Determination of mechanical and tribotechnical properties of coatings during laser surfacing of tool steels

Abstract

The paper considers the results of metallographic studies and tribotechnical tests of samples of 9CrSi tool steel and multicomponent coatings obtained by laser surfacing with the addition of ultrafine titanium carbide particles into the charge. As an additional parameter, transverse high-frequency oscillations of the beam along the normal to the velocity vector of the laser surfacing were used. Tribotechnical tests were carried out according to the scheme “the plane is the end of an annular 40Cr steel plate with volumetric hardening”. To determine the critical sliding speeds, the tests were performed at a constant pressure of 2.5 MPa. Industrial I20 oil was fed into the friction zone. The minimum values of the friction coefficients depending on the sliding speed were obtained when 7 vol% titanium carbide was introduced into the multicomponent charge. The sliding speed to the bully increases by 2, 2.7 and 3.5 times when surfacing with a multicomponent charge without carbides and with the introduction of 4 and 7 vol% titanium carbide, respectively. Coatings with a high content of the hardening phase had the greatest wear resistance. Laser surfacing technology can be applied to the restoration of worn surfaces of rolls of rolling mills, die-cutting dies and other parts of die tooling.