Preparation method of molybdenum disulfide coating for steel lead screw

Abstract

The invention discloses a molybdenum disulfide coating preparation method for a steel screw rod, which is characterized in that micron-sized MoS2 powder and copper-based brazing filler metal powder are mixed according to the mass ratio of 3.2%-12.8%, then the mixture is coated on the surface of the steel screw rod, and then induction heating is adopted to melt brazing filler metal to realize brazing coating attachment, so that the molybdenum disulfide coating is formed. The preparation method provided by the invention has the characteristics of high molybdenum disulfide adhesion strength, more uniform adhesion, low surface friction coefficient and good high-temperature wear resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of screw rod manufacturing, and in particular to a method for preparing a molybdenum disulfide coating for a steel screw rod. Background Art

[0002] A lead screw (also known as a screw) is generally used in a screw-nut transmission structure and is a component that realizes the conversion between rotational and linear motion. Large-scale / high-precision multi-wire lead screws are crucial in the manufacturing of high-end equipment, such as CNC machine tools, semiconductor equipment, and aerospace. When the lead screw is in operation and in conjunction with the nut component, it is subject to high friction. The heat generated by friction and other external heat sources can easily cause thermal deformation of the lead screw. Therefore, the requirement for the lead screw's ability to prevent thermal deformation is a core element of high-end equipment quality control. How to treat the lead screw surface and reduce friction loss is a basic means of controlling thermal deformation. The application of lubrication and wear-resistant coatings is one of the most commonly used technical methods for lead screw surface treatment.

[0003] The lubrication and wear-resistant coatings of high-end screws must meet four core requirements: low friction, high wear resistance, long life, and adaptability to a wide range of working conditions. These requirements involve high-temperature stability, wear resistance, environmentally friendly lubricants, coating adhesion, and uniformity. Molybdenum disulfide is a coating material with high lubricity and wear resistance. However, existing conventional molybdenum disulfide coatings are generally applied by thermal spray bonding with resin. This method has the following defects when applied to steel screws: 1) The coating has low adhesion to the surface of the steel-based screw; 2) The coating is easy to fall off, making it difficult to meet the requirements of low volatility and high cleanliness in the medical equipment field; 3) The coating is prone to uneven distribution and cannot evenly cover the complex curved surfaces of the screw thread (such as the root and sidewalls). The thickness deviation is often ≤1μm, and the surface roughness is high, making it difficult to meet the needs of high-end equipment manufacturing. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is: how to provide a method for preparing a molybdenum disulfide coating for steel screw rods with high adhesion strength, more uniform adhesion, low surface friction coefficient, and good high-temperature wear resistance.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for preparing a molybdenum disulfide coating for a steel wire rod is characterized in that micron-sized MoS2 powder and copper-based solder powder are mixed in a mass ratio of 3.2%-12.8% and then coated on the surface of the steel wire rod. Induction heating is then used to melt the solder to achieve solder coating adhesion, thereby forming a molybdenum disulfide coating.

[0006] Specifically, the method comprises the following steps: a. Complete the pretreatment of the steel wire rod substrate to make its surface clean; b. Prepare MoS2 powder and copper-based solder powder, mix them evenly and apply them to the surface of the steel wire rod; c. Use induction heating equipment to induction heat the steel wire rod. During heating, control the surface temperature of the substrate to be higher than the melting point of the brazing material (generally higher than 700℃ and lower than 800℃). After induction heating until the copper-based brazing material is completely melted, keep the temperature for 10-30 seconds, and then naturally cool it to room temperature. d. Smooth the surface of the product.

[0007] This heating method allows the copper-based brazing filler metal to melt quickly while preventing overheating of the base material, which can lead to annealing and compromise the strength of the finished product. Holding the filler metal at this temperature for a period of time after melting promotes wetting and diffusion. Natural air cooling is then used to reduce residual stress.

[0008] Furthermore, in step a, the steel wire rod base material is 45 steel material.

[0009] This can better ensure product quality and coating adhesion.

