Research Of Arc Spraying Cored Wires And Coating Properties

Wear resistant arc spraying coatings deposited on workpiece can dramatically improve its sevice life. As arc spraying materials, Cr13 martensitic stainless steel cored wires are widely used in repairing mechanical elements and fabricating wear and corrosion resistant coatings.In this paper, the spraying processes of 4Cr13 martensitic stainless steel arc spraying cored wires were optimized. Effects of substrate's surface pretreatment processes, coating thickness and post-spraying heat treatment temperature on microstructure and properties were studied, as well as the arc spraying parameters which include spraying current, spraying voltage, spraying distance and air pressure.Martensitic stainless steel and high alloy steel wear resistant cored wires which contained Mo, V and Nb were made to prepare coatings. The microstructure, porosity, microhardness, wearing resistance and bonding strength was tested. And the formula of cored wires was optimized. The effects of Mo, V and Nb on microstructure and properties of coatings were investigated.The results show that the best spraying process for 4Cr13 cored wires is as follows: Spraying base coating after sandblasting is the best surface pretreatment process. The optimum spraying parameters are: spraying current 240A, spraying voltage 30V, spraying distance 200mm and air pressure 0.5MPa. And the optimal thickness of coatings is 0.6mm. The best post-spraying heat treatment temperature is 550℃～650℃.The best formula of martensitic stainless steel cored wires is: ferromolybdenum 6%, ferrovanadium 4%, ferroniobium 6%, and ferromolybdenum 6%, ferrovanadium 2%, ferroniobium 8% for high alloy steel cored wires. The effects of Mo, V and Nb on properties of martensitic stainless steel and high alloy steel coatings are similar. Mo has the biggest impact on porosity of coatings, Nb second, and V the least. V has the greatest effect on microhardness and wearing resistance, Nb second, and Mo the least. The bonding strength between coating and substrate depends on the porosity and continuity of the coating. V has the strongest influence on continuity, Nb second, and Mo the least. When the content of the element which has great influence on coating properties increases, the porosity and microhardness increases, the wearing resistance gets better and the continuity of coatings becomes worse.