Abstract

The metallographic changes taking place in three T grade steels, T42, T15 and T1 in the range of optimum sintering temperature to oversintering in vacuum and in an industrial atmosphere - base nitrogen - have been investigated using SEM and EDS techniques. M6C and MC primary carbides have been observed for vacuum sintering and MX carbonitrides instead of MC carbides were found in the specimens sintered in the atmosphere. Small amounts of an eutectic carbide rich in Cr and Fe have been observed at the optimum sintering temperature. By oversintering in vacuum different type of eutectic carbides can be observed: MC, needle shape, M6C, but only M6C type eutectic carbide have been observed by oversintering the samples in the industrial atmosphere.