A method for manufacturing multi-layer composite structure stainless steel wire

Abstract

The present invention belongs to the technical field of stainless steel wires and discloses a method for manufacturing stainless steel wire with a multi-layer composite structure. The method comprises a central core material, an intermediate transition layer and an outer wear-resistant layer. The central core material is a high-strength stainless steel wire with a tensile strength of not less than 1200 MPa and a diameter of 2 mm. The intermediate transition layer is wrapped around the outer periphery of the central core material. The intermediate transition layer is a stainless steel alloy layer with a specific alloy composition and a thickness of 0.5 mm. The alloy composition ratio in the intermediate transition layer is: 18%-22% chromium, 8%-12% nickel, 2%-4% molybdenum, 1.5%-2.5% manganese, 0.5%-1.5% silicon, 0.3%-0.8% copper, and trace amounts of 0.05%-0.15% niobium and 0.03%-0.08% vanadium. The outer wear-resistant layer is coated around the outer periphery of the intermediate transition layer. The present invention solves the problem that stainless steel wire with a single structure in the prior art is difficult to meet the stringent requirements in terms of high strength, high wear resistance, good corrosion resistance and excellent comprehensive mechanical properties. The present invention is suitable for stainless steel wire.

Description

Technical Field

[0001] The present invention relates to the technical field of stainless steel wires, in particular to a method for manufacturing stainless steel wires with a multi-layer composite structure. Background Art

[0002] In existing stainless steel wire preparation technology, relatively simple and conventional process parameters and material selection are usually adopted, which is significantly different from the manufacturing method of the multi-layer composite structure stainless steel wire of the present invention, resulting in difficulty in achieving the excellent effect achieved by the present invention in product performance.

[0003] For example, in the preparation of the central core material, the existing technology generally heats the 304 stainless steel billet to 900°C-1000°C with a holding time of only 1-1.5 hours, and then adopts a wire drawing process with fewer passes, and the compression ratio of the wire drawing die is fixed at about 1.2, the work hardening rate is controlled at 20%-25%, and after drawing, it is naturally cooled in the air or simply air-cooled. This method results in limited grain refinement of the core material and uneven internal structure, which ultimately results in a tensile strength of generally only 500MPa-700MPa, which is far lower than the tensile strength requirement of not less than 1200MPa for the core material in the present invention, and cannot meet the strength requirements of the stainless steel wire under high stress conditions.

[0004] For the preparation of the intermediate transition layer, the existing technology may use ordinary thermal spraying methods, such as arc spraying. Parameters such as gas flow rate and powder feed rate cannot be precisely controlled, and the spraying distance and spray gun movement speed are also relatively arbitrary. Generally, the hydrogen flow rate is 10L / min-12L / min, the oxygen flow rate is 20L / min-25L / min, the powder feed rate is 20g / min-25g / min, the spraying distance is 100mm-120mm, and the spray gun movement speed is 200mm / s-300mm / s. No subsequent precise thermal diffusion treatment is performed or the thermal diffusion conditions are roughly controlled. The thermal diffusion temperature is 800℃-900℃, the time is 1-2 hours, and the heating rate and cooling rate are also unstable. The resulting transition layer and core material have a relatively low bonding strength, typically between 100 MPa and 200 MPa. This easily leads to delamination during use, and the stability of the multilayer structure cannot be guaranteed. This is far from the bonding strength requirement of not less than 300 MPa in the present invention, significantly impacting the reliability and service life of the product.

[0005] When preparing the outer wear-resistant layer, the electroplating process can cause environmental pollution problems, and the coating thickness is uneven, generally ranging from 0.1mm to 0.2mm. The hardness is also relatively low, between 400HV and 500HV, and the wear resistance is limited. In the simple coating process, the deposition rate cannot be precisely controlled, ranging from 5μm / h to 8μm / h. The deposition temperature and pressure are unstable, ranging from 300℃ to 350℃ and 1Pa to 1.5Pa, respectively. The introduced wear-resistant particles are unevenly distributed, with a volume ratio of generally 5% to 8%. Without effective ultrasonic dispersion treatment, the wear resistance of the outer wear-resistant layer and its bonding performance with the transition layer are both poor. It cannot be compared with the high hardness (600HV), uniform wear resistance, and tightly bonded outer wear-resistant layer prepared by the precise magnetron sputtering deposition process of the present invention. This seriously limits the service life and performance of the stainless steel wire under high friction conditions.

[0006] In summary, the prior art has many deficiencies in the process parameters and methods for preparing stainless steel wire. Compared with the present invention, there is a significant gap in product strength, bonding strength, wear resistance, and stability and reliability of comprehensive performance, and it cannot meet the growing demand of modern industry for high-performance stainless steel wire. Therefore, the manufacturing method of the multi-layer composite structure stainless steel wire of the present invention has significant innovation and practical value. Summary of the Invention

[0007] The present invention aims to provide a method for manufacturing a multi-layer composite structure stainless steel wire to solve the problem that the existing single structure stainless steel wire is difficult to meet the stringent requirements of high strength, high wear resistance, good corrosion resistance and excellent comprehensive mechanical properties.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] The technical solution provided by the present invention is: a method for manufacturing a multi-layer composite structure stainless steel wire, comprising a central core material, an intermediate transition layer and an outer wear-resistant layer;

[0010] The manufacturing method of the multi-layer composite structure stainless steel wire is as follows:

[0011] S1: Preparation of the central core material: Select a stainless steel billet that meets the 304 stainless steel standard, heat it to 1100-1200°C, and keep it warm for 2-3 hours to homogenize the billet;

[0012] A multi-pass wire drawing process is used, with online tension detection and adjustment after each drawing pass. The initial compression ratio of the drawing die is 1.3, and the wire drawing is performed in increments of 0.1 each time until the stainless steel billet is processed into a high-strength stainless steel wire with a diameter of 2mm. The work hardening rate is controlled between 30% and 40% during the wire drawing process.

[0013] The drawn stainless steel wire is subjected to annealing heat treatment under a protective atmosphere of argon, the annealing temperature is 800°C-900°C, the annealing time is 2 hours, and the cooling rate is controlled at 50°C / h-80°C / h;

[0014] S2: Coating and thermal diffusion of the intermediate transition layer: The alloy powder is accurately prepared according to the alloy composition ratio of the intermediate transition layer, and the intermediate transition layer alloy powder is sprayed on the periphery of the central core material using the supersonic flame spraying process. During supersonic flame spraying, hydrogen and oxygen are used as fuel gases, with a hydrogen flow rate of 15L / min-20L / min, an oxygen flow rate of 30L / min-40L / min, a powder feed rate of 30g / min-40g / min, a spraying distance of 150mm-200mm, and a spray gun moving speed of 300mm / s-500mm / s, so that the spraying thickness reaches 0.5mm;

[0015] The sprayed composite wire is placed in a vacuum thermal diffusion furnace and subjected to thermal diffusion treatment in an environment with a vacuum degree better than 5×10⁻³Pa. The thermal diffusion temperature is 1000℃-1100℃, the thermal diffusion time is 3 hours, the heating rate is 10℃ / min-15℃ / min, and the cooling rate is 8℃ / min-12℃ / min, so that the intermediate transition layer and the central core material form a firm bond;

[0016] S3: The outer wear-resistant layer is deposited on the periphery of the intermediate transition layer by magnetron sputtering deposition process. The sputtering target material is an alloy target material that matches the composition of the outer wear-resistant layer alloy. The deposition process is controlled at a deposition rate of 10μm / h-15μm / h, a deposition temperature of 400℃-500℃, and a deposition pressure of 2Pa-3Pa.

[0017] During the deposition process, tungsten carbide particles are introduced synchronously through a powder introduction device. Before introduction, the tungsten carbide particles are subjected to ultrasonic dispersion treatment. The dispersion medium of the tungsten carbide particles is anhydrous ethanol, the ultrasonic frequency is 20kHz-30kHz, and the ultrasonic time is 30min-60min, so that the tungsten carbide particles are evenly dispersed in the outer wear-resistant layer, and finally an outer wear-resistant layer with a thickness of 0.3mm is formed;

[0018] S4: The prepared stainless steel wire is subjected to final heat treatment under nitrogen protection atmosphere, with a heat treatment temperature of 500℃-600℃, a heat treatment time of 1 hour, a heating rate of 12℃ / min-18℃ / min, and a furnace cooling method to improve the overall performance of the steel wire. Finally, the prepared multi-layer composite structure stainless steel wire is obtained.