[0010] Furthermore, in step a, during pretreatment, the steel wire rod substrate is first cleaned with acetone or alcohol, and then the surface of the substrate is sandblasted (Sa2.5 grade).

[0011] In this way, cleaning with acetone or alcohol can better remove oil stains and avoid the influence of oil stains on the subsequent brazing coating adhesion. Then sandblasting can better remove the oxide layer, enhance the surface roughness, and better improve the adhesion strength of the coating and the substrate.

[0012] Furthermore, in step a, during the pretreatment of the steel wire rod substrate, after cleaning and sandblasting, a nickel layer with a thickness of 2-5 μm is first formed on the surface of the substrate by electroplating or chemical plating.

[0013] This is because the presence of nickel can have better wettability with the main component Cu in the solder, making it more tightly bonded when cooled and attached after high-temperature melting, thereby improving the wettability of the solder spreading on the substrate surface and the bonding strength with the substrate.

[0014] Furthermore, in step b, the particle size of the micron-sized MoS2 powder is in the range of 1-10 μm, which can better ensure that a coating surface with a lower friction coefficient is obtained.

[0015] Furthermore, in step b, the MoS2 powder is prepared by ball milling into granules and then dispersed by ultrasonic dispersion process.

[0016] This can better avoid MoS2 agglomeration and cause local lubrication failure of the coating.

[0017] Furthermore, in step b, when the MoS2 powder and the copper-based solder powder are mixed, an appropriate amount of starch is added as a binder, and then water is added and stirred evenly to form a spreadable fluid, which is then evenly sprayed onto the surface of the steel wire rod with a spraying thickness of 10-100um.

[0018] In this way, spraying can achieve uniform adhesion of the mixed powder material and ensure the coating quality after subsequent forming. A small amount of starch is added as a binder during mixing, in an amount sufficient to ensure good adhesion of the mixed fluid to the substrate surface during spraying (the specific ratio can be determined through experimentation). This can further enhance the adhesion of the solder and MoS2 powder. Furthermore, during subsequent high-temperature treatment, the starch material will largely decompose into carbon dioxide and water, which evaporates, leaving only a small amount of carbon, which does not affect the quality of the final product.

[0019] Furthermore, in step c, the induction heating equipment uses a medium frequency of 10-50 kHz for induction heating.

[0020] This way, a better balance between heating depth and efficiency can be achieved.

[0021] Furthermore, in step c, an infrared thermometer is used for real-time monitoring during heating to prevent the substrate from overheating.

[0022] Furthermore, in step c, the heating, heat preservation and cooling processes are all protected by argon gas, which can better prevent MoS2 from oxidizing and affecting its quality.

[0023] Furthermore, in the step d, a layer of impregnated resin-based MoS2 composite coating is provided on the surface of the brazing coating of the cooled product by means of impregnated resin composite.

[0024] This is because the molybdenum disulfide coating obtained directly by brazing and induction heating has very high bonding strength with the substrate, but the surface roughness of the brazing and induction heating coating is relatively large, which can cause burrs and other phenomena that affect quality. Furthermore, if the coating is set thicker with this method, it is prone to uneven thickness, resulting in a thinner coating thickness. While the surface smoothness of a resin-impregnated MoS2 coating is relatively high, if it is directly applied to the screw substrate, it suffers from the disadvantage of low bonding strength with the substrate. Therefore, in this application, after applying a layer of molybdenum disulfide coating by induction heating brazing, a layer of impregnated resin-based MoS2 coating is then laminated (the specific lamination process is prior art and will not be described in detail here). The high surface roughness of the brazing and induction coating and its uniform molybdenum disulfide material are utilized to greatly improve the bonding strength between the composite layers. This method overcomes the shortcomings of both coating methods while retaining their respective advantages. This results in a molybdenum disulfide coating with both high bonding strength with the substrate and good surface smoothness, a lower coefficient of friction, and increased coating thickness, further enhancing the surface treatment effect on the substrate. Of course, in specific implementation, step d can also use conventional polishing or grinding to remove oxide scale or burrs on the coating surface, which is also an optional way to achieve surface smoothing.

