Cr5支承辊接触疲劳损伤及其次表层组织变化

针对支承辊使用过程中的疲劳失效现象，利用光学显微镜(OM)、扫描电子显微镜(SEM)、透射电子显微镜(SEM)、显微压痕仪和X射线应力仪等对滚动接触疲劳前后Cr5支承辊钢次表层组织进行了研究.结果表明，支承辊在交变接触应力作用下发生接触疲劳损伤，疲劳损伤最大值位于距表面约400μm的支承辊次表层.疲劳损伤引起支承辊次表层硬度升高，残余应力减小，耐腐蚀性增强.疲劳硬化层微观组织发生破碎，位错密度升高.在接触应力不变的情况下，支承辊滚动接触疲劳损伤程度随着寿命比例的增加而增大.

Contact Fatigue Damage and Subsurface Microstruture of Cr5 Backup Roll

Optical microscope (OM)， scanning electron microscope (SEM)， transmission electron microscope (TEM)， micro-indentation tester and X-ray stress meter were employed to investigate the microstructure of backup rolls’ subsurface after rolling contact fatigue. The maximum value of fatigue damage was located on the subsurface of the backup roll which was about 400μm away from the surface. The increased hardness， reduced residual stress and elevated corrosion resistance of the subsurface resulted from rolling contact fatigue. Microstructure of the subsurface was broken into small pieces and dislocation density was increased. Under one constant contact stress， fatigue damage of backup roll increased with the increasing percentage of fatigue life.