[0019] Furthermore, in S2, the thermal spraying process adopts supersonic flame spraying, the gas flow rate during spraying is 15L / min-20L / min, and the powder feeding amount is 30g / min-40g / min.

[0020] Furthermore, in S3, the physical vapor deposition process is magnetron sputtering deposition, the sputtering power is 1000W-1500W, and the distance between the target and the steel wire is 80mm.

[0021] Furthermore, an intermediate transition layer is wrapped around the outer periphery of the central core material. The intermediate transition layer is a stainless steel alloy layer with a specific alloy composition. Its thickness is 0.5 mm. The alloy composition ratio in the intermediate transition layer is: chromium 18%-22%, nickel 8%-12%, molybdenum 2%-4%, manganese 1.5%-2.5%, silicon 0.5%-1.5%, copper 0.3%-0.8% and trace amounts of niobium 0.05%-0.15% and vanadium 0.03%-0.08%, and the remainder is Fe and unavoidable impurities. The intermediate transition layer and the central core material are bonded by thermal diffusion, and the bonding strength is not less than 300 MPa.

[0022] Furthermore, the central core material is a high-strength stainless steel wire with a tensile strength of not less than 1200 MPa and a diameter of 2 mm.

[0023] Furthermore, the outer wear-resistant layer is coated on the outer periphery of the middle transition layer. The outer wear-resistant layer is a stainless steel wear-resistant alloy layer that has undergone special heat treatment. Its thickness is 0.3mm and its hardness is 600HV. The outer wear-resistant layer and the middle transition layer are combined through a physical vapor deposition process to form a dense bonding interface, and the element diffusion depth at the bonding interface is 0.05mm.

[0024] Furthermore, the stainless steel material of the central core material is 304 stainless steel.

[0025] Furthermore, the stainless steel alloy composition of the intermediate transition layer also includes 0.5%-1.5% titanium, and the titanium element forms a titanium-rich diffusion layer at the interface between the intermediate transition layer and the central core material, and the thickness of the titanium-rich diffusion layer is 0.02 mm.

[0026] Furthermore, tungsten carbide particles are added to the stainless steel wear-resistant alloy of the outer wear-resistant layer, the volume ratio of the tungsten carbide particles is 10%, and the tungsten carbide particles are evenly distributed in the wear-resistant layer.

[0027] The beneficial effects of this technical solution are:

[0028] (1) The multi-layer composite stainless steel wire of the present invention combines the high strength of the central core material, the good bonding performance of the intermediate transition layer, and the high wear resistance of the outer wear-resistant layer through a unique three-layer structural design. This allows the stainless steel wire to have a tensile strength of not less than 1200 MPa, capable of withstanding loads in high-stress environments, and excellent corrosion resistance (thanks to the alloy composition of the 304 stainless steel core material and the intermediate transition layer). It also has good wear resistance (the outer wear-resistant layer has a hardness of 600 HV and contains uniformly distributed tungsten carbide particles). This can meet the stringent requirements for the comprehensive performance of stainless steel wire in high-precision fields such as aerospace, marine engineering, and automotive engines, effectively solving the problem that existing stainless steel wire cannot simultaneously meet multiple high-performance requirements.

[0029] (2) The intermediate transition layer and the central core material are firmly bonded through a precisely controlled thermal diffusion process, with a bonding strength of no less than 300 MPa. A dense bonding interface is formed between the outer wear-resistant layer and the intermediate transition layer through a precise magnetron sputtering deposition process, and the element diffusion depth at the bonding interface is 0.05 mm. This high-strength, dense interlayer bonding structure effectively prevents the delamination of each layer during processing and use. Whether under the tensile force during the wire drawing process or under the complex external forces of bending, torsion, and friction in actual use, the integrity and stability of the structure can be maintained, which greatly improves the reliability and service life of the product, reduces the safety hazards and maintenance costs caused by structural failure, and solves the problem of unstable bonding between the layers of composite structure stainless steel wire.

[0030] (3) Each link in the entire preparation method, from the preparation process parameters of the central core material (such as heating temperature, holding time, drawing compression ratio, work hardening rate, annealing conditions), to the coating and thermal diffusion process parameters of the intermediate transition layer (gas flow rate, powder feeding amount, spraying distance, thermal diffusion temperature, time, rate), to the deposition process parameters of the outer wear-resistant layer (deposition rate, temperature, pressure, tungsten carbide particle processing parameters) and the final heat treatment conditions (temperature, time, heating rate, cooling method), have been precisely controlled and optimized, so that the various properties of the stainless steel wire (strength, hardness, wear resistance, corrosion resistance, bonding strength) can be precisely adjusted and stably reproduced. This is not only conducive to large-scale standardized production, improving production efficiency and reducing production costs, but also can flexibly adjust process parameters according to the special needs of different customers, customize stainless steel wire products with specific properties, meet diverse market needs, and solve the problems of difficult precise control of stainless steel wire properties and customized production difficulties in the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1A comparison table of material composition and performance parameters of different embodiments of the method for manufacturing a multi-layer composite structure stainless steel wire proposed by the present invention;

[0032] Figure 2 This is a performance comparison table of different embodiments of the method for manufacturing a multi-layer composite structure stainless steel wire proposed in the present invention under simulated working conditions;

[0033] Figure 3 This is a table showing comparative test data on the corrosion resistance of various embodiments of the method for manufacturing a multi-layer composite structure stainless steel wire proposed in the present invention compared with conventional stainless steel wire;

[0034] Figure 4 This is a table showing comparative test data on the high-temperature performance of various embodiments of the method for manufacturing a multi-layer composite structure stainless steel wire proposed in the present invention compared with conventional stainless steel wire;

[0035] Figure 5 This is a table showing comparative test data on fatigue performance of various embodiments of the method for manufacturing a multi-layer composite structure stainless steel wire proposed in the present invention compared with conventional stainless steel wire;

[0036] Figure 6 This is a table showing the low-temperature toughness comparison test data of various embodiments of the method for manufacturing a multi-layer composite structure stainless steel wire proposed in the present invention compared with traditional stainless steel wire;

[0037] Figure 7 This is a table showing the comprehensive comparison test data of the hardness and wear resistance of each embodiment of the manufacturing method of the multi-layer composite structure stainless steel wire proposed in the present invention compared with traditional stainless steel wire. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] The specific implementation process is as follows:

[0040] Example 1:

[0041] See also Figure 1-7 The present invention provides a technical solution: a method for manufacturing a multi-layer composite structure stainless steel wire, comprising the following steps:

[0042] S1: Preparation of the central core material: Select a stainless steel billet that meets the 304 stainless steel standard, heat it to 1100-1200°C, and keep it warm for 2-3 hours to homogenize the billet and eliminate possible composition segregation defects;

[0043] A multi-pass wire drawing process is adopted. After each wire drawing pass, an advanced online tension detection and adjustment device is used to ensure the stability of the wire tension during the drawing process to avoid uneven wire diameter or crack defects caused by tension fluctuations. The initial compression ratio of the wire drawing die is 1.3, and the wire drawing is performed in an increment of 0.1 each time. Multiple drawing passes are performed by gradually decreasing the compression ratio to effectively control the degree of work hardening until the stainless steel billet is processed into a high-strength stainless steel wire with a diameter of 2mm. The work hardening rate is controlled between 30% and 40% during the wire drawing process.

[0044] The drawn stainless steel wire is annealed in an argon protective atmosphere at a temperature of 800-900°C for 2 hours and a cooling rate of 50-80°C / h. Annealing can eliminate the work hardening produced during the drawing process, restore the plasticity of the steel wire, refine the grains, and improve the comprehensive mechanical properties of the steel wire.

