A maraging steel wire material of 2.3 gpa or more and a method of manufacturing the same

Abstract

This invention relates to the field of martensitic aging steel production technology, specifically disclosing a martensitic aging steel wire with a pressure of 2.3 GPa or higher and its preparation method. The preparation method includes: forming a steel ingot into a coil with a diameter of 8-10 mm; subjecting the coil to solution treatment, cooling it to room temperature, and then performing surface processing to obtain a first intermediate wire; subjecting the first intermediate wire to multiple drawing cycles to obtain a wire with a diameter of 1-2 mm; wherein the drawing cycle treatment includes: cold drawing followed by online solution heat treatment. This invention produces martensitic aging steel wire products with a diameter of Φ1.0~2.0mm and a Pa value of 2.3GPa or higher by gradient adjustment of the drawing diameter reduction of wire rod and wire and intermediate solution annealing treatment, thereby controlling the grain size of the wire to 3~6µm. The yield strength Rp0.2>2.3GPa, tensile strength Rm>2.4GPa, and elongation A≥5% of the wire after aging treatment are achieved. Furthermore, the preparation method is designed based on the equipment conditions of metal wire manufacturing manufacturers, making it easy to operate, highly efficient, and with high product quality stability.

Description

Technical Field

[0001] This invention relates to the field of martensitic aging steel production technology, and in particular to a martensitic aging steel wire with a pressure of 2.3 GPa or higher and its preparation method. Background Technology

[0002] Martensitic aging steel possesses ultra-high strength and high plasticity, along with excellent machinability, and has long been used in major national strategic fields such as aerospace, nuclear energy, and marine engineering. Currently, the highest strength grade of commercially available martensitic aging steel has a yield strength Rp0.2 > 2.3 GPa. Previously, load-bearing structural components such as hinges and pivots in 3C products and pivots in precision equipment mainly used martensitic aging steel or titanium alloy wire with a strength below 2.0 GPa. In recent years, with the development of mid-to-high-end mobile phones in my country, higher requirements have been placed on product lightweighting, making martensitic aging steel wire with a strength above 2.3 GPa the preferred core structural material in mid-to-high-end mobile phones and consumer electronics. Unlike the large bars and profiles used in major national strategic fields such as aerospace, nuclear energy, and marine engineering, the 3C communications and precision equipment fields require new martensitic aging steels in the form of wires with diameters of Φ1.0~2.0mm. However, due to the high strength of martensitic aging steels with a strength of 2.3GPa and above, the wire preparation process needs to be developed and designed based on the evolution of its internal structure and properties during the wire preparation process.

[0003] Existing high-strength martensitic aging steel wires, with a diameter of approximately 2.2-2.6 mm, achieve a maximum tensile strength of 2230 MPa at room temperature. When the diameter is around 1-2 mm, the tensile strength is approximately 2038 MPa-2132 MPa. However, this strength still cannot meet the strength requirements (tensile strength above 2300 MPa) for key load-bearing structural components in the high-end 3C industry.

[0004] Therefore, existing technologies still need improvement. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a martensitic aging steel wire with a strength of 2.3 GPa or higher and a method for its preparation.

[0006] To address the aforementioned technical problems, some embodiments of the present invention disclose a method for preparing martensitic aging steel wire with a pressure of 2.3 GPa or higher, comprising: Step 1: Shape the steel ingot into a disc with a diameter of 8-10mm; Step 2: The coil is solution treated, cooled to room temperature, and then surface processed to obtain the first intermediate filament. Step 3: Perform multiple drawing cycles on the first intermediate wire to obtain a wire with a diameter of 1-2 mm; The drawing cycle process includes: online solution heat treatment after cold drawing; Furthermore, in step three, during the drawing cycle treatment, the drawing amount in the later cycle is less than that in the previous cycle, and the online solution treatment temperature is 815-825℃.

[0007] Further, by mass percentage, the composition of the steel ingot includes: Co 11.50-12.50%, Ni 18.00-19.00%, Mo 4.60-5.20%, Ti 1.30-1.60%, Al 0.05-0.15%, with the balance being Fe and unavoidable impurities.

[0008] Furthermore, in step two, the solution treatment temperature is 820-830℃, the holding time is 1.5-3 hours, and then it is air-cooled to room temperature; the surface processing includes peeling and polishing, and the total diameter reduction is 0.2-0.3mm.

[0009] Furthermore, it also includes step four: surface processing and aging treatment of the 1-2mm diameter wire; The surface processing and aging treatment include: The wire is straightened, cut to length, and ground without centering to remove oxide layer defects on the surface of the wire and make the wire glossy. Then, vacuum furnace heat treatment is used, with an aging temperature of 480-490℃ and an aging time of 8-10 hours. After aging, gas is immediately introduced into the furnace for cooling, and the furnace fan is turned on to stir within 3 minutes. The furnace is removed from the furnace when the temperature drops below 40℃.

