U71Mn大方坯凝固坯壳与结晶器铜管温度场的数值模拟

Numerical Simulation for Temperature Distribution of Initial Solidifying Shell with Mold Tube During Bloom Casting of U71Mn Steel

国内某钢厂为应对客户对重轨钢质量要求的不断提高,设计并制造了新的大方坯铸机,其中结晶器探索性地由组合式换为整体铜管式,材质为Cu-Ag,以提高铸坯质量。针对U71Mn重轨钢在新的管式结晶器中的冷却凝固的复杂性作者建立了包括结晶器与凝固坯壳之间动态热交换的综合热状态分析的热—力耦合模型,并利用Marc有限元大型计算分析软件进行了分析。所揭示的凝固坯壳与铜管温度场表明,管式结晶器完全适合U71Mn钢大方坯的浇注,并提高了坯壳角部温度分布的均匀性;同时表明,坯壳与结晶器壁之间的气隙变化对其热面温度有明显的影响。

A new complete mold tube with Cu-Ag alloy in stead of the original combined mold by separate copperplates was adopted in a domestic steel plant, which produces heavy rail steel by a newly commissioned bloom caster for higher quality products. To know clearly about the complex solidification of U71Mn steel in the new mold, a coupled thermal mechanical model was built which contained the mold tube and the initial solidifying shell for the prediction of the temperature distribution of the steel shell and the mold tube by FEM code Marc. From the analysis to the temperature fields of both steel shell and mold tube, it has been shown that the new mold tube is fit for the bloom continuous casting of U71Mn steel, which has better cooling effect on the comers of the bloom for quality production. The effect of gap between mold tube and the shell on the temperature field is described accordingly.