Studies have been made concerning the heat treatment response of two high speed steels (HSS), M42 and T15 plus graphite and copper-phosphide powders. The green compacts were successfully sintered to full density in industrial atmosphere processes and could be hardened by conventional HSS heat treatment methods, namely quenching from high austenitization temperature followed by triple tempering to develop maximum hardness. The sintering temperature were 1100 and 1150 °C for M42 and T15 respectively. It was found that in the sintering process, nitrogen is incorporated in the steel powders (0.12 wt% for M42 and 0.11 wt% for T15). The heat treatments consisted in austenizing in the range of 1080 to 1130 °C for 3 min., oil quenching and triple tempering for lh. at each stage in the temperature range of 430 to 580 °C. Accordingly, the maximun hardness of T15 was 775 HV(10) and 827 HV(10) M42. Both, optical and SEM metallographic examinations were performed by which martensite, copper-rich solid solution, retained austenite and iron-rich phosphide phases were identified in both steels. The amount of retained austenite (17 and 45 vol.%) was measured by means X-ray diffraction technique, using the XPROFAN program to calculate the integrated intensities of the austenite and martensite phases.
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