[0010] Furthermore, in step one, forming the steel ingot into a coil with a diameter of 8-10 mm includes: Steel ingots are smelted using a vacuum induction furnace and a vacuum arc furnace, held at 1200-1250℃ for 24-48 hours for high-temperature homogenization, forged into 150-300mm square billets at 1150-950℃, and then hot-rolled into coils with a diameter of 8-10mm.

[0011] Furthermore, in step three, during the drawing cycle process, the single-pass diameter reduction in the later cycle is less than the single-pass diameter reduction in the previous cycle.

[0012] Furthermore, in step three, the number of pull-out cycle processes is three; In the first drawing cycle, the first intermediate wire is cold-drawn to a diameter of 4.5-5 mm, with a single-pass diameter reduction of 0.5-0.6 mm; In the second drawing cycle, the first intermediate wire is cold-drawn to a diameter of 2.5-3 mm, with a single-pass diameter reduction of 0.3-0.5 mm; In the third drawing cycle, the first intermediate wire is cold-drawn to a diameter of 1-2 mm, with a single-pass diameter reduction of 0.2-0.3 mm.

[0013] Furthermore, in step three, during the drawing cycle process, each online solution heat treatment is protected by argon gas. Alternatively, the holding time for the online solution heat treatment in the later cycle is shorter than the holding time for the online solution heat treatment in the previous cycle.

[0014] On the other hand, embodiments of the present invention also disclose a martensitic aging steel wire with a strength of 2.3 GPa or higher, having a diameter of 1-2 mm and a grain size of 3-6 µm; a yield strength Rp0.2 > 2.3 GPa, a tensile strength Rm > 2.4 GPa, and an elongation A ≥ 7%. Its microstructure is a recrystallized stable phase whose cold working stress has been completely eliminated, and it will not undergo microstructural transformation during subsequent repeated load-bearing use, thus reducing the material's service life.

[0015] Furthermore, the martensitic aging steel wire with a strength of 2.3 GPa or higher mentioned above is prepared using the aforementioned preparation method.

[0016] By adopting the above technical solution, the present invention has at least the following beneficial effects: This invention provides a martensitic aging steel wire with a strength of 2.3 GPa or higher and its preparation method, which can meet the demand for martensitic aging steel wire products with a strength of 2.3 GPa or higher in the 3C and precision equipment fields. By adjusting the drawing diameter reduction of the wire rod and wire in a gradient and by intermediate solution annealing treatment, martensitic aging steel wire products with a strength of Φ1.0~2.0 mm and a strength of 2.3 GPa or higher are drawn, so that the grain size of the wire is controlled at 3~6µm. The yield strength Rp0.2>2.3 GPa, the tensile strength Rm>2.4 GPa, and the elongation A≥5% of the wire after aging treatment are achieved. Furthermore, the preparation method is designed based on the equipment conditions of metal wire manufacturing manufacturers, which is easy to operate, has high production efficiency, and high product quality stability. Attached Figure Description

[0017] 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.

[0018] Figure 1 This is a flowchart of a method for preparing martensitic aging steel wire with a pressure of 2.3 GPa or higher, as disclosed in Embodiment 1 of the present invention. Figure 2This is a microstructure diagram of the martensitic aging steel wire with a pressure of 2.3 GPa or higher obtained in Example 1 of the present invention. Detailed Implementation

[0019] The embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of this disclosure by way of example, but should not be used to limit the scope of this disclosure. This disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0020] These embodiments are provided to make the disclosure thorough and complete, and to fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0021] It should be noted that, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationship, are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] Furthermore, the terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Terms such as "including" or "contains" mean that the element preceding the word encompasses the element listed after the word, and do not exclude the possibility of encompassing other elements as well.

[0023] It should also be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure depending on the specific circumstances. When a particular device is described as being located between a first device and a second device, an intermediary device may or may not be present between the particular device and the first or second device.

[0024] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0025] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0026] like Figure 1 As shown, some embodiments of the present invention disclose a method for preparing martensitic aging steel wire with a pressure of 2.3 GPa or higher, comprising: Step 1: Form the steel ingot into coils with a diameter of 8-10 mm. The steel ingots can be prepared using conventional methods, such as smelting them in a vacuum induction furnace or vacuum arc remelting furnace, holding them at 1200-1250℃ for 24-48 hours for high-temperature homogenization, forging them into 150-300 mm square billets at 1150-950℃, and then hot-rolling them into coils with a diameter of 8-10 mm. The steel ingot composition, by mass percentage, generally includes: Co 11.50-12.50%, Ni 18.00-19.00%, Mo 4.60-5.20%, Ti 1.30-1.60%, Al 0.05-0.15%, with the balance being Fe and unavoidable impurities.

[0027] Step 2: The coiled wire is subjected to solution treatment, cooled to room temperature, and then surface processed to obtain the first intermediate wire. The solution treatment temperature is preferably 820-830℃, the holding time is preferably 1.5-3 hours, and then air-cooled to room temperature. The surface processing includes peeling and polishing, with a total diameter reduction of 0.2-0.3 mm.

