirements of high strength and high plasticity. Examples 1-3 achieved a good match between strength and plasticity by obtaining uniform and fine grains through optimized processes.

[0075] The 2.6-2.9 GPa martensitic aging steel wire and its preparation method provided by this invention can achieve a microstructure with a grain size controlled at 3-6 µm and a tensile strength R m =2.6-2.9 GPa, yield strength R p0.2 =2.5-2.8GPa, elongation A≥5% martensitic aging steel wire; moreover, the finished wire meets the stringent requirements of the cutting-edge 3C field and the precision equipment parts field for wire size, surface quality, etc.

[0076] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. Although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0077] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A martensitic aging steel wire with a lifespan of 2.6 GPa-2.9 GPa, characterized in that, The composition of the martensitic aging steel wire, by weight percentage, is: Co 14.0-17.0%, Ni 17.5-18.5%, Mo 6.0-8.0%, Ti 1.0-1.5%, Al 0.05-0.10%, W 0-1.0%, C≤0.005%, with the balance being Fe and unavoidable impurities; The aging-treated wire has a diameter of 1.0-2.0 mm, a grain size of 3-6 µm, a tensile strength of 2.6-2.9 GPa, a yield strength of 2.5-2.8 GPa, and an elongation of ≥5%.

2. The 2.6GPa-2.9GPa martensitic aging steel wire according to claim 1, characterized in that, The composition of the martensitic aging steel wire, by weight percentage, is: Co 15.0-16.0%, Ni 17.8-18.2%, Mo 6.5-7.5%, Ti 1.1-1.3%, Al 0.06-0.08%, W 0.1-0.8%, C≤0.003%, with the balance being Fe and unavoidable impurities.

3. A method for preparing 2.6GPa-2.9GPa martensitic aging steel wire according to any one of claims 1-2, characterized in that, include: S101. Hot-rolled martensitic aging steel wire rods are solution treated and then surface-processed to obtain bright wire rods. S102. The bright-state coil is cold-drawn three times, and solution annealing is performed after each cold drawing to obtain the intermediate wire. S103. After another cold drawing of the intermediate wire, a solution-treated wire of the target diameter is obtained. S104. Perform solution heat treatment on the solution-treated filament of the target diameter and cool it to room temperature; S105. The wire material after solution heat treatment is subjected to surface processing and aging heat treatment to obtain martensitic aging steel wire material.

4. The preparation method according to claim 3, characterized in that, In step S101, the surface processing is to remove the surface oxide layer to obtain a bright disc; wherein, the surface processing is a peeling and polishing process, and the diameter reduction is 0.3-0.5 mm.

5. The preparation method according to claim 3, characterized in that, Step S102 includes: S201. The bright-state coil is subjected to a first cold drawing to obtain a first intermediate wire; wherein the single-pass diameter reduction is 0.4-0.6 mm, the drawing rate is 3-5 m / min, and the coil is drawn to a diameter of 6.0-6.5 mm; the first intermediate wire is subjected to a first solution annealing treatment. S202. The wire after the first solution annealing treatment is subjected to a second cold drawing to obtain a second intermediate wire; wherein the single-pass diameter reduction is 0.3-0.5 mm, the drawing rate is 5-8 m / min, and the wire is drawn to a diameter of 4.0-4.5 mm; the second intermediate wire is subjected to a second solution annealing treatment. S203. The wire after the second solution annealing treatment is subjected to a third cold drawing to obtain a third intermediate wire; wherein the single-pass diameter reduction is 0.2-0.3 mm, the drawing rate is 5-8 m / min, and the wire is drawn to a diameter of 2.5-3.0 mm; the third intermediate wire is subjected to a third solution annealing treatment.

6. The preparation method according to claim 3, characterized in that, In step S103, the single-pass diameter reduction of the intermediate wire after another cold drawing is 0.15-0.20 mm, the drawing rate is 5-8 m / min, and the wire is drawn to a diameter of 1.0-2.0 mm.

7. The preparation method according to claim 3, characterized in that, In step S101, the solution treatment of hot-rolled martensitic aging steel wire rod includes: solution treatment using a pit furnace, charging the material at a furnace temperature below 400°C, heating to 820°C at a rate of 10°C / minute, holding at that temperature for 2-5 hours, and then air-cooling the material to room temperature.

8. The preparation method according to claim 5, characterized in that, The first and second solution annealing processes include: solution annealing heat treatment using a vacuum double-chamber furnace, with the furnace temperature below 400℃ when the material is loaded, heated to 820℃ at a rate of 10℃ / minute, held for 45-60 minutes, and then the material is transferred to a cold chamber, filled with nitrogen and the cold chamber fan is turned on to keep the material temperature below 50℃ before it is removed from the furnace; the third solution annealing process includes: intermediate solution annealing using an online heat treatment furnace, with argon protection turned on, the furnace temperature at 820℃ when wire feeding begins, held for 10-15 minutes, and then naturally air-cooled after removal from the furnace.

9. The preparation method according to claim 3, characterized in that, In step S104, the solution heat treatment of the solution-treated wire of the target diameter includes: using a vacuum double-chamber furnace to perform solution annealing heat treatment on the coiled wire. The furnace temperature is below 400°C when the material is loaded, and the temperature is increased to 820°C at 10°C / minute. The temperature is held for 30-40 minutes, and then the material is transferred to the cold chamber. Nitrogen gas is filled and the cold chamber fan is turned on to make the material temperature below 50°C before it is taken out of the furnace.

10. The preparation method according to claim 3, characterized in that, In step S105, the aging heat treatment includes: using a vacuum furnace for heat treatment, with an aging temperature of 490-500℃ and an aging time of 3-8 hours. After the aging is completed, gas is introduced into the furnace to cool it to below 50℃ before it is taken out of the furnace.

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