Reasons for cracking in automotive sheet stamping for ultra deep drawing

A certain ultra deep drawing automotive sheet experienced stamping cracking. The cause of cracking in automotive sheet was analyzed by macroscopic observation, scanning electron microscopy and energy spectrum analysis, metallographic examination. The results show that during the hot rolling process, weld beads appeared on the surface of the strip steel and detached objects were produced. The detached objects were embedded into the surface of the strip steel after rolling, ultimately led to stamping cracking of the automotive sheet.