ANALYSIS ON HORIZONTAL CRACKING OF RAIL FLASH WELDING JOINT

The cracking fractures of U75V rail flash welding joint were inspected using metallographic microscope and SEM. A lot of dimples wood grain area was found in crack source, and the cracks expanded from the other side of rail to weld and stopped at weld. The decarbonization on surface of the cracks confirm the cracks generate in high temperature period of weld,so it is welding hot crack.