[0025] Furthermore, the copper-based solder has a material composition ratio by mass of 70-75 parts of copper (Cu), 15-20 parts of tin (Sn), 0.5-1.5 parts of titanium (Ti), 1-2 parts of nickel (Ni), and 0.1-0.3 parts of chromium (Cr).

[0026] Copper, as the base material, has the highest content, providing excellent thermal conductivity, electrical conductivity, and plasticity. Meanwhile, 15-20 parts by weight of tin in the material significantly lowers the melting point of the solder and improves its fluidity after melting. 0.5-1.5 parts by weight of titanium, a highly active element, reduces the formation of high-melting-point phases (NiTi / Cu4Ti). Furthermore, 0.5-1.5 parts by weight of titanium controls the thickness of the interfacial reaction layer to 1-3 μm (this ensures surface hardness and deformation resistance). 1-2 parts by weight of nickel significantly improves the high-temperature strength and oxidation resistance of the solder, inhibiting intergranular corrosion of the Cu-Sn alloy. 0.1-0.3 parts by weight of chromium significantly enhances oxidation resistance, forming a Cr2O3 protective film with the base material, reducing oxidation losses during high-temperature service. Cr and Ni work synergistically to form a dense Cr2O3-NiO composite oxide film, reducing the high-temperature oxidation rate. Therefore, the copper-based solder with the above-mentioned ratio can well complete the setting of the molybdenum disulfide coating. It uses low-temperature copper-tin alloy to wrap molybdenum disulfide, making it difficult for molybdenum disulfide to oxidize under high-temperature conditions. After high-frequency heating and cooling, it ensures that the molybdenum disulfide still maintains good wettability after film formation.

[0027] Furthermore, the copper-based solder is prepared by the following preparation method: 1) Obtaining the material components of the mass ratio for use; 2) Each material is loaded into the melting furnace in order for melting. First, add Cu, Ni, Cr, and Ti. After melting at 1500℃ and cooling to 1150℃, add Zn and Sn. 3) Complete the smelting according to the following requirements: the smelting temperature is required to be 1150-1500℃ (it must be higher than the Cu-Sn eutectic point and ensure that Ni is completely melted); the smelting atmosphere is required to be vacuum (≤10 -2 Pa) or high-purity argon (flow rate 10-15 L / min) atmosphere; stirring requirement is stirring speed 200-300 rpm, continuous 10-15 minutes (electromagnetic stirring or mechanical stirring can be used); 4) Pour the smelted alloy melt into a water-cooled copper mold for rapid initial cooling at a cooling rate of ≥100°C / s (to better reduce component segregation), and cool the melt to 800°C; 5) The initially cooled alloy melt is pumped into an atomizing nozzle for spraying and forming into a spherical powder with a particle size of 20-75 μm under argon protection; 6) The spherical powder obtained by atomization is ball-milled using an ethanol medium with a ball-to-powder ratio of 5:1 to obtain a copper-based solder with a particle size of 1-10 μm.

[0028] Therefore, the above-mentioned preparation method, in which the various materials are melted, atomized, and granulated, followed by ball milling, can quickly produce copper-based brazing filler metal particles of the desired size while ensuring uniform mixing of the various components within the filler metal. The batch addition method employed in this preparation process can better avoid segregation caused by density differences in the materials. After smelting, the metal is rapidly cooled to a sprayable temperature using a water-cooled copper mold, which inhibits the precipitation of brittle phases (such as Cu-Ti and Cu-Cr intermetallic compounds) during spray forming and improves the material's plasticity.

[0029] Furthermore, in step 1), bulk Cu and Sn materials with a purity of ≥99.9% are used, pickled (10% HCl) to remove the oxide film, dried and crushed into small pieces for later use; powdered Ti, Ni and Cr with a purity of ≥99.5% are used, wherein Ti and Cr are vacuum dried (200°C × 2h) and then used.

