Increasing the wear resistance of agricultural machinery parts by laser surfacing

The paper presents the results of metallographic studies and tribotechnical tests of coatings containing in the composition of the charge a powder based on iron and nickel in a ratio of 4:1 and powder of ultrafine tungsten carbide (WC) 5 and 7 wt.%. Slip coatings were applied to 65Mn steel samples using an oxy-ethyl cellulose based binder. Coatings deposited by a laser beam were obtained when exposed to a defocused and oscillating laser beam. It was found that the performance of laser surfacing using transverse vibrations of the laser beam is 1.5-2.1 times higher than when processing with a defocused beam. The maximum values of microhardness 942-1190 HV were obtained when 7 wt.% WC was introduced into the charge. Scanning electron microscopy methods have established that the distribution of the charge elements along the height of the deposited layer is fairly uniform. Abrasive wear tests were performed according to the scheme: “the wide side of the flat sample is the annular surface of the rubber disc.” Quartz sand was fed into the friction zone using a dispenser. It was found that the abrasive resistance of a multicomponent charge and with additives of 5 and 7 wt.% carbides, respectively, is 2.45, 3.29, and 4 times higher than the base material of 65Mn steel.