[0028] Step 3: Perform multiple drawing cycles on the first intermediate wire to obtain a wire with a diameter of 1-2 mm; wherein, the drawing cycle process includes: cold drawing followed by online solution heat treatment.

[0029] In a preferred embodiment, for the drawing cycle processing, the drawing amount in the later cycle is less than that in the earlier cycle, and the single-pass diameter reduction in the later cycle cannot be greater than that in the earlier cycle. Each online solution heat treatment requires argon protection, and the treatment temperature can be the same; the holding time for the online solution heat treatment in the later cycle is less than that in the earlier cycle.

[0030] In a further preferred embodiment, the number of drawing cycles can be three; specific process parameter control may include: In the first drawing cycle, the first intermediate wire is cold-drawn to a diameter of 4.5-5 mm, with a single-pass diameter reduction of 0.5-0.6 mm; In the second drawing cycle, the first intermediate wire is cold-drawn to a diameter of 2.5-3 mm, with a single-pass diameter reduction of 0.3-0.5 mm; In the third drawing cycle, the first intermediate wire is cold-drawn to a diameter of 1-2 mm, with a single-pass diameter reduction of 0.2-0.3 mm. The temperature of the online solution heat treatment in the three-stage Laban cycle process is controlled at 820℃.

[0031] Step 4: To further improve product quality, the 1-2mm diameter wire can be surface-processed and aged. The surface-processing and aging treatment may include: straightening, cutting to length, and centerless grinding of the wire to remove defects such as the oxide layer on the surface of the wire, so that the wire reaches a bright state; then, vacuum furnace heat treatment is carried out at an aging temperature of 490℃ for 8 hours. After the aging is completed, gas is immediately introduced into the furnace for cooling, and the furnace fan is turned on for stirring within 3 minutes. The furnace temperature is reduced to 40℃ before the wire is taken out of the furnace.

[0032] The preparation method disclosed in the above embodiments of the present invention, through gradient adjustment of the drawing diameter reduction of wire rod and wire and intermediate solution annealing treatment, can draw and prepare martensitic aging steel wire products with a diameter of 1.0~2.0mm and a Pa value of 2.3GPa or higher. The grain size of the wire reaches 3~6µm. The yield strength Rp0.2>2.3GPa, tensile strength Rm>2.4GPa, and elongation A≥7% of the wire after aging treatment. This material can be widely used in hinges, shafts, and precision equipment shafts in the 3C electronics field, with broad application prospects.

[0033] Some embodiments of this invention also disclose a method for preparing martensitic aging steel wire with a strength of 2.3 GPa or higher. This method can meet the demand for martensitic aging steel wire products with a strength of 2.3 GPa or higher in the 3C and precision equipment fields. The components, by mass percentage, include: Co 11.50–12.50%, Ni 18.00–19.00%, Mo 4.60–5.20%, Ti 1.30–1.60%, Al 0.05–0.15%, with the balance being Fe and unavoidable impurities. The steel ingot is smelted using a vacuum induction furnace + vacuum arc remelting furnace, held at 1200–1250℃ for 24–48 hours for high-temperature homogenization, forged into 150–300 mm square billets at 1150–950℃, and then hot-rolled into Φ8–10 mm coils.

[0034] Next, the Φ8~10mm hot-rolled wire rods are subjected to solution treatment. The solution treatment process is as follows: hold at 820~830℃ for 1.5~3.0 hours, and then air cool to room temperature. After solution treatment, surface processing is performed: the solution-treated coil (first intermediate wire) is peeled and polished, with a diameter reduction of 0.2~0.3mm; After surface finishing, the material enters a drawing cycle, which specifically includes: First cold drawing: The bright disc is cold drawn to Φ4.5~5.0mm, with a single-pass diameter reduction of 0.5~0.6mm; First online solution heat treatment: The process is as follows: hold at 820℃ for 20~25min, with argon gas protection during the online solution treatment process, and air cooling after the holding period. Second cold drawing: The bright intermediate wire is cold drawn to Φ2.5~3.0mm, with a single-pass diameter reduction of 0.3~0.5mm; Second online solution heat treatment: The process is as follows: hold at 820℃ for 12~15min, with argon gas protection during the online solution treatment process, and air cooling after the heat treatment is completed; Third cold drawing: The bright intermediate wire is cold drawn to Φ1.0~2.0mm, with a single-pass diameter reduction of 0.2~0.3mm; Third online solution heat treatment: The process is as follows: heat treatment at 820℃ for 7~10min, with argon gas protection during the online solution treatment process, and air cooling after heat treatment.

[0035] In this embodiment, by adjusting the drawing diameter reduction of wire rod and wire and using intermediate solution annealing, martensitic aging steel wire products with a diameter of 1.0~2.0mm and a strength of 2.3GPa or higher are drawn and prepared. The grain size of the wire reaches 3~6µm. The yield strength Rp0.2>2.3GPa, the tensile strength Rm>2.4GPa, and the elongation A≥7% of the wire after aging treatment are achieved.

