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.

A cellular automaton (CA) model has been developed to simulate the microstructure
evolution of ASTM A216 WCA cast steel during solidification and consequent cooling process. In the
model, the thermodynamics and solute diffusion of the multicomponent system were taken into account
by using Thermo-Calc and Dictra software. The peritectic solidification, α-ferrite/austenite transition and
eutectoid transformation as well as the final microstructure can be predicted. To validate the model, a sand
mold step-shaped casting was produced and metallographic examination was carried out, in which the
content and the grain size of proeutectoid ferrite were measured by using OM, and the
mean interlamellar spacing of pearlite was measured by using SEM. It was shown that the simulated
results are in good agreement with the experimental results. As the cooling rate increases,
proeutectoid α-ferrite content increased, while the mean grain size of proeutectoid α-ferrite
and the average lamellar spacing of pearlite decreased.