Abstract:Focus on the quality problem of SPA-H steel plate bending cracking occurred when user made container, the non-metallic inclusions and composition segregation at the crack site of bend crack sample were analyzed by scanning electron microscope, EDS and optical microscope, and the results were contrasted with uncracked samples. The results showed that serious phosphorus segregation at 1/4 thickness of steel plate broke the continuity of steel group and the fluidity of metal. The continuity of matrix was destroyed due to a mount of manganese sulfide inclusions near crack source and large particles of alumina inclusion was easy to form stress concentration, which could become the crack source. Cracking of steel plate during bending caused by combined action of serious phosphorus segregation and large amount of non-metallic inclusions.