Analysis on Premature Fracture of Top Rod of H13 Steel

Premature fracture of top rod of H13 steel was analyzed by physical test and chemical analysis.The results show that the cause of crack formation was the excessively high heating temperature while forging the mould.The burnt structure of intergranular molten holes was formed,and the strength and toughness property of the mould degraded significantly.In addition,the amount of non-metallic inclusion and the eutectic carbide of the raw material exceeded the standard,which led to the material property further degraded and the mould fractured while forging.The crack continued to extend during use,and finally resulted in the premature fracture failure.