[0030] In this way, product purity can be better guaranteed.

[0031] Furthermore, in step 2), the melting furnace is a vacuum induction melting furnace (recommended) or an argon-protected medium frequency furnace.

[0032] Furthermore, in step 2), part of the copper material is made into copper foil, and the copper foil is used to wrap Ti and Cr on the upper layer. In this way, oxidation and scattering of Ti and Cr can be better prevented.

[0033] Furthermore, in step 3), a trace amount of rare earth La or Ce in a proportion of 0.1-0.5 parts by mass is added during smelting to better purify the melt and reduce oxide inclusions.

[0034] In summary, the preparation method of the present invention has the advantages of high adhesion strength of molybdenum disulfide, more uniform adhesion, low surface friction coefficient, and good high-temperature wear resistance. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below in conjunction with the preferred embodiment.

[0036] Optimal embodiment: A method for preparing a molybdenum disulfide coating for a steel wire rod, characterized in that micron-sized MoS2 powder and copper-based brazing filler metal powder are mixed in a mass ratio of 3.2%-12.8% and then coated on the surface of the steel wire rod. Induction heating is then used to melt the brazing filler metal to achieve brazing coating adhesion, thereby forming a molybdenum disulfide coating.

[0037] Specifically, the method comprises the following steps: a. Complete the pretreatment of the steel wire rod substrate to make its surface clean; b. Prepare MoS2 powder and copper-based solder powder, mix them evenly and apply them to the surface of the steel wire rod; c. Use induction heating equipment to induction heat the steel wire rod. During heating, control the surface temperature of the substrate to be higher than the melting point of the brazing material (generally higher than 700℃ and lower than 800℃). After induction heating until the copper-based brazing material is completely melted, keep the temperature for 10-30 seconds, and then naturally cool it to room temperature. d. Smooth the surface of the product.

[0038] This heating method allows the copper-based brazing filler metal to melt quickly while preventing overheating of the base material, which can lead to annealing and compromise the strength of the finished product. Holding the filler metal at this temperature for a period of time after melting promotes wetting and diffusion. Natural air cooling is then used to reduce residual stress.

[0039] During implementation, in step a, the steel wire rod base material is 45# steel material.

[0040] This can better ensure product quality and coating adhesion.

[0041] In step a, during the pretreatment of the steel wire rod substrate, acetone or alcohol is first used to clean it, and then the surface of the substrate is sandblasted (Sa2.5 grade).

[0042] In this way, cleaning with acetone or alcohol can better remove oil stains and avoid the influence of oil stains on the subsequent brazing coating adhesion. Then sandblasting can better remove the oxide layer, enhance the surface roughness, and better improve the adhesion strength of the coating and the substrate.

[0043] In step a, during the pretreatment of the steel wire rod substrate, after cleaning and sandblasting, a nickel layer with a thickness of 2-5 μm is first formed on the surface of the substrate by electroplating or chemical plating.

[0044] This is because the presence of nickel can have better wettability with the main component Cu in the solder, making it more tightly bonded when cooled and attached after high-temperature melting, thereby improving the wettability of the solder spreading on the substrate surface and the bonding strength with the substrate.

[0045] During implementation, in step b, the particle size of the micron-sized MoS2 powder is in the range of 1-10 μm, which can better ensure that a coating surface with a lower friction coefficient is obtained.

[0046] In step b, the MoS2 powder is prepared by ball milling into granular form and then dispersed by ultrasonic dispersion process.

[0047] This can better avoid MoS2 agglomeration and cause local lubrication failure of the coating.

[0048] In step b, when MoS2 powder and copper-based solder powder are mixed, an appropriate amount of starch is added as a binder, and then water is added and stirred evenly to form a spreadable fluid, which is then evenly sprayed onto the surface of the steel wire rod with a spraying thickness of 10-100um.

