熱間工具鋼の疲労強度特性

抄録

In this study, Fatigue Strength of Hot Work Tool Steel SKD61 was investigated. Development of new-style hot work tool steel of SKD61 is advanced at present. Data about the fatigue strength which changed the training ratio of hot work tool steel are poor. A static bending test and fatigue test were curried out an examination sequentially to make fatigue strength clear and investigated it for the observation of the fracture surface using SEM and EDX. In the case of a training ratio change, it was found that static bending strength of K materials was same as that of reference materials. K materials had lower fatigue strength than reference materials over a range of number of cycles from 10⁴ to 10⁷. As a result of fracture observation, the fracture origin was aluminum and oxygen mainly. Because alumina (Al₂O₃) to use at the time of deoxidation as a probable cause remains behind, it becomes the destruction fracture origin.