[0045] S2: Coating and thermal diffusion of the intermediate transition layer: The alloy powder is accurately prepared according to the alloy composition ratio of the intermediate transition layer, and the intermediate transition layer alloy powder is sprayed on the periphery of the central core material using the supersonic flame spraying process. The gas flow rate during supersonic flame spraying is 15L / min-20L / min, and the powder feeding amount is 30g / min-40g / min. During supersonic flame spraying, hydrogen and oxygen are used as fuel gases, with a hydrogen flow rate of 15L / min-20L / min, an oxygen flow rate of 30L / min-40L / min, a powder feeding amount of 30g / min-40g / min, a spraying distance of 150mm-200mm, and a spray gun moving speed of 300mm / s-500mm / s, so that the spraying thickness reaches 0.5mm;

[0046] The sprayed composite wire is placed in a vacuum thermal diffusion furnace and subjected to thermal diffusion treatment in an environment with a vacuum degree better than 5×10⁻³Pa. The thermal diffusion temperature is 1000℃-1100℃, the thermal diffusion time is 3 hours, the heating rate is 10℃ / min-15℃ / min, and the cooling rate is 8℃ / min-12℃ / min. During the thermal diffusion process, the alloy elements of the intermediate transition layer and the elements of the central core material diffuse with each other to form a strong metallurgical bond, ensuring good bonding strength and cooperative working ability between the two layers, so that the intermediate transition layer and the central core material form a strong bond;

[0047] S3: The outer wear-resistant layer is deposited on the periphery of the intermediate transition layer by magnetron sputtering deposition process. The sputtering target is an alloy target that matches the composition of the outer wear-resistant layer alloy. The sputtering power is 1000W-1500W, the distance between the target and the steel wire is 80mm, the deposition rate is controlled at 10μm / h-15μm / h, the deposition temperature is 400℃-500℃, and the deposition pressure is 2Pa-3Pa;

[0048] During the deposition process, tungsten carbide particles are introduced synchronously through a powder introduction device. Before introduction, the tungsten carbide particles are subjected to ultrasonic dispersion treatment in anhydrous ethanol. The ultrasonic frequency is 20kHz-30kHz and the ultrasonic time is 30min-60min. The treated tungsten carbide particles can be evenly dispersed in the outer wear-resistant layer, thereby effectively improving the wear resistance of the stainless steel wire and finally forming an outer wear-resistant layer with a thickness of 0.3mm.

[0049] S4: The prepared stainless steel wire is subjected to a final heat treatment under a nitrogen protective atmosphere, with a heat treatment temperature of 500°C-600°C, a heat treatment time of 1 hour, a heating rate of 12°C / min-18°C / min, and a furnace cooling method. The final heat treatment can further optimize the organizational structure of the entire composite steel wire, eliminate internal residual stress, and improve its comprehensive performance, making it more stable and reliable in subsequent use, thereby improving the comprehensive performance of the entire steel wire, and finally obtaining the prepared multi-layer composite structure stainless steel wire;

[0050] According to the above manufacturing method, a batch of high-quality 304 stainless steel billets are selected, first heated to 1150℃, kept warm for 2.5 hours, and then subjected to multi-pass drawing. The compression ratio of the wire drawing die in the first pass is 1.4, the second pass is 1.5, the third pass is 1.6... and so on. During the drawing process, the work hardening rate is closely monitored to keep it at about 33%. Finally, a central core stainless steel wire with a diameter of 2 mm is obtained. It is annealed heat treated at 850℃, the annealing temperature is set to 850℃, the annealing time is 2 hours, and the cooling rate is controlled at 60℃ / h. Then, an intermediate transition layer alloy powder is prepared, in which the chromium content is 20%, nickel is 10%, molybdenum is 3%, manganese is 2%, silicon is 1%, copper is 0.5%, niobium is 0.1%, vanadium is 0.05%, and titanium is 1%. The supersonic flame spraying process is adopted, the hydrogen flow rate is 18L / min, the oxygen flow rate is 35L / min, the powder feeding amount is 35g / min, the spraying distance is 180mm, and the spray gun is moved The moving speed is 400mm / s, and a 0.5mm thick intermediate transition layer is sprayed on the periphery of the central core material. Then the composite wire is placed in a vacuum thermal diffusion furnace. In an environment with a vacuum degree of 3×10⁻³Pa, the temperature is increased to 1050℃ at a heating rate of 12℃ / min. Thermal diffusion is carried out for 3 hours, and then the temperature is cooled at a cooling rate of 10℃ / min. Then, a magnetron sputtering deposition process is adopted with a sputtering power of 1200W, a distance between the target and the steel wire of 80mm, and a deposition rate of 12μm / h. The deposition temperature was 450°C and the deposition pressure was 2.5 Pa. An outer wear-resistant layer alloy was deposited on the periphery of the intermediate transition layer, and tungsten carbide particles that had been ultrasonically dispersed (ultrasonic frequency 25 kHz, ultrasonic time 45 min) were simultaneously introduced to form an outer wear-resistant layer with a thickness of 0.3 mm. Finally, the prepared multi-layer composite structure stainless steel wire was subjected to a final heat treatment under nitrogen protection at a temperature of 550°C, a heat treatment time of 1 hour, a heating rate of 15°C / min, and then cooled with the furnace.

[0051] Table 1 details the key process parameters and corresponding test data for each manufacturing step in Example 1, from core material preparation to final heat treatment. During the core material heating step, the specific heating temperature of 1150°C and holding time of 2.5 hours are designed to homogenize the blank, laying a good foundation for the subsequent wire drawing process. During the wire drawing process, precisely controlled multi-pass compression ratios and work hardening rates ensure that the core material maintains the desired strength and ductility while achieving the target diameter of 2 mm. The parameter settings of the annealing process (temperature 850℃, time 2 hours, cooling rate 60℃ / h) are aimed at eliminating the work hardening caused by wire drawing and refining the grains. From the test data "significant grain refinement effect and good plasticity recovery", it can be seen that the process has achieved the expected effect. In the intermediate transition layer spraying process, the determination of various parameters (hydrogen flow rate, oxygen flow rate, powder feeding amount) is to form a transition layer with uniform thickness (0.5mm) and good quality on the periphery of the central core material. The vacuum degree, heating and cooling rate, and processing temperature and time parameters of the thermal diffusion process ensure the formation of a strong bonding interface between the intermediate transition layer and the central core material, uniform element diffusion, and the deposition process of the outer wear-resistant layer. In the process, the sputtering power, deposition rate, temperature, pressure and ultrasonic treatment parameters of tungsten carbide particles work together to make the thickness of the outer wear-resistant layer reach 0.3mm and the tungsten carbide particles evenly distributed. The parameters of the final heat treatment further optimize the overall structure, eliminate residual stress, and improve the overall performance. The test data shows that the tensile strength of the central core material of the multi-layer composite structure stainless steel wire is 1250MPa, the bonding strength between the middle transition layer and the central core material is 320MPa, and the hardness of the outer wear-resistant layer is 610HV. It shows excellent performance under simulated high wear and high stress conditions. The wear amount is reduced by about 60% compared with traditional stainless steel wire, and the tensile strength is increased by about 30%.

[0052]

[0053] Table 1 Key process parameters and test data of a manufacturing process of embodiment 1

[0054] Example 2:

[0055] See also Figure 1-7 The present invention provides a technical solution: according to steps S1-S4 of Example 1, a 304 stainless steel billet similar to that in Example 1 is selected, heated to 1100°C, and held at that temperature for 3 hours before drawing; the compression ratios of the drawing die are set to 1.3, 1.45, and 1.6, respectively, and the work hardening rate is controlled at about 35% to obtain a central core steel wire with a diameter of 2 mm; the annealing heat treatment temperature is 820°C, and the cooling rate is 70°C / h;

[0056] The intermediate transition layer alloy powder contains 19% chromium, 9% nickel, 2.5% molybdenum, 1.8% manganese, 0.8% silicon, 0.4% copper, 0.08% niobium, 0.04% vanadium, and 0.8% titanium. During supersonic flame spraying, the hydrogen flow rate is 16 L / min, the oxygen flow rate is 32 L / min, the powder feed rate is 32 g / min, the spraying distance is 160 mm, the spray gun movement speed is 350 mm / s, and the vacuum degree during vacuum thermal diffusion treatment is 4×10⁻³Pa, the heating rate is 11°C / min to 1020°C, and the cooling rate is 9°C / min after 3 hours of thermal diffusion.