[0049] In this way, spraying can achieve uniform adhesion of the mixed powder material and ensure the coating quality after subsequent forming. A small amount of starch is added as a binder during mixing, in an amount sufficient to ensure good adhesion of the mixed fluid to the substrate surface during spraying (the specific ratio can be determined through experimentation). This can further enhance the adhesion of the solder and MoS2 powder. Furthermore, during subsequent high-temperature treatment, the starch material will largely decompose into carbon dioxide and water, which evaporates, leaving only a small amount of carbon, which does not affect the quality of the final product.

[0050] During implementation, in step c, the induction heating equipment uses a medium frequency of 10-50 kHz for induction heating.

[0051] This way, a better balance between heating depth and efficiency can be achieved.

[0052] In step c, an infrared thermometer is used for real-time monitoring during heating to prevent the substrate from overheating.

[0053] In step c, argon is used as a protective gas during the heating, insulation and cooling processes to better prevent MoS2 from oxidizing and affecting its quality.

[0054] As a better implementation method, in the step d, a layer of impregnated resin-based MoS2 composite coating is provided on the surface of the brazing coating of the cooled product by impregnating resin composite.

[0055] This is because the molybdenum disulfide coating obtained directly by brazing and induction heating has very high bonding strength with the substrate, but the surface roughness of the brazing and induction heating coating is relatively large, which can cause burrs and other phenomena that affect quality. Furthermore, if the coating is set thicker with this method, it is prone to uneven thickness, resulting in a thinner coating thickness. While the surface smoothness of a resin-impregnated MoS2 coating is relatively high, if it is directly applied to the screw substrate, it suffers from the disadvantage of low bonding strength with the substrate. Therefore, in this application, after applying a layer of molybdenum disulfide coating by induction heating brazing, a layer of impregnated resin-based MoS2 coating is then laminated (the specific lamination process is prior art and will not be described in detail here). The high surface roughness of the brazing and induction coating and its uniform molybdenum disulfide material are utilized to greatly improve the bonding strength between the composite layers. This method overcomes the shortcomings of both coating methods while retaining their respective advantages. This results in a molybdenum disulfide coating with both high bonding strength with the substrate and good surface smoothness, a lower coefficient of friction, and increased coating thickness, further enhancing the surface treatment effect on the substrate. Of course, in specific implementation, step d can also use conventional polishing or grinding to remove oxide scale or burrs on the coating surface, which is also an optional way to achieve surface smoothing.

[0056] In this embodiment, the copper-based solder has a material composition ratio by mass of 70-75 parts copper (Cu), 15-20 parts tin (Sn), 0.5-1.5 parts titanium (Ti), 1-2 parts nickel (Ni), and 0.1-0.3 parts chromium (Cr).

[0057] Copper, as the base material, has the highest content, providing excellent thermal conductivity, electrical conductivity, and plasticity. Meanwhile, 15-20 parts by weight of tin in the material significantly lowers the melting point of the solder and improves its fluidity after melting. 0.5-1.5 parts by weight of titanium, a highly active element, reduces the formation of high-melting-point phases (NiTi / Cu4Ti). Furthermore, 0.5-1.5 parts by weight of titanium controls the thickness of the interfacial reaction layer to 1-3 μm (this ensures surface hardness and deformation resistance). 1-2 parts by weight of nickel significantly improves the high-temperature strength and oxidation resistance of the solder, inhibiting intergranular corrosion of the Cu-Sn alloy. 0.1-0.3 parts by weight of chromium significantly enhances oxidation resistance, forming a Cr2O3 protective film with the base material, reducing oxidation losses during high-temperature service. Cr and Ni work synergistically to form a dense Cr2O3-NiO composite oxide film, reducing the high-temperature oxidation rate. Therefore, the copper-based solder with the above-mentioned ratio can well complete the setting of the molybdenum disulfide coating. It uses low-temperature copper-tin alloy to wrap molybdenum disulfide, making it difficult for molybdenum disulfide to oxidize under high-temperature conditions. After high-frequency heating and cooling, it ensures that the molybdenum disulfide still maintains good wettability after film formation.

