Sintering in different atmospheres of T15 and M2 high speed steels produced by a modified metal injection moulding process

A study of the sintering behaviour of M2 and T15 high speed steel (HSS) parts obtained by a modified MIM process in low and high vacuum and in N2–5%H2 atmosphere, showed that high vacuum sintering gave quasi-full densities at very low temperatures in both steels. Microhardness is in relation to the densities obtained, and can be improved by conventional heat treatment. The evolution of the microstructure during sintering was analysed by SEM and XRD. After vacuum sintering M6C and MC carbides were detected whereas sintering in nitrogen rich atmosphere makes carbonitrides appear.