[0036] This invention also discloses a method for preparing martensitic aging steel wire with a strength of 2.3 GPa or higher, comprising: The components, by mass percentage, include: Co 11.50–12.50%, Ni 18.00–19.00%, Mo 4.60–5.20%, Ti 1.30–1.60%, Al 0.05–0.15%, with the balance being Fe and unavoidable impurities.

[0037] The main process of billet preparation is as follows: steel ingots are smelted using a vacuum induction furnace and a vacuum arc furnace, held at 1200~1250℃ for 24~48 hours for high-temperature homogenization, forged into 150~300mm square billets at 1150~950℃, and then hot rolled into Φ8~10mm coils.

[0038] The method for preparing the filament is as follows: Step 1: Solution treatment of raw materials Φ8~10mm hot-rolled wire rods are solution treated in a pit furnace. The furnace temperature is below 400℃ when the material is charged, and the temperature is increased to 820~830℃ at a rate of 10℃ / min. The temperature is held for 1.5~3.0 hours, and then the material is air-cooled to room temperature. At this stage, the martensitic aging steel is in the state of Φ8~10mm wire rods. Since the grain size of the microstructure is sensitive to the solution treatment temperature: if the solution treatment temperature is below 820℃, the solution is insufficient, which will cause difficulties in subsequent drawing or drawing fracture; if the solution treatment temperature is above 830℃, the grain size of the microstructure will be too large, which will affect the grain size of the subsequent wire product and reduce its strength and toughness.

[0039] Step 2: Surface Processing The solution-treated wire rods undergo peeling and polishing, reducing the diameter by 0.2~0.3mm. This process removes the oxide layer and other defects from the wire rod surface, bringing it to a bright finish. Diameter reduction = original diameter - processed diameter.

[0040] Step 3: First cold drawing The bright disc is cold-drawn to an intermediate size of Φ4.5~5.0mm, with a single-pass diameter reduction of 0.5~0.6mm and a drawing speed of 6~8m / min; Step 4: First intermediate annealing solution heat treatment Intermediate solution annealing is performed in an online heat treatment furnace with argon protection activated. The wire feeding begins at a furnace temperature of 820℃~830℃, and the holding time is 20~25 minutes. After the holding time is completed, the wire is removed from the furnace and allowed to air cool naturally. Step 5: Surface polishing treatment: The intermediate solution-annealed wire is subjected to surface polishing treatment with a single-pass diameter reduction of 0.1 mm to remove oxide layer defects on the wire surface and make the wire surface glossy. Step Six: Second Cold Drawing The intermediate solution-annealed wire is cold-drawn to Φ2.5~3.0mm, with a single-pass diameter reduction of 0.3~0.5mm and a drawing speed of 8~10m / min; Step 7: Second intermediate solution annealing heat treatment Intermediate solution annealing is performed in an online heat treatment furnace with argon protection activated. The wire feeding begins at a furnace temperature of 820℃~830℃ and is held for 12~15 minutes. After holding, the wire is removed from the furnace and allowed to air cool naturally. Step 8: Third cold drawing The intermediate solution-annealed wire is cold-drawn to Φ1.0~2.0mm, with a single-pass diameter reduction of 0.2~0.3mm and a drawing speed of 10~12m / min; Step 9: Final solution annealing heat treatment The final solution annealing treatment was performed in an online heat treatment furnace with argon protection. Wire drawing began at a furnace temperature of 820℃~830℃, and the holding time was 7~10 minutes. After holding, the wire was removed from the furnace and allowed to air cool naturally. For this martensitic aging steel wire with a diameter of Φ1.0~2.0mm, the grain size is highly sensitive to the solution treatment temperature: if the solution treatment temperature is below 820℃, insufficient solution is produced, leading to difficulties in subsequent drawing or drawing breakage; if the solution treatment temperature is above 830℃, the grain size is too large, affecting the grain size of the finished wire and reducing its strength and toughness.

[0041] Step 10: Surface Processing The solid solution-treated wire is straightened, cut to length, and centerless ground. The diameter reduction is 0.05~0.08mm. Defects such as the oxide layer on the surface of the wire are removed to make the wire glossy. The product grain size is controlled at 3~6µm.

[0042] The filament obtained in step ten is subjected to aging treatment. The aging heat treatment process is as follows: vacuum furnace heat treatment is used, with an aging temperature of 490~530℃ and an aging time of 3~8 hours. After aging, gas is immediately introduced into the furnace for cooling, and the furnace fan is turned on for stirring within 1~5 minutes. The furnace temperature is cooled to below 50℃ before being removed from the furnace. The yield strength Rp0.2>2.3GPa, tensile strength Rm>2.4GPa, and elongation A≥7% of the obtained filament are as follows.