[0057] The outer wear-resistant layer was deposited by magnetron sputtering at a sputtering power of 1100 W, a deposition rate of 11 μm / h, a deposition temperature of 420°C, and a deposition pressure of 2.2 Pa. Ultrasonic dispersion (ultrasonic frequency of 22 kHz, ultrasonic time of 35 min) of tungsten carbide particles was introduced. The final heat treatment temperature was 520°C, and the heating rate was 13°C / min.

[0058] Table 2 shows the process parameters and test results of each step in the manufacturing process for Example 2. The central core material heating temperature (1100°C) and holding time (3 hours) are slightly different from those in Example 1, which affects the initial microstructure of the blank. In the subsequent wire drawing process, different compression ratios (1.3 for the first pass and 1.45 for the second pass) and work hardening rates (35%) are controlled to obtain a central core material steel wire with a diameter of 2 mm. The annealing process parameters (temperature 820°C, cooling rate 70°C / h) are also adjusted accordingly. The test data show that the uniformity of the microstructure and plastic recovery are better. The intermediate transition layer spraying and thermal expansion are better. Changes in the parameters of the dispersion process, such as hydrogen flow rate of 16L / min and oxygen flow rate of 32L / min, lead to differences in the final bonding interface and element diffusion. The test data can be used to analyze the influence of these parameters on the quality of the transition layer. The parameters of the outer wear-resistant layer deposition and the final heat treatment also have their own characteristics, which ultimately makes the stainless steel wire of this embodiment show different characteristics from those of Example 1 in performance. The central core material of the stainless steel wire has a tensile strength of 1220MPa, a bonding strength of 310MPa, and a hardness of the outer wear-resistant layer of 605HV. In actual tests, the wear amount is reduced by about 55% compared with traditional stainless steel wire, and the tensile strength is increased by about 25%.

[0059]

[0060] Table 2 Key process parameters and test data of the manufacturing process in Example 2

[0061] Embodiment three:

[0062] See also Figure 1-7The present invention provides a technical solution: according to steps S1-S4 in Example 1, the same 304 stainless steel blank as in Example 1 is selected as the starting material, heated to 1200°C and kept warm for 2 hours, and then drawn, the drawing compression ratio is set to a series of values ​​of 1.5, 1.6, and 1.7, the work hardening rate is controlled at 30%-32%, and a center core steel wire with a diameter of 2 mm is produced. The annealing temperature is 880°C, the cooling rate is 55°C / h, and the intermediate transition layer alloy composition is: 21% chromium, 11% nickel, 3.5% molybdenum, 2.2% manganese, 1.2% silicon, 0.6% copper, 0.12% niobium, 0.06% vanadium, and 1.2% titanium. The supersonic flame spraying parameters are: The hydrogen flow rate was 19 L / min, the oxygen flow rate was 38 L / min, the powder feeding amount was 38 g / min, the spraying distance was 190 mm, and the spray gun moving speed was 450 mm / s. The vacuum thermal diffusion conditions were a vacuum degree of 2×10⁻³Pa, a temperature increase of 14°C / min to 1080°C, a temperature decrease of 11°C / min after 3 hours of thermal diffusion, and magnetron sputtering deposition of the outer wear-resistant layer. The sputtering power was 1400 W, the deposition rate was 14 μm / h, the deposition temperature was 480°C, the deposition pressure was 2.8 Pa, and the tungsten carbide particles were ultrasonically dispersed (ultrasonic frequency 28 kHz, ultrasonic time 50 min). The final heat treatment temperature was 580°C and the heating rate was 17°C / min.

[0063] Table 3 presents the manufacturing process parameters and test data details for Example 3. The central core material heating process employed a higher temperature of 1200°C and a holding time of 2 hours, slightly different from Examples 1 and 2. This significantly impacted the homogenization of the billet. During the wire drawing process, specific compression ratios (1.5, 1.6, and 1.7) and work hardening rates (30-32%) were employed to achieve the desired central core material. Annealing (temperature 880°C, cooling rate 55°C / h) further optimized its microstructure. The intermediate transition layer spraying parameters (hydrogen flow rate 19 L / min) and thermal diffusion parameters (vacuum level 2 × 10⁻³ Pa) ensured a close bond between the transition layer and the central core material, ensuring good element diffusion. The deposition parameters of the outer wear-resistant layer (sputtering power 1400W) ensure the high-quality formation of the wear-resistant layer, and the final heat treatment parameters (temperature 580°C) improve the overall performance. The test data show the results of the synergistic effect of various process links, such as the excellent performance indicators of the central core material tensile strength of 1280MPa and the bonding strength of 330MPa.

[0064]

[0065] Table 3 Key process parameters and test data of the manufacturing process of Example 3

[0066] Example 4:

[0067] See also Figure 1-7The present invention provides a technical solution: a manufacturing method of a multi-layer composite structure stainless steel wire, comprising a central core material, an intermediate transition layer and an outer wear-resistant layer, wherein the central core material is a high-strength stainless steel wire, the stainless steel material of the central core material is 304 stainless steel, the tensile strength of which is not less than 1200 MPa, the diameter of which is 2 mm, and the central core material serves as the core support part of the entire composite steel wire and bears the main tensile load. The intermediate transition layer is wrapped around the outer periphery of the central core material, the intermediate transition layer is a stainless steel alloy layer with a specific alloy composition, the thickness of which is 0.5 mm, and the alloy composition ratio in the intermediate transition layer is: chromium 18%-22%, nickel 8%-12%, molybdenum 2%-4%, manganese 1.5%-2.5%, silicon 0.5%-1.5%, copper 0.3%-0.8% and a trace amount of niobium 0.05%-0.15% and vanadium 0.03%-0.08%, the balance being Fe and unavoidable impurities, and the intermediate transition layer and the central core material are bonded by thermal diffusion, and the bonding strength is not less than 3 00MPa, the stainless steel alloy composition of the intermediate transition layer also includes titanium 0.5%-1.5%, and the titanium element forms a titanium-rich diffusion layer at the interface between the intermediate transition layer and the central core material, and the thickness of the titanium-rich diffusion layer is 0.02mm. The chromium element can improve the corrosion resistance of stainless steel, nickel can enhance its toughness and corrosion resistance, molybdenum helps to improve strength and corrosion resistance, manganese and silicon elements can improve the processing performance of the alloy, and trace amounts of niobium and vanadium can refine the grains, further improving the comprehensive performance of the material. The intermediate transition layer and the central core material are bonded by thermal diffusion, and the bonding strength is not less than 300MPa. This bonding method can effectively transfer stress, so that the two layers work together to avoid delamination defects. In addition, the stainless steel alloy composition of the intermediate transition layer also includes titanium 0.5%-1.5%, and the titanium element forms a titanium-rich diffusion layer at the interface between the intermediate transition layer and the central core material, and the thickness of the titanium-rich diffusion layer is 0.02mm. The titanium-rich layer can further improve the stability and bonding strength of the bonding interface;

[0068] The outer wear-resistant layer is coated on the periphery of the intermediate transition layer. The outer wear-resistant layer is a stainless steel wear-resistant alloy layer that has undergone special heat treatment. Its thickness is 0.3mm and its hardness is 600HV. The outer wear-resistant layer and the intermediate transition layer are combined through a physical vapor deposition process to form a dense bonding interface. The element diffusion depth at the bonding interface is 0.05mm. This tight bonding ensures that the outer wear-resistant layer will not fall off during use. Tungsten carbide particles are added to the stainless steel wear-resistant alloy of the outer wear-resistant layer. The volume ratio of tungsten carbide particles is 10%, and the tungsten carbide particles are evenly distributed in the wear-resistant layer. Tungsten carbide has extremely high hardness and wear resistance, which can significantly improve the wear resistance of stainless steel wire, so that it can still maintain good performance in high wear environments.

