軸受鋼の長寿命回転曲げ疲労における内部起点型疲労破壊挙動の強度レベル依存性

概要

論文の詳細を見る
Cantilever-type rotating bending fatigue tests were carried out on bearing steels tempered at three different temperatures in order to clarify the strength level dependence of the long-life fatigue behavior. For the surface induced fracture, it was found that the fatigue limit tended to decrease with a decrease of the specimen hardness and it was related to the half value breadth which was a typical parameter of X-ray diffraction. On the other hand, the fatigue life in the interior inclusion induced fracture was improved as the hardness was decreased. Based on the fractography of the fracture surface, characteristic rough surface of fine granular area (FGA) was observed in the vicinity around the interior inclusion. Formation mechanism of this FGA was discussed from microscopic observations by TEM and SIM and X-ray diffraction patterns. Thus it was finally found that the martensitelath was restructured as to give a number of microscopic subgrains and separation of the boundaries of these subgrains caused the fatigue crack producing the characteristic rough area of FGA.
社団法人日本機械学会の論文
2004-02-25