[0043] This embodiment successfully prepared maraging steel wire with a grain size of 3-6µm through solution treatment and cold drawing. The yield strength Rp0.2>2.3GPa, tensile strength Rm>2.4GPa, and elongation A≥7% of the aged wire. The finished maraging steel wire has a diameter of Φ1.0-2.0mm, a length of 2-2.5m, a dimensional accuracy of -0.02mm or ±0.01mm, an ellipticity ≤0.01mm, and a straightness of 0.5mm / 2.0m or 0.5mm / 2.5m. The drawing and heat treatment method for maraging steel in this embodiment is designed based on the equipment conditions of the metal wire manufacturing plant and has the advantages of easy operation, high production efficiency, and high product quality stability.

[0044] The present invention will be described below through specific embodiments and comparative examples. The raw materials used in each embodiment and comparative example are martensitic aging steel with a pressure of 2.3 GPa or higher. The components, by mass percentage, include: Co 11.50–12.50%, Ni 18.00–19.00%, Mo 4.60–5.20%, Ti 1.30–1.60%, Al 0.05–0.15%, with the balance being Fe and unavoidable impurities. The main process for billet preparation is as follows: steel ingots are smelted using a vacuum induction furnace and a vacuum arc furnace; high-temperature homogenization is performed at 1200–1250℃ for 24–48 hours; forging is carried out at 1150–950℃ into 150–300 mm square billets; and then hot-rolling is performed into Φ8–10 mm coils.

[0045] Example 1 This embodiment provides a martensitic aging steel wire with a pressure of 2.3 GPa or higher and its preparation method. The specific steps are as follows: Step 1, Solution treatment of hot-rolled wire rod: The Φ8mm hot-rolled wire rod is solution treated in a pit furnace. The furnace temperature is 100℃ when the material is loaded, and the temperature is increased to 820℃ at 10℃ / min. The temperature is held for 1.5 hours, and then the wire rod is removed from the furnace and air-cooled to room temperature. Step 2, Surface Finishing: The Φ8mm solution-treated wire rod is peeled and polished, reducing the diameter by 0.2mm. This removes the oxide layer and other defects from the wire rod surface, bringing it to a glossy finish. Diameter reduction = Original diameter - Finished diameter.

[0046] Step 3, First cold drawing: The Φ7.8mm bright disc is cold drawn to the intermediate size of Φ4.5mm. The diameter reduction in a single pass is 0.6mm, 0.6mm, 0.6mm, 0.6mm, 0.5mm, and 0.5mm respectively, and the drawing speed is 8m / min. Step 4: First intermediate solution annealing heat treatment: Intermediate solution annealing is performed in an online heat treatment furnace. Argon protection is turned on, the furnace temperature is 820℃, wire feeding begins, the holding time is 20 minutes, and after the holding time is completed, the wire is naturally air-cooled after being taken out of the furnace. Step 5, Surface polishing treatment: The intermediate solution annealed wire is subjected to surface polishing treatment, with a single pass diameter reduction of 0.1 mm, to remove oxide layer defects on the wire surface and make the wire surface glossy. Step 6, Second cold drawing: The polished intermediate wire is cold drawn to Φ2.5mm, with single-pass diameter reductions of 0.5mm, 0.5mm, 0.4mm, and 0.3mm respectively, and a drawing rate of 10m / min; Step 7, Second intermediate solution annealing heat treatment: Intermediate solution annealing is performed in an online heat treatment furnace. Argon protection is turned on, the furnace temperature is 820℃, wire feeding begins, the holding time is 12 minutes, and after the holding time is completed, the wire is naturally air-cooled after being taken out of the furnace. Step 8, Third cold drawing: The Φ2.5 intermediate solution annealed wire is cold drawn to Φ1.0mm, with single-pass diameter reduction of 0.3mm, 0.3mm, 0.2mm, 0.2mm, and 0.2mm respectively, and the drawing rate is 12m / min; Step 9, Final Solution Annealing Heat Treatment: The final solution annealing treatment is carried out in an online heat treatment furnace. Argon protection is turned on, the furnace temperature is 820℃, the wire feeding begins, the holding time is 7 minutes, and after the holding time is completed, the wire is naturally air-cooled after being taken out of the furnace.

[0047] Step 10, Surface processing: The solution-treated wire is straightened, cut to length, and ground without centering. The diameter is reduced by 0.05mm during grinding to remove defects such as the oxide layer on the surface of the wire, so that the wire reaches a bright state.

[0048] Step 11, Aging Treatment: The wire material obtained in Step 10 is subjected to aging treatment. The aging heat treatment process is as follows: vacuum furnace heat treatment is used, the aging temperature is 490℃, the aging time is 8 hours, and gas is immediately introduced into the furnace for cooling after aging. The furnace fan is turned on for stirring within 3 minutes, and the furnace temperature is reduced to 40℃ before the wire is taken out of the furnace.

[0049] The grain size, microhardness, and mechanical properties of the obtained martensitic aged steel wire in the solid solution state are shown in Table 1 below. Micrographs of the obtained martensitic aged steel wire in the solid solution state are shown below. Figure 2 As shown.