[0069] Figure 1The comparison table of material composition and performance parameters of different embodiments mainly presents the key material composition data and important performance parameters of the multi-layer composite structure stainless steel wire in the three embodiments. By comparing the tensile strength of the central core material, the bonding strength of the intermediate transition layer and the hardness of the outer wear-resistant layer of different embodiments, the differences in mechanical properties of the embodiments can be intuitively seen. For example, the tensile strength of the central core material of Example 3 is the highest, reaching 1280MPa. This is due to the combined influence of the heating temperature, wire drawing process parameters and annealing treatment during the preparation of the central core material, which makes the organizational structure of the central core material more optimized. In terms of material composition, the chromium and nickel content of the intermediate transition layer varies in different embodiments. These changes will affect the corrosion resistance, strength and toughness of the transition layer, and thus have a synergistic effect on the performance of the entire composite steel wire. The volume fraction of tungsten carbide in the outer wear-resistant layer remains consistent, indicating that in the design of the present invention, this volume fraction is determined to be a key factor in improving wear resistance. This ratio is maintained under different process conditions to ensure a stable improvement in wear resistance.

[0070] Figure 2 The performance of the stainless steel wires of the three embodiments under simulated actual working conditions was compared in detail. The relative reduction in wear reflects the improvement in wear resistance of the outer wear-resistant layer and the entire composite structure. The wear of Example 3 was reduced by about 65% compared with that of the traditional stainless steel wire, which is the best performance. This is due to its comprehensive advantages in material composition and manufacturing process. The relative increase in tensile strength reflects the enhancement effect of the central core material and the synergistic effect between the layers on the overall strength. The tensile strength of Example 3 was relatively increased by about 35%, indicating that the processing in the preparation of the central core material and the bonding process of the layers enables the layers to play a more effective role when bearing tensile loads, thereby significantly improving the overall tensile strength. In comparison, the performance improvement of Example 2 is slightly lower than that of Examples 1 and 3. This is due to the different performance results caused by the comprehensive differences in their process parameters and material composition, but overall they all exceed the performance of traditional stainless steel wire.

[0071] See also Figure 3 Corrosion resistance comparison test data table

[0072] Salt spray test (time for rust to appear, h):

[0073] 1. Samples of conventional stainless steel wire and multi-layer composite stainless steel wire of the same specifications (length and diameter) were collected separately. The number of samples in each group should be at least 3 to ensure the reliability of the data.

[0074] 2. Use sandpaper to polish the sample surface to the same roughness, then clean it with anhydrous ethanol and dry it to remove surface oil and impurities;

[0075] 3. Prepare a salt spray test chamber, prepare sodium chloride solution according to the standard configuration, set the concentration to 5% (mass fraction), and adjust the temperature in the test chamber to 35°C and the relative humidity to 95%;

[0076] 4. Place the treated samples in different locations in the salt spray test chamber to ensure that the samples do not touch each other and are in an area where the salt spray is evenly distributed;

[0077] 5. Take out the samples every 24 hours and observe the surface of the samples under a microscope to see if there are any rust spots. Record the time when the rust spots appear. For each group of samples, the time when the first rust spot appears is taken as the test result of that group.

[0078] According to the experimental results, the traditional stainless steel wire showed rust spots after 200 hours, indicating that its corrosion resistance was relatively weak in such a harsh environment. However, the multi-layer composite stainless steel wire of Example 1 did not show rust spots until 500 hours, Example 2 after 450 hours, and Example 3 after 600 hours. This is because the rational combination of materials in each layer and the interface bonding characteristics in the multi-layer composite structure effectively prevented the corrosion of the chloride ion corrosive medium. In particular, the alloy elements (such as chromium and nickel) in the intermediate transition layer and the outer wear-resistant layer formed a denser and more stable passivation film on the surface, which delayed the corrosion process.

[0079] Weight loss rate after immersion in acidic solution (%, immersion for 72 hours):

[0080] 1. Accurately weigh the same mass of conventional stainless steel wire and stainless steel wire samples from each embodiment. The shapes can be filamentous or sheet-like. Each group of samples should contain no less than 3 samples.

[0081] 2. Prepare an acidic immersion solution using 5% (volume fraction) sulfuric acid solution. The volume of the solution should be sufficient to completely immerse the sample and place it in a constant temperature water bath and adjust the temperature to 25°C.

[0082] 3. Hang or place the samples in the acid solution, ensuring that the samples are completely immersed and do not touch the container wall;

[0083] 4. After soaking for 72 hours, remove the sample, rinse with plenty of water, then clean with anhydrous ethanol and dry to constant weight;

[0084] 5. Calculate the weight loss rate of each group of samples according to the formula: weight loss rate = [(initial mass - final mass) / initial mass] × 100%, and take the average value as the test result;

[0085] According to the experimental results, when stainless steel wire is immersed in an acidic solution, a chemical reaction occurs, resulting in material mass loss. The weight loss rate of conventional stainless steel wire after 72 hours of immersion is 0.5%, indicating that it suffers from a certain degree of corrosion in an acidic environment. The weight loss rate of Example 1 is only 0.15%, Example 2 is 0.2%, and Example 3 is 0.1%. This is because the various layers of the composite steel wire have better barrier and resistance to acidic media. The special alloy composition of the intermediate transition layer can neutralize the corrosion of acidic substances to a certain extent. The outer wear-resistant layer also plays a protective role, reducing the contact opportunity between the acidic solution and the central core material, thereby reducing the overall weight loss rate and reflecting excellent acid corrosion resistance.

[0086] Weight loss rate after immersion in alkaline solution (%, immersion for 72 hours):

[0087] 1. Similar to the acid solution immersion test, prepare samples of the same quality and specifications, with each group containing no less than 3 samples;

[0088] 2. Prepare an alkaline soaking solution, such as 10% (mass fraction) sodium hydroxide solution, place it in a constant temperature water bath and adjust the temperature to 25°C;

[0089] 3. Soak the sample in an alkaline solution for 72 hours. The procedure is the same as for the acidic solution, including the post-soaking cleaning and drying steps.

[0090] 4. Calculate the weight loss rate of each group of samples in alkaline solution according to the weight loss rate calculation formula, and use the average value as the final test data;

[0091] According to the experimental results, in the alkaline solution immersion test, the weight loss rate of the conventional stainless steel wire was 0.4%; the weight loss rates of the multi-layer composite stainless steel wire of Example 1 were 0.12%, Example 2 was 0.18%, and Example 3 was 0.08%. This shows that the multi-layer composite structure also exhibits good corrosion resistance in an alkaline environment. The synergistic effect between the layers can resist the corrosion of the stainless steel wire by alkaline substances. This may be because certain elements (such as silicon) in the intermediate transition layer and the outer wear-resistant layer form stable compounds in the alkaline environment, which inhibits the corrosion reaction.

[0092] See also Figure 4 High temperature performance comparison test data table

[0093] High temperature tensile strength (600°C, MPa):

[0094] 1. Process and prepare standard tensile specimens. The shape and size of the specimens of conventional stainless steel wire and the stainless steel wire of each embodiment shall be strictly in accordance with the relevant standards (GB / T228.1-2010). Each group of specimens shall be at least 3;

[0095] 2. Preheat the high-temperature tensile testing machine to 600°C and stabilize the temperature to ensure that the temperature fluctuation is within ±5°C during the test;

[0096] 3. Install the specimen on the fixture of the high-temperature tensile testing machine, ensuring that the clamp is secure and the specimen axis is aligned with the direction of tension;

[0097] 4. Apply tension to the specimen at a constant rate of 0.5 mm / min, while recording the force and displacement data until the specimen breaks.

