Fatigue Strength of Sintered and Carburized Compacts Made of Molybdenum Hybrid-Alloyed Steel Powder

摘要

The fatigue strength of the sintered and carburized compact made of the Mo hybrid-alloyed steel powder, which is based on a molybdenum prealloyed steel powder to which Mo powder particles have been diffusion bonded, is higher than that of the Mo prealloyed steel powder. The sintered compact made of the Mo hybrid-alloyed steel powder has a finer pore structure than that of the Mo prealloyed steel powder, because the Mo-rich region near the surface of the Mo hybrid-alloyed steel powder should exist as the a-iron phase with a high diffusion coefficient at high temperature and result in enhanced sintering. Improvement in the fatigue strength of the sintered and carburized compact made of the Mo hybrid-alloyed steel powder should result from not only the fine pore structure but also the strengthening of the sintering neck by Mo concentration around pores.