多芯复合浇铸钢锭的硫代硫酸钠模拟实验研究

Simulation Experiment of Multi-core Composite Casting Ingot Using Na2SO35H2O

针对传统模铸钢锭内部出现的偏析、疏松及缩孔等质量问题,提出多芯复合浇铸大型钢锭工艺,实施了硫代硫酸钠模拟实验,测定了硫代硫酸钠熔体的凝固率,分析了芯坯数量对熔体凝固过程的影响。结果表明:在铸模内预置成分相同的低温芯坯可以促进熔体在芯坯表面的形核,增加熔体内部的"结晶雨",提高细小等轴晶的比例,显著缩短熔体的凝固时间。随着芯坯数量的增多,凝固过程中的"结晶雨"现象显著增加,凝固速度更快。

A multi-core composite casting process was proposed and simulated using Na2SO3 5H2O as melt to solve the problem of segregation, porosity and shrinkage in the traditional ingot. The solidification percentage of sodium thiosulfate melt was determined and the effect of core number on solidification was discussed. The results show that the preset cores r in the mould can improve the nucleation on the surface of cores, increase the dendrite rain in melt, raise the proportion of fine equiaxed grains and decrease greatly the solidification time of the melt. With an increase of core number, the dendrite rain rises significantly, solidification rate is faster and the solidification structure is finer and more compact.