[0098] 5. Calculate the tensile strength of each specimen based on the stress-strain curve and take the average value as the high-temperature tensile strength test result of the group of specimens at 600°C;

[0099] According to experimental results, the mechanical properties of materials change under high temperature conditions (600°C). The high-temperature tensile strength of conventional stainless steel wire is 400 MPa, while the multilayer composite stainless steel wire of Example 1 reaches 650 MPa, Example 2 reaches 600 MPa, and Example 3 reaches 700 MPa. This is due to the interaction of the various layers of material in the multilayer composite structure at high temperatures. The central core material provides a certain basic strength, the alloying elements in the intermediate transition layer can maintain good structural stability at high temperatures, and the strong bond between the intermediate transition layer and the central core material enables effective stress transmission. The outer wear-resistant layer also strengthens the overall structure to a certain extent, and together they improve the ability to withstand tensile loads at high temperatures.

[0100] High temperature oxidation resistance (weight gain rate, mg / cm²・h, 800°C, 100h):

[0101] 1. Prepare conventional stainless steel wire and stainless steel wire samples of the same surface area. The shapes can be sheet or wire. The number of samples in each group should be no less than 3.

[0102] 2. After cleaning and drying the sample, accurately weigh its initial mass;

[0103] 3. Preheat the high-temperature oxidation test furnace to 800°C and maintain a stable temperature within a fluctuation range of ±3°C;

[0104] 4. Place the samples on the ceramic holder in the high-temperature oxidation test furnace, ensuring that the samples do not touch each other and are in a uniform temperature area in the furnace;

[0105] 5. After 100 hours of oxidation, remove the sample, cool it to room temperature in a desiccator, and then accurately weigh its final mass;

[0106] 6. Calculate the weight gain rate of each group of samples according to the formula: weight gain rate = [(final mass - initial mass) / (sample surface area × oxidation time)], and use the average value as the test result;

[0107] High-temperature oxidation resistance measures a material's ability to resist oxidation in a high-temperature, aerobic environment. Experimental results show that after 100 hours at 800°C, the weight gain rate of conventional stainless steel wire is 0.5 mg / cm²·h, indicating a significant oxidation reaction on its surface. The weight gain rates of Example 1 are 0.2 mg / cm²·h, Example 2 is 0.25 mg / cm²·h, and Example 3 is 0.15 mg / cm²·h. This is because the alloying elements in each layer of the multilayer composite structure can form a dense oxide film at high temperatures, preventing further inward diffusion of oxygen, thereby reducing the oxidation rate. Example 3, likely due to its optimized material composition and manufacturing process, performs better in high-temperature oxidation resistance.

[0108] See also Figure 5 Fatigue performance comparison test data table

[0109] Fatigue limit (MPa, 10^7 cycles):

[0110] 1. Process fatigue test samples. The shape and size of the samples of conventional stainless steel wire and the stainless steel wire of each embodiment should comply with the fatigue test standard (ASTM E466). The number of samples in each group should be at least 5;

[0111] 2. Install and debug the fatigue testing machine, set the test frequency to 100 Hz, and the stress ratio R=-1 (symmetrical tension and compression cycle);

[0112] 3. First, estimate a higher stress level, install the sample in the fixture of the fatigue testing machine, and start the test;

[0113] 4. Observe the fatigue failure of the sample during the test and record the number of cycles at failure;

[0114] 5. If failure occurs within 10^7 cycles, reduce the stress level; if failure does not occur, increase the stress level and repeat the test until the maximum stress value at which failure does not occur after 10^7 cycles is found. This is the fatigue limit, and the average value of the test results for each group of samples is taken.

[0115] The fatigue limit is the maximum stress value that a material can withstand under an alternating load and can withstand an unlimited number of cycles without damage. According to experimental results, the fatigue limit of traditional stainless steel wire is 300 MPa, while the fatigue limit of the multilayer composite stainless steel wire of Example 1 is increased to 450 MPa, Example 2 to 420 MPa, and Example 3 to 500 MPa. This is due to the design of the multilayer composite structure. The good combination between the layers makes the stress distribution more uniform under the action of alternating loads, reducing stress concentration. The coordinated work of the central core material, the intermediate transition layer, and the outer wear-resistant layer can better withstand repeated tensile and compressive stresses, thereby significantly improving the fatigue limit.

[0116] Fatigue life (times, under 350MPa stress):

[0117] 1. Prepare samples of the same specifications as those for the fatigue limit test, with each group containing no less than 3 samples;

[0118] 2. Debug the fatigue testing machine, set the stress level to 350 MPa, the frequency to 100 Hz, and the stress ratio R=-1;

[0119] 3. Install the sample on the fatigue testing machine, start the test and begin counting;

[0120] 4. Record the number of cycles for each sample under 350 MPa stress until fatigue failure occurs, and take the average value as the fatigue life test result of the group of samples under this stress;

[0121] According to the experimental results, under a fixed stress of 350 MPa, the fatigue life of the traditional stainless steel wire is 5×10^5 times; the fatigue life of the multilayer composite stainless steel wire of Example 1 reaches 2×10^6 times, Example 2 is 1.8×10^6 times, and Example 3 is 3×10^6 times. This further illustrates the advantage of the multilayer composite structure in improving fatigue performance. The characteristics of the materials of each layer and the interface bonding state can effectively delay the initiation and propagation of fatigue cracks, allowing it to withstand more cyclic loading at the same stress level.

[0122] See also Figure 6 Low temperature toughness comparison test data table

[0123] Impact toughness (-40°C, J / cm²):

[0124] 1. Process and prepare standard impact specimens. The shape and size of the specimens of conventional stainless steel wire and the stainless steel wire of each embodiment shall comply with the impact test standard (GB / T229-2007). Each group of specimens shall be at least 5.

[0125] 2. Adjust the pendulum energy of the impact tester to the appropriate range and set the sample cooling device to -40°C, ensuring that the temperature uniformity is within ±2°C;

[0126] 3. Place the sample in a cooling device and keep it warm for 30 minutes until its temperature reaches -40°C;

[0127] 4. Quickly remove the sample from the cooling device and install it on the support of the impact testing machine, ensuring that the sample is placed correctly and firmly;

[0128] 5. Release the pendulum to impact the specimen, and record the residual energy after the pendulum impacts the specimen. Calculate the impact toughness of each group of specimens according to the formula: impact toughness = (initial energy of the pendulum - residual energy of the pendulum) / cross-sectional area of ​​the specimen notch, and take the average value as the test result.

[0129] Impact toughness reflects a material's ability to withstand impact loads at low temperatures without brittle fracture. Experimental results show that conventional stainless steel wire has an impact toughness of 50 J / cm² at -40°C, while the multilayer composite stainless steel wire of Example 1 has an impact toughness of 80 J / cm², Example 2 has an impact toughness of 75 J / cm², and Example 3 has an impact toughness of 90 J / cm². This is because the combination of alloying elements in the multilayer composite structure and the interaction between the layers maintain good structural integrity at low temperatures, inhibiting the formation of brittle phases. This allows the material to absorb more energy through plastic deformation when subjected to impact, thereby improving impact toughness.

[0130] Low temperature elongation at break (%, -40°C):

[0131] 1. Prepare standard tensile specimens, similar to those for high-temperature tensile strength tests, but consider the special requirements of low-temperature tests. Each group of specimens should be at least three.

[0132] 2. Set the test chamber temperature of the low-temperature tensile testing machine to -40°C and stabilize the temperature within a fluctuation range of ±2°C;

[0133] 3. Install the specimen on the fixture of the low-temperature tensile testing machine, ensuring that the clamp is secure and the specimen axis is aligned with the direction of tension;

[0134] 4. Apply tension to the specimen at a constant rate of 0.5 mm / min, while recording the force and displacement data until the specimen breaks.

[0135] 5. Based on the displacement at fracture and the original gauge length of the specimen, calculate the low-temperature fracture elongation of each group of specimens according to the formula: fracture elongation = [(fracture gauge length - original gauge length) / original gauge length] × 100%, and take the average value as the test result;

[0136] Low-temperature elongation at break indicates the degree of plastic deformation of a material when it breaks at low temperatures. Experimental results show that the elongation at break of conventional stainless steel wire at -40°C is 10%, while that of the multilayer composite stainless steel wire of Example 1 is 18%, that of Example 2 is 15%, and that of Example 3 is 22%. This indicates that the multilayer composite structure has improved plasticity in low-temperature environments. The synergistic deformation ability of each layer of material at low temperatures enables a greater degree of plastic stretching before breaking, avoiding sudden brittle fracture. This is a very important performance improvement for stainless steel wire used in low-temperature conditions.

