连铸结晶器内矩形坯的温度场模拟

Thermal Field Simulation of In-Mold Continuous Casting of Rectangular Blooms

利用有限元法建立了结晶器内轴承钢矩形坯温度场数学模型.采用了随温度变化的热物性参数,并且在边界条件中采用平均热流、瞬时热流及角部气隙等对比分析,研究了不同边界条件下矩形坯的温度场和坯壳厚度.模拟结果表明：不考虑角部气隙时,采用平均热流边界条件时矩形坯的温度范围要比采用瞬时热流时范围大;考虑角部气隙时,温度范围相差不大;角部气隙只对角部区域的温度有影响,而对芯部、宽面中心、窄面中心等区域基本没有影响;气隙降低了坯壳表面的换热,使得角部坯壳厚度要比不考虑角部气隙时平均小6~7 mm左右,在距离角部30 mm处出现热节区.

A mathematical model describing the in-mold temperature contour for a GCr15 rectangular bloom was determined using FEM.Temperature-dependent thermophysical parameters along with average heat flow,transient heat flow,and corner air gap in boundary conditions were used to study temperature contour and billet shell thickness of rectangular blooms under different boundary conditions.Simulation experiments indicated that the temperature range with an average heat flow boundary was wider than that with transient heat flow when not considering the air gap.With the air gap,however,the ranges were similar.Corner air gap only affected the temperature of the corner region,while the core,wide face center,and narrow face center regions were not affected.Corner shell thickness with an air gap was 6 to 7 mm narrower than the one without air gap,and the hot spot area appeared 30 mm away from the corner.