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结合Thermo-Calc和Dictra软件考虑了多组元条件下的凝固和溶质扩散过程,建立了元胞自动机(CA)模型,对ASTM A216 WCA铸钢凝固及后续冷却过程的相变进行了模拟.设计了阶梯形试件进行浇注与测温实验,并用OM和SEM观察了铸态试件不同部位的微观组织,测定了先共析α铁素体的含量及其晶粒尺寸、珠光体的层片间距,并将数值模拟结果和实验结果进行了对比,分析了冷却条件对铸态微观组织的影响.结果表明,模拟结果与实验结果符合良好,随冷却速率的增大,先共析α铁素体的含量增加,同时,先共析α铁素体的平均晶粒尺寸和珠光体的平均层片间距减小.
The combination of Thermo-Calc and Dictra software was used to consider the solidification and solute diffusion processes under multi-component conditions. A cellular automata (CA) model was established to simulate the phase transition of ASTM A216 WCA cast steel during solidification and subsequent cooling. A step-shaped specimen was designed for pouring and temperature measurement. The microstructure of different parts of as-cast specimen was observed by OM and SEM. The content of the first eutectoid α-ferrite and its grain size were determined. The results show that the simulation results are in good agreement with the experimental results. With the increase of the cooling rate, the α-Fe The content of the ferrite increases, meanwhile, the average grain size of the first eutectoid alpha ferrite and the average interlamellar spacing of the pearlite decrease.