Q235B钢矩形坯结晶器锥度优化研究

Study on Mould Taper Optimization for Q235B Steel Rectangular Billet

根据某钢厂连铸机实际生产情况,建立Q235B钢矩形坯的热力耦合模型。根据此钢的传热和凝固特点,利用有限元软件ANSYS对结晶器内铸坯传热进行数值模拟,以对结晶器锥度进行优化。结果表明:原结晶器锥度较小,"热点"区域坯壳生长缓慢,造成铸坯偏离角部处开裂。坯壳表面最大温差为298℃。在距弯月面190 mm处,铸坯角部温度的下降速度减慢,且逐渐高于表面中心温度,"热点"区域坯壳厚度比表面中心薄2.4 mm。锥度优化后,结晶器内"热点"现象消除,结晶器出口处铸坯表面中心温度从1 544℃下降到978℃,角部顶端温度从1 544℃下降到753℃,结晶器出口处距角部15 mm区域坯壳厚度从16.6 mm增加到22.0 mm,有效降低了角部裂纹发生率。

Based on the actual production situation of the continuous casting machine in a steel plant, a thermo-mechanical coupling model for the Q235B steel rectangular billet was established;and according to the heat transfer and solidification characteristics of the steel,the finite element software ANSYS was used to simulate the heat transfer of the billet in the mould,to optimize the taper of the mould.The results showed that the taper of the original mold was small,and the shell grew slowly in the "hot spot"area,resulting in cracking in the point deviating from corner of the billet.The maximum temperature difference at surface of the billet shell was 298 ℃.At a distance of 190 mm from the meniscus,the temperature at corner of the billet falled down slowly and was gradually higher than that in center of the surface,and the thickness of the billet shell in the "hot spot"region was 2.4 mm thinner than that in center of the surface.After taper optimization,the phenomenon of"hot spot"in the mould was eliminated,the temperature in center of the billet surface at exit of the mould decreased from 1 544 to 978 ℃,the temperature at the corner top decreased from 1 544 to 753 ℃,and the thickness of the shell increased from 16.6 to 22.0 mm in the area 15 mm from corner at the exit of the mould,which effectively reduced the occurrence of corner cracks.