工艺因素对SCM435钢大方坯凝固组织的影响

Effects of technological factors on solidified microstructure of cast bloom of SCM435 steel

为了模拟不同工艺条件下的连铸坯的凝固组织,采用有限元法模拟了SCM435钢的连铸凝固过程,获得了325 mm×280 mm连铸坯的温度场,在此基础上与元胞自动机(Cell automaton,CA)耦合模拟凝固组织.结果表明,随浇注温度的降低,柱状晶区逐步减少,表面细晶区及中心等轴晶扩大,晶粒密度逐步增加,最大晶粒面积及平均半径大大减少;但中心凝固所需要的时间反而有所增加,中心处的晶粒的平均半径先降低后升高;拉速对凝固位置的影响较为显著,随拉速的增加,晶粒密度逐步减少,柱状晶宽度与中心处的等轴晶半径略有增加.

In order to simulate solidification structure of the bloom continuous casting under different technological factors,the solidification process of SCM435 steel were simulated by using finite element method,and a temperature field of 325 mm×280 mm for casting bloom was obtained.The solidification microstructures were simulated by using coupling cellular automaton(CA).Results showed that with decrement of the pouring temperature,the columnar crystal zone decreased,surface fine-grain,equiaxed crystal zone and grain density increased,and max grain surface and mean grain radius decreased.But center solidification required more time,grain radius of center declined firstly and then increased;Position of solidification was obviously impacted by casting speed.With the decreasing casting speed,grain density gradually reduced,and width of columnar crystal and equiaxed crystal radius in center of bloom had a slight increase.