[0050] Example 2 This embodiment provides a martensitic aging steel wire with a pressure of 2.3 GPa or higher and its preparation method. The specific steps are as follows: Step 1, Solution treatment of wire rod: The Φ10mm hot-rolled wire rod is solution treated in a pit 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 3 hours, and then the wire rod is removed from the furnace and air-cooled to room temperature. Step 2, Surface Finishing: The Φ10mm solution-treated wire rod is peeled and polished, reducing the diameter by 0.3mm. This removes the oxide layer and other defects from the wire rod surface, bringing it to a bright finish. Diameter reduction = Original diameter - Finished diameter.

[0051] Step 3, First cold drawing: The Φ9.7mm bright circular disc is cold drawn to the intermediate size of Φ5.0mm. The diameter reduction in a single pass is 0.6mm, 0.6mm, 0.6mm, 0.6mm, 0.6mm, 0.6mm, 0.6mm, 0.5mm, and the drawing speed is 6m / min. Step 4: First intermediate solution annealing heat treatment: Intermediate solution annealing is performed in an online heat treatment furnace. Argon protection is turned on, the furnace temperature is 820℃, wire feeding begins, the holding time is 25 minutes, and after the holding time is completed, the wire is removed from the furnace and allowed to air cool naturally. Step 5, Surface polishing treatment: The intermediate solution annealed wire is subjected to surface polishing treatment, with a single pass diameter reduction of 0.1 mm, to remove oxide layer defects on the wire surface and make the wire surface glossy. Step 6, Second cold drawing: The polished intermediate wire is cold drawn to Φ3.0mm, with single-pass diameter reductions of 0.5mm, 0.5mm, 0.4mm, 0.3mm, and 0.3mm respectively, and a drawing rate of 8m / min; Step 7, Second intermediate solution annealing heat treatment: Intermediate solution annealing treatment is carried out in an online heat treatment furnace. Argon protection is turned on, the furnace temperature is 820℃, the wire feeding begins, the holding time is 15min, and after the holding time is completed, the wire is naturally air-cooled after being taken out of the furnace. Step 8, Third cold drawing: The Φ3.0 intermediate solution annealed wire is cold drawn to Φ2.0mm, with single-pass diameter reduction of 0.3mm, 0.3mm, 0.2mm and 0.2mm respectively, and the drawing rate is 10m / min; Step 9, Final Solution Annealing Heat Treatment: The final solution annealing treatment is carried out in an online heat treatment furnace. Argon protection is turned on, the furnace temperature is 820℃, the wire feeding begins, the holding time is 9 minutes, and after the holding time is completed, the wire is naturally air-cooled after being taken out of the furnace.

[0052] Step 10, Surface Processing: The solution-treated wire is straightened, cut to length, and then centerlessly ground. The diameter reduction is 0.08mm. Defects such as the oxide layer on the surface of the wire are removed to make the wire glossy.

[0053] Step 11, Aging Treatment: The wire material obtained in Step 10 is subjected to aging treatment. The aging heat treatment process is as follows: vacuum furnace heat treatment is used, the aging temperature is 510℃, the aging time is 4 hours, and gas is immediately introduced into the furnace for cooling after aging. The furnace fan is turned on for stirring within 3 minutes, and the furnace temperature is reduced to 40℃ before the wire is taken out of the furnace.

[0054] The grain size, microhardness, and mechanical properties of the obtained martensitic aged steel wire in the solid solution state are shown in Table 1 below.

[0055] Example 3 This embodiment provides a martensitic aging steel wire with a pressure of 2.3 GPa or higher and its preparation method. The specific steps are as follows: Step 1, Solution treatment of hot-rolled coils: The Φ9mm hot-rolled coils are solution treated in a pit furnace. The furnace temperature is 300℃ when the material is loaded, and the temperature is increased to 820℃ at a rate of 10℃ / min. The temperature is held for 2 hours, and then the coils are removed from the furnace and air-cooled to room temperature.

[0056] Step 2, Surface Finishing: The Φ9mm solution-treated wire rod is peeled and polished, reducing the diameter by 0.25mm. This removes the oxide layer and other defects from the surface of the wire rod, bringing it to a bright finish. Diameter reduction = Original diameter - Finished diameter.

[0057] Step 3, First cold drawing: The Φ8.75mm bright disc is cold drawn to the intermediate size of Φ4.55mm. The diameter reduction in a single pass is 0.6mm, 0.6mm, 0.6mm, 0.6mm, 0.6mm, 0.6mm, 0.6mm, and 0.6mm respectively, and the drawing speed is 7m / min.

[0058] Step 4: First intermediate solution annealing heat treatment: Perform intermediate solution annealing in an online heat treatment furnace, turn on argon protection, start wire feeding at furnace temperature of 820℃, hold for 20 minutes, and allow to air cool naturally after removal from the furnace.