[0058] Specifically, the copper-based solder is prepared by the following preparation method: 1) Obtaining the material components of the mass ratio for use; 2) Each material is loaded into the melting furnace in order for melting. First, add Cu, Ni, Cr, and Ti. After melting at 1500℃ and cooling to 1150℃, add Zn and Sn. 3) Complete the smelting according to the following requirements: the smelting temperature is required to be 1150-1500℃ (it must be higher than the Cu-Sn eutectic point and ensure that Ni is completely melted); the smelting atmosphere is required to be vacuum (≤10 -2 Pa) or high-purity argon (flow rate 10-15 L / min) atmosphere; stirring requirement is stirring speed 200-300 rpm, continuous 10-15 minutes (electromagnetic stirring or mechanical stirring can be used); 4) Pour the smelted alloy melt into a water-cooled copper mold for rapid initial cooling at a cooling rate of ≥100°C / s (to better reduce component segregation), and cool the melt to 800°C; 5) The initially cooled alloy melt is pumped into an atomizing nozzle for spraying and forming into a spherical powder with a particle size of 20-75 μm under argon protection; 6) The spherical powder obtained by atomization is ball-milled using an ethanol medium with a ball-to-powder ratio of 5:1 to obtain a copper-based solder with a particle size of 1-10 μm.

[0059] Therefore, the above-mentioned preparation method, in which the various materials are melted, atomized, and granulated, followed by ball milling, can quickly produce copper-based brazing filler metal particles of the desired size while ensuring uniform mixing of the various components within the filler metal. The batch addition method employed in this preparation process can better avoid segregation caused by density differences in the materials. After smelting, the metal is rapidly cooled to a sprayable temperature using a water-cooled copper mold, which inhibits the precipitation of brittle phases (such as Cu-Ti and Cu-Cr intermetallic compounds) during spray forming and improves the material's plasticity.

[0060] In the step 1), block-shaped Cu and Sn materials with a purity of ≥99.9% are used, pickled (10% HCl) to remove the oxide film, dried and crushed into small pieces for later use; powdered Ti, Ni and Cr with a purity of ≥99.5% are used, wherein Ti and Cr are vacuum dried (200°C × 2h) and then set aside.

[0061] In this way, product purity can be better guaranteed.

[0062] Step 2) The melting furnace uses a vacuum induction melting furnace (recommended) or an argon-protected medium frequency furnace.

[0063] In step 2), copper foil is made from a portion of the copper material, and the copper foil is used to wrap the Ti and Cr layers on top. This can better prevent the Ti and Cr from oxidizing and scattering.

[0064] In step 3), a trace amount of rare earth La or Ce in a proportion of 0.1-0.5 parts by mass is added during smelting. This can better purify the melt and reduce oxide inclusions.

[0065] Therefore, the preparation method of the present invention has the advantages of high adhesion strength of molybdenum disulfide, more uniform adhesion, low surface friction coefficient, and good high-temperature wear resistance.

[0066] To further validate the effectiveness of the present invention, the applicant further conducted quality testing and evaluation of the molybdenum disulfide coating produced in accordance with the present invention. Composition and microstructure analysis was performed: EDS / WDS was used to determine the uniformity of the distribution of Ti, Cr, and Ni (surface scanning deviation ≤ 5%); XRD was used to confirm the absence of harmful brittle phases (such as Cr3Ti and Ni3Sn4). Wettability testing was then performed: the wettability area was measured on a 45-grade steel surface (≥85% was considered acceptable, according to ASTM B898). Mechanical properties testing was then conducted, resulting in shear strength of ≥120 MPa (45-grade steel substrate, according to ASTM D1002) and high-temperature strength of ≥60 MPa at 800°C (simulating high-temperature operating conditions).

Claims

1. A method for preparing a molybdenum disulfide coating for a steel screw rod, characterized in that: Micron-sized MoS2 powder and copper-based brazing filler metal powder are mixed in a mass ratio of 3.2%-12.8% and then coated on the surface of the steel wire rod. Induction heating is then used to melt the brazing filler metal to achieve brazing coating adhesion, forming a molybdenum disulfide coating.

