Influence of gas atmosphere and hard particle addition on the sintering behavior of high alloyed PM cold work tool steels

Sintering of two different gas atomized PM cold work tool steels, X220CrVMo13-4 (X220) and X245VCrMo9-4 (X245), in argon, nitrogen and forming gas (N2–5% H2) was investigated with respect to the atmospheric influence. To ascertain the influence of hard particle additions, coarse powders of TiC and WC/W2C were mixed with the steel powder at a volume fraction of 5 vol.%. The objective of these investigations was to detect optimal sintering parameters for the processing of sintered wear resistant metal matrix composites. Additionally, the disastrous influence of fused tungsten carbide particles added to tool steel powders during sintering ought to be clarified. Experiments were carried out using dilatometry, high temperature X-ray diffraction, protective gas sintering and scanning electron microscopy. To support the experiments theoretically, pressure dependent Thermo-Calc calculations were performed.