低合金焼結鋼製部品の形状に応じた2次処理条件の最適化の検討

抄録

In order to expand PM business, the improvement of dynamic mechanical properties and the repertory of such data are necessary. We have thought for long time that partially diffusion bonded alloy is more suitable to achieve higher fatigue strength. It is true for the component under some process conditions. However, the level of density for PM components is improving today. The combination of both high density and optimization of secondary operations showed that pre-alloyed material was more suitable to achieve much higher fatigue strength than partially diffusion bonded alloy. Then some studies to improve fatigue strength were presented.
This paper introduces the improvement of fatigue strength by applying shot peening process and discusses the mechanism of improvement of fatigue strength by considering stress profile. The influence of geometry on stress profile has also been discussed, including the FEM analysis of actual transmission gear to describe the optimum secondary operations for each component.
The possibility to apply PM components for an actual transmission gear has been discussed in this paper by calculating safety factor with the root stresses measured of the embedded gear in an actual transmission gear box.