Design And Study On Tribological Of WS₂/Zr Composite Coating Surface On Drawing Dies

Drawing processing is one of the main technical means of wire rod production.In the wire drawing forming process,the metal raw material undergoes plastic deformation through extrusion and drawing in the working area of the drawing die,so that the wire diameter conforms to the production process requirements.The working surface of the die is subjected to drawing and extrusion of the wire,which is often subjected to high temperature and high pressure and severe wear,and the working surface of the die wears rapidly.Therefore,the development of a new drawing die has important significance for the wire industry.The emergence of solid self-lubrication coatings has provided new ideas for solving this problem.WS₂ materials,as a solid self-lubricating material developed in recent decades,have the functions of anti-friction,anti-wear and lubrication,and can improve the tribology of the base material.characteristic.YT15 cemented carbide was used as the matrix material in the drawing tool.The Zr transition layer was prepared by DC magnetron sputtering and the WS₂ coating was prepared by RF magnetron sputtering.The WS₂/Zr composite coating was finally prepared.By optimizing the preparation process,the influence of magnetron sputtering process parameters on mechanical and tribological properties of WS₂/Zr composite coating was studied.The best preparation process of WS₂/Zr composite coating was determined as follows:RF sputtering power 90W,substrate temperature 200°C,argon working pressure is 0.4Pa.Based on the related theories of thermodynamics,the residual thermal stress simulation of the coating cooling to room temperature after the preparation was carried out through finite element simulation software.The residual thermal stress analysis model of the coating was established and the residual thermal stress distribution cloud diagram of the coating was obtained when the coating was from 200°C.When cooled to 20°C,the Zr transition layer was set to reduce the residual thermal stress of the coating and the substrate to 280 MPa,and the high stress gradient region was transferred from the edge of the WS₂ junction with the substrate to the edge of the junction of the Zr transition layer and the substrate.The microstructure of the composite coatings with different process parameters was prepared and the mechanical properties were tested.The results show that when the RF sputtering power is 90W and the sputtering temperature is 200°C,the composite mechanical properties of the WS₂/Zr composite coating are excellent.The substrate matrix has good bonding force and the coating microhardness is 600HV,which is higher than that of the pure WS₂ coating.The coating thickness is between 4-5?m.Under different loads,the friction and wear test of the composite coating was carried out and found that the composite coating maintained good friction and wear properties within a certain test time,and the friction coefficient was maintained at a relatively good level under low load;within a certain load range,The increasing friction coefficient of the load gradually decreases.WS₂ coating material and the formation of an effective transfer layer on the surface of the ball is the key to the material's good tribological properties.The formation of an effective transfer layer makes the direct friction between the coating and the grinding ball into the interlayer friction of the WS₂ material,which plays an important role in reducing the friction coefficient of the base material and enhancing the friction and wear performance.