镁在球墨铸铁中分布状况的研究

Study on the Distribution of Magnesium in the Ductile Iron

掌握镁在球墨铸铁件中的分布状况将有利于指导球墨铸铁的生产,同时对于了解石墨球化的机理也有着一定的参考价值。实验结果表明,镁在球墨铸铁件表面大量富集,在整个横截面上由外到内呈梯度分布状态。在对这一结果进行充分讨论与分析的基础上,提出球墨铸铁液中的气泡在挤压力作用下的双向迁移造成了镁分布的不均匀,这种挤压力来源于由温度下降引起的体积收缩及球墨铸铁液中的石墨化膨胀。

Magnesium is the main elements to obtain the spherical graphite,and getting clear distribution of magnesium will help guide the production of ductile iron and has certain reference value to understand the mechanism of graphite nodularization.Experimental result shows that the surface of ductile iron casting has a large amount of magnesium,and,there is a gradient distribution of magnesium from external to internal in the cross section.On the basis of fully discussing and analyzing,this paper points out that the heterogeneous distribution of magnesium is caused by the bilateral migration of the bubbles in the molten metal,and,the bubbles migration is caused by the extrusion force which was caused from the volume shrinkage of the liquid metal and the graphite expansion.