[0059] Step 5, Surface polishing treatment: The intermediate solution annealed wire is subjected to surface polishing treatment, with a single pass diameter reduction of 0.1 mm, to remove oxide layer defects on the wire surface and make the wire surface glossy. Step 6, Second cold drawing: The polished intermediate wire is cold drawn to Φ2.5mm, with single-pass diameter reductions of 0.5mm, 0.5mm, 0.5mm, and 0.45mm respectively, and a drawing rate of 9m / min; Step 7, Second intermediate solution annealing heat treatment: Intermediate solution annealing is performed in an online heat treatment furnace. Argon protection is turned on, the furnace temperature is 820℃, wire feeding begins, the holding time is 12 minutes, and after the holding time is completed, the wire is naturally air-cooled after being taken out of the furnace.

[0060] Step 8, Third cold drawing: The Φ2.5 intermediate solution annealed wire is cold drawn to Φ1.6mm, with single-pass diameter reduction of 0.3mm, 0.3mm, and 0.3mm respectively, and the drawing rate is 12m / min; Step 9, Final Solution Annealing Heat Treatment: The final solution annealing treatment is carried out in an online heat treatment furnace. Argon protection is turned on, the furnace temperature is 820℃, the wire feeding begins, the holding time is 8 minutes, and after the holding time is completed, the wire is naturally air-cooled after being taken out of the furnace.

[0061] Step 10: Surface processing: The solution-treated wire is subjected to centerless grinding, with a diameter reduction of 0.06 mm, to remove defects such as the oxide layer on the surface of the wire, so that the wire reaches a bright state.

[0062] Step 11, Aging Treatment: The wire material obtained in Step 10 is subjected to aging treatment. The aging heat treatment process is as follows: vacuum furnace heat treatment is used, the aging temperature is 530℃, the aging time is 3 hours, and gas is immediately introduced into the furnace for cooling after aging. The furnace fan is turned on for stirring within 2 minutes, and the furnace temperature is reduced to 40℃ before the wire is taken out of the furnace.

[0063] Comparative Example 1 This embodiment provides a martensitic aging steel wire with a pressure of 2.3 GPa or higher and its preparation method. The specific steps are as follows: Step 1, Solution treatment of hot-rolled coils: The Φ9mm hot-rolled coils are solution treated in a pit furnace. The furnace temperature is 300℃ when the material is loaded, and the temperature is increased to 820℃ at a rate of 10℃ / min. The temperature is held for 2 hours, and then the coils are removed from the furnace and air-cooled to room temperature.

[0064] Step 2, Surface Finishing: The Φ9mm solution-treated wire rod is peeled and polished, reducing the diameter by 0.25mm. This removes the oxide layer and other defects from the surface of the wire rod, bringing it to a bright finish. Diameter reduction = Original diameter - Finished diameter.

[0065] Step 3, First cold drawing: The Φ8.75mm bright disc is cold drawn to the intermediate size of Φ4.55mm. The diameter reduction in a single pass is 0.6mm, 0.6mm, 0.6mm, 0.6mm, 0.6mm, 0.6mm, 0.6mm, and 0.6mm respectively, and the drawing speed is 7m / min.

[0066] Step 4: First intermediate solution annealing heat treatment: Perform intermediate solution annealing in an online heat treatment furnace, turn on argon protection, start wire feeding at furnace temperature of 850℃, hold for 20 minutes, and allow to air cool naturally after removal from the furnace.

[0067] Step 5, Surface polishing treatment: The intermediate solution annealed wire is subjected to surface polishing treatment, with a single pass diameter reduction of 0.1 mm, to remove oxide layer defects on the wire surface and make the wire surface glossy. Step 6, Second cold drawing: The polished intermediate wire is cold drawn to Φ2.5mm, with single-pass diameter reductions of 0.5mm, 0.5mm, 0.5mm, and 0.45mm respectively, and a drawing rate of 9m / min; Step 7, Second intermediate solution annealing heat treatment: Intermediate solution annealing treatment is carried out in an online heat treatment furnace. Argon protection is turned on, the furnace temperature is 850℃ to start wire feeding, the holding time is 12min, and after the holding time is completed, the wire is naturally air-cooled after being taken out of the furnace.

[0068] Step 8, Third cold drawing: The Φ2.5 intermediate solution annealed wire is cold drawn to Φ1.6mm, with single-pass diameter reduction of 0.3mm, 0.3mm, and 0.3mm respectively, and the drawing rate is 12m / min; Step 9, Final Solution Annealing Heat Treatment: The final solution annealing treatment is carried out in an online heat treatment furnace. Argon protection is turned on, the furnace temperature is 850℃, the wire feeding begins, the holding time is 8 minutes, and after the holding time is completed, the wire is removed from the furnace and allowed to air cool naturally.

[0069] Step 10: Surface processing: The solution-treated wire is subjected to centerless grinding, with a diameter reduction of 0.06 mm, to remove defects such as the oxide layer on the surface of the wire, so that the wire reaches a bright state.

