Wear Resistance and Characteristics of the Friction Surface of Metal Coatings with Nitride-Boride Alloying

The wear resistance and characteristics of the friction surface of metal coatings with nitride-boride alloying are investigated. The object of the study was the steel deposited with flux-cored wire containing 15% chromium, 0.5% boron nitride, 1.25% titanium di-boride and 0,5% zirconium di-boride. It was established that the average value of the relative wear per test was 0.00416 g/m, which is 1.8 times less than that of the coating metal without borides. The average value of linear wear was 0.0122 mm/m, which is 1,9 times less than that of the coating metal without borides. The average value of the friction torque for the entire friction path in 339 m was 20.96 Nm. The coefficient of friction was 0.425. The hardness of such a metal reaches a maximum value of 57 HRC. The micro-hardness of structural objects is for the matrix 617-648 HV, eutectic 764-847 HV and strengthening phases 1128-1247 HV. It is shown that the metal structure is an iron-chromium martensitic matrix with a eutectic component, formed on the basis of boride (Fe, Cr)2B and high-strength nitride ε-(Fe, Cr)2-3N, which is an effective obstacle to dislocation slip under conditions of plastic deformation of the surface at wear.