Abstract： Aiming at the crack defect on the plate surface of plastic mold steel SM50 in Tangshan steel, the causes of crack were analyzed in depth by means of production process investigation, energy spectrum analysis and metallographic analysis. The result showed that the surface crack defect of SM50 steel plate was not caused by the original cracks of the casting slab, but the hotpacked crack caused by the extremely uneven grain size of the cast slab due to the hotfilling of the continuous casting billet in the twophase region. Through improving the existing production process, the improvement measures of slow cooling and warm loading of casting billet into the furnace were proposed. After the new process was implemented, the proportion of cracks in the hotpacked crack of SM50 steel decreased from 4.24% to less than 0.30%, and the surface crack rate of steel plate decreased significantly.
张锦兴，孔明姣，任树洋，马建锋，吴建国. 塑料模具钢SM50钢板表面裂纹成因及控制措施[J]. 中国冶金, 2019, 29(4): 70-74.
ZHANG Jinxing，KONG Mingjiao，REN Shuyang，MA Jianfeng，WU Jianguo. Cause and control measures of plate surface cracks for plastic mould steel SM50[J]. China Metallurgy, 2019, 29(4): 70-74.
2019, Vol. 29 