[0070] Step 11, Aging Treatment: The wire material obtained in Step 10 is subjected to aging treatment. The aging heat treatment process is as follows: vacuum furnace heat treatment is used, the aging temperature is 530℃, the aging time is 3 hours, and gas is immediately introduced into the furnace for cooling after aging. The furnace fan is turned on for stirring within 2 minutes, and the furnace temperature is reduced to 40℃ before the wire is taken out of the furnace.

[0071] The grain size, microhardness, and mechanical properties of the obtained martensitic aged steel wire in the solid solution state are shown in Table 1 below.

[0072] Table 1

[0073] In summary, the martensitic aging steel wire with a strength of 2.3 GPa or higher and its preparation method provided by this invention can produce martensitic aging steel wire with a grain size controlled at 3~6 µm, a yield strength Rp0.2>2.3 GPa, a tensile strength Rm>2.4 GPa, and an elongation A≥7%. Furthermore, the finished wire meets the stringent requirements for wire size and surface quality in the high-end 3C and precision equipment component fields. The solution treatment and heat treatment methods disclosed in this invention are designed based on the equipment conditions of metal wire manufacturing plants, are easy to operate, and have high production efficiency. This invention has significant practical implications for the development of my country's high-end 3C field.

[0074] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0075] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner.

Claims

1. A method of producing a maraging steel wire material of 2.3 GPa or more, characterized by, include: Step 1: Shape the steel ingot into a disc with a diameter of 8-10mm; Step 2: The coil is solution treated, cooled to room temperature, and then surface processed to obtain the first intermediate filament. Step 3: Perform multiple drawing cycles on the first intermediate wire to obtain a wire with a diameter of 1-2 mm; The drawing cycle process includes: cold drawing followed by online solution heat treatment; Furthermore, in step three, during the drawing cycle treatment, the drawing amount in the later cycle is less than that in the previous cycle, and the online solution treatment temperature is 815-825℃.

2. The production method according to claim 1, characterized by, The steel ingot composition, by mass percentage, includes: Co 11.50-12.50%, Ni 18.00-19.00%, Mo 4.60-5.20%, Ti 1.30-1.60%, Al 0.05-0.15%, with the balance being Fe and unavoidable impurities.

3. The preparation method according to claim 1, characterized in that, In step two, the solution treatment temperature is 820-830℃, the holding time is 1.5-3 hours, and then it is air-cooled to room temperature; the surface processing includes peeling and polishing, and the total diameter reduction is 0.2-0.3mm.

4. The method of claim 1, wherein, It also includes step four, which involves surface processing and aging treatment of the 1-2 mm diameter wire. The surface processing and aging treatment include: The wire is straightened, cut to length, and ground without centering to remove oxide layer defects on the surface of the wire and make the wire glossy. Then, vacuum furnace heat treatment is used, with an aging temperature of 480-490℃ and an aging time of 8-10 hours. After aging, gas is immediately introduced into the furnace for cooling, and the furnace fan is turned on to stir within 3 minutes. The furnace is removed from the furnace when the temperature drops below 40℃.

5. The preparation method according to claim 1, characterized in that, Step one, which involves shaping the steel ingot into coils with a diameter of 8-10 mm, includes: Steel ingots are smelted using a vacuum induction furnace and a vacuum arc furnace, held at 1200-1250℃ for 24-48 hours for high-temperature homogenization, forged into 150-300mm square billets at 1150-950℃, and then hot-rolled into coils with a diameter of 8-10mm.

6. The method of claim 1, wherein, In step three, during the drawing cycle process, the single-pass diameter reduction in the later cycle is less than the single-pass diameter reduction in the previous cycle.

7. The preparation method according to claim 1, characterized in that, In step three, the pulling cycle is performed three times; In the first drawing cycle, the first intermediate wire is cold-drawn to a diameter of 4.5-5 mm, with a single-pass diameter reduction of 0.5-0.6 mm; In the second drawing cycle, the first intermediate wire is cold-drawn to a diameter of 2.5-3 mm, with a single-pass diameter reduction of 0.3-0.5 mm; In the third drawing cycle, the first intermediate wire is cold-drawn to a diameter of 1-2 mm, with a single-pass diameter reduction of 0.2-0.3 mm.

8. The preparation method according to claim 7, characterized in that, In step three, during the drawing cycle process, each online solution heat treatment is protected by argon gas. Alternatively, the holding time for the online solution heat treatment in the later cycle is shorter than the holding time for the online solution heat treatment in the previous cycle.

9. A maraging steel wire material of 2.3 GPa or more, characterized by, It is prepared by the method for preparing martensitic aging steel wire with a strength of 2.3 GPa or higher as described in any one of claims 1-8.

10. The maraging steel wire of claim 9, wherein The diameter is 1-2 mm, the grain size is 3-6 µm; the yield strength Rp0.2>2.3 GPa, the tensile strength Rm>2.4 GPa, and the elongation A≥7%.

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