INCREASING THE WEAR RESISTANCE OF ROAD TRANSPORT PARTS IN THE AGRO-INDUSTRIAL COMPLEX BY APPLICATION OF LASER DEPOSITION

Abstract

In this work, we studied the effect of laser melting and alloying elements (ТаВ, МоВ, B4C) on the friction coefficient and wear rate of plasma coatings of automotive parts in the agro-industrial complex under friction conditions both without lubricant and with lubricant. Under friction without lubrication, the main factors that determine the wear resistance of the part are the hardness of the alloyed layer and its chemical composition. The content of molybdenum, tantalum and boron carbide borides in the surface layer, which provide the formation of secondary structures separating the friction surfaces, has a favorable effect on the coefficient of friction, and, consequently, on the operational characteristics of the surface. As a result of the research, the following trend was revealed: coatings with a lower coefficient of friction also have the least weight wear and are the most wear-resistant. Alloying with tantalum boride increases the heat resistance of coatings, leads to grain refinement in them, and an increase in microhardness. Therefore, this coating can be recommended for operation in conditions of friction without lubricant and high pressures. Studies have shown that the wear resistance of coatings is affected by laser processing modes, contact load, the method of reflow of a gas-thermal coating, as well as its chemical composition. The choice of laser processing modes provides control over the structure and properties of coatings, and also affects their wear. Also, as a result of studies under friction conditions with a lubricant, it was determined that the coating after laser alloying with molybdenum boride has the lowest coefficient of friction and wear resistance. This can be explained by the fact that laser doping of iron-based coatings with molybdenum boride increases their heat resistance. This is important at increased loads on the test sample. In addition, molybdenum, interacting with atmospheric oxygen and lubricant, forms molybdenum oxide, which further reduces the coefficient of friction. Therefore, the coating after laser alloying with molybdenum boride can be recommended for operation under conditions of friction with a lubricant at elevated pressures.