Preparation And Properties Of Structural Coupling Self-lubricating Wear-resistant Coating For Drawing Die

The drawing die is an important production tool in the manufacturing fields of automobiles,aerospace,and household products.Due to the shape limitation of the drawing part during the forming process,the metal fluidity of different parts has different requirements on the friction of the forming die.In theory,there is an optimal friction characteristic distribution.In this regard,according to the friction characteristic distribution theory existing between the mold and the plate,this paper puts forward the design scheme of the structure coupling self-lubricating wear-resistant coating.Traditional laser cladding wear-resistant self-lubricating coatings are prepared based on metal matrix composite materials,which have various shortcomings.For example,the mutual reaction between materials during the metal cladding process affects the overall performance of the coating;The performance of the coating tends to be consistent,and the wear resistance and self-lubricity of the area cannot be flexibly controlled.In this paper,a laser cladding process and a vacuum thermal diffusion welding process are used to prepare the wear-resistant unit and the self-lubricating unit,respectively,to obtain a self-lubricating wear-resistant coating with an alternating structure.This article starts from three aspects: scheme feasibility analysis,coating design and coating performance testing.The experiment first explored the structural scheme,and determined the preparation methods of laser cladding to produce wear-resistant units and vacuum thermal diffusion and self-lubricating units.Subsequently,the parametric performance of the laser cladding coating and the optimal structural parameters of the self-lubricating unit were explored.Finally,a coupling coating with synergistic effect was successfully obtained.The microstructure and phase composition of the coating were analyzed using SEM,XRD and EDS;the tribological properties and transfer film formation mechanism were tested by linear reciprocating dry friction tests.Based on the structurally coupled new wear-resistant self-lubricating coating,the flexible design of the wear-resistant units and self-lubricating units on the mold surface is realized,and the friction performance can be controlled flexibly by controlling the parameters of the two units’ distribution ratio and coupling mode.At the same time,the preparation method of the partial process avoids the problems of coating interference and failure caused by the process.The abrasive coating has good tribological properties,and its friction coefficient is less than 316 L stainless steel and H13 hot work die steel,and even lower than pure self-lubricating coating.This is because the structure-coupled self-lubricating wear-resistant coating forms a transfer film with self-lubricating properties during the friction and wear process,which reduces the friction resistance.The wear-resistant unit supports and stores solid self-lubricating materials,thereby reducing friction.In this form,the two units form a wear-resistant self-lubricating synergy.