Q345D钢厚板坯连铸结晶器内凝固过程数值模拟研究

Numerical simulation on solidification in mould for continous cast of heavy Q345D steel plate

为研究连铸过程中相关工艺因素对铸坯在结晶器内凝固的影响,采用商业有限元软件ANSYS,利用单元生死技术,研究结晶器中δ铁素体含量、拉速及过热度对300 mm厚Q345D板坯凝固过程的影响。分别获得δ铁素体含量、拉速及过热度对宽边截面上沿结晶器高度方向上出结晶器表面温度、坯壳厚度的变化规律。结果表明,铁素体含量、拉速及过热度的提高都会使坯壳沿结晶器高度方向的表面温度和厚度在距弯月面180 mm处呈周期性波动,波动范围为100 mm左右;当拉速为1.0 m/min、过热度为40℃及包晶反应中铁素体转变含量为100%时,温度差和厚度差波动幅度最大,此时温差为364.49℃,厚度差为6.17 mm。

In order to study the influence of relevant technological factors on the slab during the continuous casting solidification process in mould,a commercial ANSYS finite element model was established to simulate the influence of δ ferrite content,casting speed and degree of superheat on continuous casting solidification process of Q345 D slab according to the element birth and death technology. The influence law of δ ferrite content,casting speed and degree of superheat on surface temperature along the casting direction and the shell thickness was gained. The results indicate that the increases of δ ferrite content,casting speed and degree of superheat can give rise to a periodic fluctuation for the whole surface temperature of mould along the casting direction and the shell thickness,which occurs below the meniscus 180 mm,and the period is about 100 mm. In addition,when the casting speed reaches 1.0 m/min,the degree of superheat achieves 40 ℃,the δ ferrite content during the peritectic reaction arrives at 100%,the amplitude of fluctuation of surface temperature and shell thickness will be the greatest,at which the temperature difference is 364.49 ℃,and the shell thickness difference is 6.17 mm.