SURFACE ENGINEERING OF LOW CHROMIUM AND MOLYBDENUM PM STEELS BY PLASMA TREATMENTS

摘要

Plasma carburizing and plasma nitriding are practically insensitive to density and open porosity and form controlled case depths on AstaloyCrM based sintered steels. Both treatments improve rolling contact fatigue behaviour of the materials and reduce impact resistance, which however remains on acceptable levels. Warm compaction and high sintering temperature increase mechanical properties of the base material, in particular toughness, and the positive effects are maintained after surface treatments. The results may be further improved by exploiting the flexibility of plasma technology.