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H13热作模具钢属于中碳钢,钢中的Cr、Mo、V含量较高,因此钢在凝固过程中这些碳化物形成元素会偏聚析出大量的网状碳化物,经过热处理也很难完全消除,从而降低了钢的性能。实验室条件下研究了向H13钢中加入不同含量的镁对钢中碳化物的影响。结果表明:微量的镁能够改善H13钢中碳化物的形状和分布,使碳化物由粗大的网状转变成细小的短条状,经过镁处理后,碳化物呈细小均匀地分布在钢中。当加入0.004%的镁时,对碳化物的改质效果最好。镁在晶界处的偏聚是改善碳化物分布的主要原因,通过理论分析发现,在钢凝固冷却的过程中镁元素在晶界处的偏聚程度较高,从而阻碍了碳化物的生长,达到细化碳化物的目的。
H13 hot work die steel belongs to the medium carbon steel, the content of Cr, Mo, V in the steel is high. Therefore, these carbides will form a large amount of network carbides during the solidification of the steel, which is difficult to be completely heat-treated Elimination, thereby reducing the performance of steel. Under laboratory conditions, the effects of adding different amounts of magnesium on the carbides in steel were studied. The results show that trace amounts of magnesium can improve the shape and distribution of carbides in H13 steel, and make carbides transform from coarse meshes into fine short strips. After magnesium treatment, the carbides distribute uniformly and finely in steel. When adding 0.004% magnesium, the modification of the carbide is the best. The segregation of magnesium at the grain boundaries is the main reason to improve the distribution of carbides. The theoretical analysis shows that magnesium is highly segregated at the grain boundaries during solidification and cooling, which hinders the growth of carbides. To achieve the purpose of refining the carbide.