Experimental Research on Crack Propagation in U71 Mn and U75V Rail Steels

摘要

In this paper, the continuous in-situ observations of the fatigue crack growth in U71 Mn and U75V rail steel are made by using the scanning electronic microscope (SEM). The microstructure patterns of cracks under the mode I fatigue loads and quasi-static loads are presented. The results indicate that the short fatigue crack growth in rail steel is a quasi-cleavage fracture. The ductility and the performance of fatigue resistance of U71Mn rail steel are better than those of U75V rail steel.