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研究了Sr对高铬铸铁的变质作用。结果表明,向高铬铸铁中加入微量Sr可有效改善高铬铸铁的铸态组织,使碳化物变的细小均匀。变质后高铬铸铁中的碳化物形貌发生显著变化,共晶碳化物由原来粗大的板片状转变为细小的圆杆状或圆管状,并且其横截面直径大部分在亚微米级。这些细小的碳化物在基体上均匀分布,而且碳化物与基体组成的共晶团得到明显细化;但是过量Sr会使变质效果急剧衰退,这表明Sr的变质效果存在明显的过变质现象。
The metamorphism of Sr on high chromium cast iron was studied. The results show that the addition of trace amount of Sr to high chromium cast iron can effectively improve the as-cast microstructure of high chromium cast iron so that the carbides become small and uniform. The morphology of carbides in the high chromium cast iron changed significantly after metamorphism. The eutectic carbides changed from the coarse plate-like shape to the small round rod shape or round tube shape, and the cross-sectional diameter was mostly in the submicron order. These fine carbides are uniformly distributed on the matrix, and the eutectic composition of the carbide and the matrix is obviously refined. However, excessive Sr deteriorates the metamorphic effect sharply, indicating that the metamorphism of Sr is obviously over-metamorphic.