Abstract The microstructure and hardness of two cracked failed steel (42CrMo4) teeth from different yaw rings have been investigated. It is shown that the surface quenching tempering treatments introduce heterogeneous microstructures with a low-temperature tempered hard martensite layer high-temperature matrix. This common to both teeth, however, gradient are for these rings. suggested this dif...

Abstract The paper contains the results of an experimental investigation fatigue crack development under mixed-mode I + II and III in heat-treated 42CrMo4 steel. Tests were performed on compact tension shear specimens rectangular cross-section for III. Mixed-mode tests conducted 30 60° loading angle, while test was 45°. Additionally, presents fracture analysis path development.