Cr-Mo鋼のレーザ焼入れに及ぼす炭素含有量の影響に関する変態・熱・力学的解析

抄録

The numerical simulation of the pulsed YAG laser-hardening process of three kinds of Cr-Mo steel containing different carbon by use of the heat treatment simulation code “HEARTS” is implemented based on metallo-thermo-mechanics developed by the authors. The effects of carbon content on the characteristics of laser-hardened material are investigated. As the obtained results, more severe heating and cooling rates are need for the steel with higher carbon content, and the position near the laser irradiated surface on optical axis is heated up to the highest temperature. The austenite transformation in this case is accomplished in remarkably short time, and progresses from the heated surface. The martensite transformation is observed at lower temperature for carbon rich steel and is produced from inside of solid by self-cooling effect. Induced stresses during and after hardening process increase with higher carbon content.