电渣重熔M2高速钢铸锭的组织均匀性

Microstructure homogeneity of high speed steel M2 ingot by electroslag remelting

利用实验结合数值模拟的方法研究了直径为400mm的电渣重熔M2高速钢铸锭的组织均匀性,比较了靠近铸锭中心及边缘的微观组织差异,分析了局部凝固时间对共晶碳化物形态的影响规律。结果表明,靠近中心区域为粗大的柱状晶,莱氏体共晶包直径从100μm到400μm不等,共晶碳化物层片最宽可达几十微米,长度可达一百多微米。计算得到铸锭心部的局部凝固时间最长约1 300s。而靠近铸锭边缘处,柱状晶更加细小,共晶包直径介于50~200μm之间,共晶碳化物层片宽度约10μm左右,长度约几十微米。计算得到铸锭边缘的局部凝固时间最短为365s。电渣锭凝固至准稳态时,金属熔池呈锅底状,实测熔池深度约178mm,与模拟结果基本吻合。

The homogeneity of the microstructure in M2 high speed steel ingot with a diameter of 400 mm was studied by means of electroslag remelting process combined with numerical simulation.The microstructure differences between the center and the edge of the ingot were compared.The effects of local solidification time on eutectic carbides were discussed.The result shows that the size of the eutectic colonies varies from 100μm to 400μm near the center of the ingot,and lamellar eutectic carbides can reach a maximum thickness of tens of microns,and a length of more than 100μm.The maximum local solidification time is about 1 300 sat the center of ingot by calculation.Close to the edge of the ingot,the columnar crystals become small,and the size of eutectic colonies is among 50-200μm,and eutectic carbide lamellae are about 10μm in width,and tens of microns in length.The local solidification time at the edge of ingot is as short as 365 s.When solidification of the ingot becomes quasi-steady state during electroslag remelting,the metal pool is pot-bottom-like.The pool depth is about 178 mm by experiment,and the calculated pool depth is in accordance with that of experiment.