Meso mechanical Investigation of Fatigue Crack Propagation in 16MnR Steel

The fatigue experiments were conducted on one side notched specimens of low carbon steel 16MnR,by using microscopic fatigue testing device. Some characteristics of short crack initiation and propagation were examed.The experimental results show that there are three stages of short crack propagation.Each stage showes its own features.The first stage shows brittle appearence without slip bands.The second stage shows limited slipping within limited area. At the final stage of crack propagation,the main characters of the crack development are increasing small crack density,forming damaged area,and then choosing one of the small crack as main crack to develop.