RE对耐候钢溶质再分配的影响

Effects of RE on Solute Redistribution of Weather-Resisting Steel

为研究RE对耐候钢中各元素偏析的影响,进行了不同RE含量的耐候钢定向凝固实验,拉速为15μm.s-1,观察了RE对耐候钢定向凝固试样糊状区的影响,并用电子探针定量分析了耐候钢中各元素的溶质分配系数。结果表明,钢中加入RE可以抑制枝晶生长,细化枝晶,有利于二次枝晶的生长,可以促进等轴晶的生成。RE原子在晶界的富集可以抑制溶质元素在固液界面的析出,提高各元素的非平衡溶质分配系数,可以有效减轻耐候钢的宏观偏析。

The direction solidification experiment of different RE contents in weather-resisting steel was carried out,and aimed to study the effect of RE on macrosegregation of weather-resisting steel.The pulling rate was set to 15 μm·s-1 in the course of the experiment.The effect of RE on pasty area of direction solidification sample of weather-resisting steel was observed and non-equilibrium solute distribution coefficient of different elements in weather-resisting steel was analyzed quantitatively with detecting probe.The results indicated that the mixing of RE into the steel might inhibit the growth of treelike crystal and get the result of thinning the treelike crystal,thereby in favor of the growth of secondary treelike crystal,and furthermore,it might promote the growth of equiaxed crystal.The enrichment of RE atom at grain boundary might inhibit the precipitation from solid liquid interface of solute element,increase non-equilibrium solute distribution coefficient of various elements and reduce the macrosegregation of elements in steel.