Abstract
The paper presents the results of metallographic studies and tribotechnical tests of samples of medium-carbon steel 34KhNi3MoA and coatings obtained by laser surfacing of a powder multicomponent charge based on iron and cobalt in a ratio of 3:1 with additives of nano particles of tantalum carbide. The samples were processed with a circular defocused beam and with transverse beam oscillations normal to the scanning speed. Comparative tests for friction and wear were carried out in a pair with a hardened 40Kh steel counterplate. The load and sliding speed during the tests varied discretely. Turbine oil TP 22C was used as a lubricant. It is shown that the introduction of additives of nano-tantalum carbide into the charge reduces friction losses, increases the wear resistance of coatings compared to the charge without carbides and the base material. The wear resistance of coatings with an increase in the amount of the hardening phase increases compared to the original steel. It has been established that the technology of laser surfacing with multicomponent coatings with nano particles of tantalum carbide can be used to restore worn surfaces of shaft necks, turbine blades, thrust discs, shut-off valves and other parts operating at high temperatures and in corrosive environments.