稀土对铸态球铁显微组织的影响

Influence of Rare Earth on Microstructure of as-cast Ductile cast Iron

随球化剂加入不同量的稀土，处理合硫量不同的铁水，浇注阶梯试块，对全相组织分析表明；少量稀土增加石墨球数，减少铸态碳化物；超过一定量后，稀土特使碳化物量增加，最佳稀土加入量与原铁水含硫量有关．对于薄壁铸件及低硫原铁水，稀土的这种作用更明显，且其适宜的加入量范围更窄．

The influences of RE on microstructure fo as-cast ductile iron with different sulfur content of base melt have been strdied.It is shown that the addition of small amount of RE promotes high nodule counts and prevents the occurrence of carbides ,and carbides reappears when RE addied in excess of optimum range.Rhe optimum range of RE is related to the base sulfur content.When base sulfur content is low and section thickness of casting is thin ,the effect of RE is more pronounced and the optimun range fo RE is narrower.