2. The method for preparing a molybdenum disulfide coating for a steel wire rod according to claim 1, wherein: This method comprises the following steps: a. Complete the pretreatment of the steel wire rod substrate to make its surface clean; b. Prepare MoS2 powder and copper-based solder powder, mix them evenly and apply them to the surface of the steel wire rod; c. Use induction heating equipment to induction heat the steel wire rod. During heating, control the surface temperature of the substrate to be higher than the melting point of the solder. After induction heating until the copper-based solder is completely melted, keep the temperature for 10-30 seconds, and then naturally cool it to room temperature; d. Smooth the surface of the product.

3. The method for preparing a molybdenum disulfide coating for a steel wire rod according to claim 2, wherein: In step a, the steel wire rod base material is 45 steel material.

4. The method for preparing a molybdenum disulfide coating for a steel wire rod according to claim 2, wherein: In step a, the steel wire rod substrate is pretreated by first cleaning it with acetone or alcohol, and then sandblasting the surface of the substrate; After cleaning and sandblasting, a layer of nickel with a thickness of 2-5 μm is first formed on the surface of the substrate by electroplating or chemical plating.

5. The method for preparing a molybdenum disulfide coating for a steel wire rod according to claim 2, wherein: In step b, the particle size of the micron-sized MoS2 powder is in the range of 1-10 μm; The MoS2 powder is prepared by ball milling into granular form and then dispersed using an ultrasonic dispersion process.

6. The method for preparing a molybdenum disulfide coating for a steel wire rod according to claim 2, wherein: In step b, when MoS2 powder and copper-based solder powder are mixed, an appropriate amount of starch is added as a binder, and then water is added and stirred evenly to form a spreadable fluid, which is then evenly sprayed onto the surface of the steel wire rod with a spraying thickness of 10-100um.

7. The method for preparing a molybdenum disulfide coating for a steel wire rod according to claim 2, wherein: In step c, the induction heating equipment uses a medium frequency of 10-50 kHz for induction heating; In step c, an infrared thermometer is used for real-time monitoring during heating to prevent the substrate from overheating; In step c, argon gas is used for protection during the heating, heat preservation and cooling processes.

8. The method for preparing a molybdenum disulfide coating for a steel wire rod according to claim 2, wherein: In the step d, a layer of impregnated resin-based MoS2 composite coating is provided on the surface of the brazing coating of the cooled product by means of impregnated resin composite.

9. The method for preparing a molybdenum disulfide coating for a steel wire rod according to claim 2, wherein: The copper-based solder has the following material composition ratios by mass: copper (Cu) 70-75 parts, tin (Sn) 15-20 parts, titanium (Ti) 0.5-1.5 parts, nickel (Ni) 1-2 parts, and chromium (Cr) 0.1-0.3 parts.

10. The method for preparing a molybdenum disulfide coating for a steel wire rod according to claim 9, wherein: The copper-based solder is prepared by the following preparation method: 1) Obtaining the material components of the mass ratio for use; 2) Each material is loaded into the melting furnace in order for melting. First, add Cu, Ni, Cr, and Ti. After melting at 1500℃ and cooling to 1150℃, add Zn and Sn. 3) Complete the melting according to the following requirements: the melting temperature is required to be 1150-1500℃; the melting atmosphere is required to be a vacuum or argon atmosphere; the stirring requirement is to stir at a speed of 200-300 rpm for 10-15 minutes; 4) Pour the smelted alloy melt into a water-cooled copper mold for rapid initial cooling at a cooling rate of ≥100°C / s, cooling the melt to 800°C; 5) The initially cooled alloy melt is pumped into an atomizing nozzle for spraying and forming into a spherical powder with a particle size of 20-75 μm under argon protection; 6) The spherical powder obtained by atomization is ball-milled using an ethanol medium with a ball-to-powder ratio of 5:1 to obtain a copper-based solder with a particle size of 1-10 μm.