High Temperature Wear Behaviour of High Speed Steel Thick Deposits Obtained by Laser Cladding

High Speed Steel (HSS) are Fe-Cr-C-based alloys containing very hard carbides such as V-rich MC, Mo- or W-rich M2C, Cr-rich M7C3 or M3C. Thanks to this complex microstructure, thick deposits of HSS have been found useful in a wide variety of applications including machining, cutting or hot strip mills. Recently, laser cladding has emerged as a very promising technique for the fabrication and repair of such thick coatings as the very high cooling and solidification rates imposed by this process result in strongly refined microstructures and potentially enhanced wear resistance.

In this study, the high temperature (i.e. at 300°C) wear behaviour of 3 different HSS thick deposits with varying Mo, V and W contents has been investigated and compared with a reference cast material. For all materials, the wear mechanisms have been identified as oxidative wear with contributions of third body abrasion and adhesion. Moreover, a detailed comparison of the wear behaviour of the 3 laser clad deposits, in correlation with their microstructure, allows for a deeper understanding of the effect of their different carbides types and morphologies.