[0137] See also Figure 7 Hardness and wear resistance comprehensive comparison test data table

[0138] Rockwell hardness (HRC):

[0139] 1. Prepare a smooth sample surface. The surface roughness of the samples of conventional stainless steel wire and the stainless steel wire of each embodiment should comply with the Rockwell hardness test standard (GB / T230.1-2018). Each group of samples should contain at least 3 samples.

[0140] 2. Select a suitable Rockwell hardness tester, install the HRC hardness test indenter, and adjust the hardness tester to zero;

[0141] 3. Place the sample on the workbench of the hardness tester, slowly apply the initial test force (98.07N) to ensure good contact between the indenter and the sample surface, and then adjust the hardness tester pointer to zero;

[0142] 4. Continue to apply the main test force, hold for 4 seconds, then remove the main test force, retain the initial test force, and read the hardness value on the hardness tester dial. Test each sample at least 3 times at different positions, and take the average value as the Rockwell hardness value of the sample. The average value of the results of each group of samples is taken as the final test data;

[0143] Hardness is the ability of a material to resist local plastic deformation. According to experimental results, the Rockwell hardness of conventional stainless steel wire is 25HRC, while the multilayer composite stainless steel wire of Example 1 reaches 40HRC, Example 2 reaches 38HRC, and Example 3 reaches 42HRC. This is mainly due to the extremely high hardness of the tungsten carbide particles added to the outer wear-resistant layer, as well as the good organizational structure and interface bonding formed during the manufacturing process of the entire multilayer composite structure, which significantly improves the overall hardness and can better resist the intrusion and wear of external objects.

[0144] Wear test (wear volume, mm³, 1000 revolutions on a specific wear tester):

[0145] 1. Prepare wear test samples of the same shape and size. The samples of the conventional stainless steel wire and the stainless steel wire of each embodiment can be cylindrical or block-shaped. Each group of samples should contain at least 3 samples.

[0146] 2. Select a pin-on-disc wear tester, install the sample fixture and the grinding material (grinding wheel or ceramic disc of a specific hardness), and set the tester speed to, for example, 200 rpm and the loading force to a constant value of 100 N.

[0147] 3. Accurately measure and record the initial dimensions (diameter and height) of the sample in order to calculate the initial volume;

[0148] 4. Install the sample on the fixture of the wear tester so that it is in good contact with the grinding material;

[0149] 5. Start the wear tester and stop the test after running it for 1000 revolutions;

[0150] 6. Remove the worn sample and accurately measure its size again. Calculate the worn volume based on the volume change before and after wear using the formula: Wear volume = initial volume - volume after wear. The average value of each group of sample results is used as the final test data.

[0151] In the wear resistance test, the wear volume of the traditional stainless steel wire after running 1000 revolutions on a specific wear tester was 20mm³, while the wear volume of the multi-layer composite stainless steel wire of Example 1 was only 5mm³, 8mm³ of Example 2, and 3mm³ of Example 3. This is because the high hardness of the outer wear-resistant layer and the uniform distribution of tungsten carbide particles effectively resist abrasive wear and adhesive wear during the wear process. At the same time, the intermediate transition layer and the central core material provide good support for the outer layer, ensuring the stability of the structure during the wear process, thereby greatly reducing the wear volume and reflecting excellent wear resistance.

[0152] Therefore, based on the above embodiment and compared with the conventional stainless steel wire manufacturing method, there are the following differences and process differences in the preparation of the central core material:

[0153] Heating temperature: The traditional preparation method usually heats the 304 stainless steel billet to 900℃-1000℃, while the present invention heats it to 1100℃-1200℃. The higher heating temperature helps to make the internal structure of the billet more uniform, providing a better foundation for subsequent grain refinement.

[0154] Holding time: The traditional method only holds 1-1.5 hours, but the present invention extends this to 2-3 hours, allowing alloy elements more time to diffuse, which is beneficial to improving the uniformity of the overall performance of the material;

[0155] Wire drawing process: The compression ratio of traditional wire drawing dies is fixed at around 1.2 and the number of passes is small. The initial compression ratio of the present invention is 1.3, and it is gradually increased by 0.1 to perform multiple passes of wire drawing. The traditional work hardening rate is controlled at 20%-25%, while the present invention controls it at 30%-40%. More precise and reasonable wire drawing parameter settings can further refine the grains and improve the core material strength.

[0156] Cooling method: Traditionally, it is natural cooling or simple air cooling. This invention adopts annealing heat treatment under protective atmosphere of argon gas, with annealing temperature at 800℃-900℃ and strict control of cooling rate at 50℃ / h-80℃ / h. This method can effectively eliminate the internal stress caused by work hardening and stabilize the core material performance.

[0157] Therefore, the tensile strength of the core material prepared by the traditional method is usually 500MPa-700MPa. The present invention, through the above-mentioned optimized data control, can make the tensile strength of the core material reach no less than 1200MPa, significantly improving the strength. This provides a strong guarantee for the use of the entire multi-layer composite structure stainless steel wire under high stress conditions, solves the problem of insufficient strength of traditional 304 stainless steel wire, and at the same time makes the internal structure of the core material more uniform and the performance more stable.

[0158] Differences in the coating and thermal diffusion processes of the intermediate transition layer:

[0159] Thermal spraying parameters: Traditionally, ordinary thermal spraying methods such as arc spraying are used, with a hydrogen flow rate of 10L / min-12L / min, an oxygen flow rate of 20L / min-25L / min, a powder feed rate of 20g / min-25g / min, a spraying distance of 100mm-120mm, and a spray gun moving speed of 200mm / s-300mm / s. The present invention adopts supersonic flame spraying, with a hydrogen flow rate of 15L / min-20L / min, an oxygen flow rate of 30L / min-40L / min, a powder feed rate of 30g / min-40g / min, a spraying distance of 150mm-200mm, and a spray gun moving speed of 300mm / s-500mm / s. The parameter settings of the present invention are more accurate and the range is more reasonable, which can ensure that the transition layer alloy powder is evenly and densely coated on the core material surface;

[0160] Thermal diffusion conditions: Traditional thermal diffusion treatment is rough, with a temperature of 800-900°C, a time of 1-2 hours, and unstable heating and cooling rates. The present invention achieves a thermal diffusion temperature of 1000-1100°C, a thermal diffusion time of 3 hours, a heating rate of 10-15°C / min, and a cooling rate of 8-12°C / min in an environment with a vacuum degree better than 5×10⁻³Pa. The precise thermal diffusion conditions facilitate the full diffusion of alloy elements at the interface, forming a strong bond.

[0161] Therefore, under traditional methods, the bonding strength between the transition layer and the core material is generally between 100MPa and 200MPa, which is prone to delamination and affects the stability of the multi-layer structure. The present invention, through optimized data control, ensures that the bonding strength between the intermediate transition layer and the central core material is not less than 300MPa, effectively avoiding delamination, ensuring the stability and reliability of the multi-layer composite structure during processing and use, and extending the service life of the product.

[0162] Differences in the preparation process of the outer wear-resistant layer:

[0163] Deposition process: Traditionally, electroplating or simple coating processes are used. Electroplating has environmental pollution problems and poor coating quality. The deposition rate of the simple coating process is 5μm / h-8μm / h, the deposition temperature is 300℃-350℃, and the deposition pressure is 1Pa-1.5Pa. The present invention adopts a magnetron sputtering deposition process with a deposition rate of 10μm / h-15μm / h, a deposition temperature of 400℃-500℃, and a deposition pressure of 2Pa-3Pa. It can also precisely control various parameters to ensure process stability.

[0164] Wear-resistant particle treatment: When traditional wear-resistant particles are introduced, the distribution is uneven, with a volume ratio of 5%-8% and no effective dispersion treatment. The present invention introduces tungsten carbide particles with a volume ratio of 10% during the deposition process and uses ultrasonic dispersion treatment (ultrasonic frequency of 20kHz-30kHz, ultrasonic time of 30min-60min, and anhydrous ethanol as the dispersion medium) to make the particles evenly dispersed in the outer wear-resistant layer;

[0165] Therefore, the outer wear-resistant layer prepared by the traditional process has uneven thickness and hardness of 400HV-500HV, and has limited wear resistance. The outer wear-resistant layer prepared by the present invention can be precisely controlled to have a thickness of 0.3mm and a hardness of 600HV, which has good wear resistance and greatly increases the service life of the stainless steel wire under high friction conditions. At the same time, it avoids the environmental problems caused by electroplating and improves the overall quality and performance of the product.

[0166] Differences in the final heat treatment process: Traditional methods usually do not have a dedicated final heat treatment step, or simply perform low-temperature tempering, and there is no precise control over temperature, time, and heating rate. The present invention performs the final heat treatment under a nitrogen protective atmosphere, with a heat treatment temperature of 500°C-600°C, a heat treatment time of 1 hour, a heating rate of 12°C / min-18°C / min, and a furnace cooling method, with strict control over all parameters.

[0167] Therefore, traditional methods are difficult to effectively optimize the microstructure of stainless steel wire and eliminate residual stress, resulting in unstable overall performance. The present invention, through a specific final heat treatment, can further optimize the microstructure, eliminate internal residual stress, and improve the stability and uniformity of overall performance, ensuring that the stainless steel wire can stably perform excellent performance under various complex working conditions.

[0168] To sum up, in the preparation process of multi-layer composite structure stainless steel wire, the data of each link of the present invention are accurately and reasonably optimized and adjusted compared with the traditional preparation data, showing significant beneficial effects in many aspects from improving the strength of the central core material, enhancing the bonding strength between layers, improving the performance of the outer wear-resistant layer to the stable optimization of the overall performance. It effectively solves many problems existing in the traditional preparation method in product performance and structural stability, so that the prepared stainless steel wire can better meet the stringent requirements of modern industry for high-performance materials.

[0169] The above is only an embodiment of the present invention, and common knowledge such as the specific technical solutions or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. A method for manufacturing a multi-layer composite structure stainless steel wire, characterized by: It includes central core material, middle transition layer and outer wear-resistant layer; The intermediate transition layer is wrapped around the outer periphery of the central core material. The intermediate transition layer is a stainless steel alloy layer with a thickness of 0.5 mm. The alloy composition ratio of the intermediate transition layer is: chromium 18%-22%, nickel 8%-12%, molybdenum 2%-4%, manganese 1.5%-2.5%, silicon 0.5%-1.5%, copper 0.3%-0.8%, and trace amounts of niobium 0.05%-0.15% and vanadium 0.03%-0.08%, with the balance being Fe and unavoidable impurities. The intermediate transition layer and the central core material are bonded by thermal diffusion, and the bonding strength is not less than 300 MPa. The outer wear-resistant layer is coated on the outer periphery of the intermediate transition layer. The outer wear-resistant layer is a stainless steel wear-resistant alloy layer that has undergone special heat treatment. The thickness is 0.3 mm and the hardness is 600 HV. The outer wear-resistant layer and the intermediate transition layer are bonded by a physical vapor deposition process to form a dense bonding interface, and the element diffusion depth at the bonding interface is 0.05 mm. The manufacturing method of the multi-layer composite structure stainless steel wire is as follows: S1: Preparation of the central core material: Select a stainless steel billet that meets the 304 stainless steel standard, heat it to 1100-1200°C, and keep it warm for 2-3 hours to homogenize the billet; A multi-pass wire drawing process is used, with online tension detection and adjustment after each drawing pass. The initial compression ratio of the drawing die is 1.3, and the wire drawing is performed in increments of 0.1 each time until the stainless steel billet is processed into a high-strength stainless steel wire with a diameter of 2mm. The work hardening rate is controlled between 30% and 40% during the wire drawing process. The drawn stainless steel wire is subjected to annealing heat treatment under a protective atmosphere of argon, the annealing temperature is 800°C-900°C, the annealing time is 2 hours, and the cooling rate is controlled at 50°C / h-80°C / h; S2: Coating and thermal diffusion of the intermediate transition layer: The alloy powder is accurately prepared according to the alloy composition ratio of the intermediate transition layer, and the intermediate transition layer alloy powder is sprayed on the periphery of the central core material using the supersonic flame spraying process. During supersonic flame spraying, hydrogen and oxygen are used as fuel gases, with a hydrogen flow rate of 15L / min-20L / min, an oxygen flow rate of 30L / min-40L / min, a powder feed rate of 30g / min-40g / min, a spraying distance of 150mm-200mm, and a spray gun moving speed of 300mm / s-500mm / s, so that the spraying thickness reaches 0.5mm; The sprayed composite wire is placed in a vacuum thermal diffusion furnace and subjected to thermal diffusion treatment in an environment with a vacuum degree better than 5×10⁻³Pa. The thermal diffusion temperature is 1000℃-1100℃, the thermal diffusion time is 3 hours, the heating rate is 10℃ / min-15℃ / min, and the cooling rate is 8℃ / min-12℃ / min, so that the intermediate transition layer and the central core material form a firm bond; S3: The outer wear-resistant layer is deposited on the periphery of the intermediate transition layer by magnetron sputtering deposition process. The sputtering target material is an alloy target material that matches the composition of the outer wear-resistant layer alloy. The deposition process is controlled at a deposition rate of 10μm / h-15μm / h, a deposition temperature of 400℃-500℃, and a deposition pressure of 2Pa-3Pa. During the deposition process, tungsten carbide particles are introduced synchronously through a powder introduction device. Before introduction, the tungsten carbide particles are subjected to ultrasonic dispersion treatment. The dispersion medium of the tungsten carbide particles is anhydrous ethanol, the ultrasonic frequency is 20kHz-30kHz, and the ultrasonic time is 30min-60min, so that the tungsten carbide particles are evenly dispersed in the outer wear-resistant layer, and finally an outer wear-resistant layer with a thickness of 0.3mm is formed; S4: The prepared stainless steel wire is subjected to final heat treatment under a nitrogen protective atmosphere. The heat treatment temperature is 500°C-600°C, the heat treatment time is 1 hour, the heating rate is 12°C / min-18°C / min, and the cooling adopts a furnace cooling method to improve the overall performance of the entire steel wire. Finally, the prepared multi-layer composite structure stainless steel wire is obtained.

2. The method for manufacturing a multi-layer composite stainless steel wire according to claim 1, characterized in that: In S2, the supersonic flame spraying has a gas flow rate of 15 L / min-20 L / min and a powder feeding rate of 30 g / min-40 g / min.

3. The method for manufacturing a multi-layer composite stainless steel wire according to claim 1, wherein: In S3, the magnetron sputtering deposition has a sputtering power of 1000W-1500W, and the distance between the target and the steel wire is 80mm.

4. The method for manufacturing a multi-layer composite stainless steel wire according to claim 1, wherein: The central core material is a high-strength stainless steel wire with a tensile strength of not less than 1200 MPa and a diameter of 2 mm.

5. The method for manufacturing a multi-layer composite stainless steel wire according to claim 1, wherein: The stainless steel material of the central core material is 304 stainless steel.

6. The method for manufacturing a multi-layer composite stainless steel wire according to claim 1, wherein: The stainless steel alloy composition of the intermediate transition layer also includes 0.5%-1.5% titanium, and the titanium element forms a titanium-rich diffusion layer at the interface between the intermediate transition layer and the central core material. The thickness of the titanium-rich diffusion layer is 0.02 mm.

7. The method for manufacturing a multi-layer composite stainless steel wire according to claim 1, characterized in that: Tungsten carbide particles are added to the stainless steel wear-resistant alloy of the outer wear-resistant layer, the volume ratio of the tungsten carbide particles is 10%, and the tungsten carbide particles are evenly distributed in the wear-resistant layer.

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