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本文就常见的稀土镁球铁铸造、热处理缺陷作一简要分析,供参考。铸造缺陷一、球化不良、球化衰退和孕育衰退: 1.球化不良:是球化剂加入量过少或吸收率低、原铁水硫量高,引起铸件球化甚差或根本不球化。特征:宏观断口,在银灰色断口上夹有分布较均匀的小黑点,通常叫做芝麻点。球化愈差,黑点的面积随之增大,数量也愈多,分布愈密集。不球化时,断口似灰口铸铁。机械性能随球化不良的程度而下降;微观特征:除球状、团状石墨外,在黑点处有分散到
In this paper, rare earth magnesium iron castings, heat treatment defects for a brief analysis, for reference. Casting defects First, bad ball, ball recession and pregnancy recession: 1. Bad ball: the nodulizer is added too little or low absorption rate, the original high-sulfur molten iron, causing the cast ball is very poor or not at all The Features: Macroscopic fracture, the distribution of silver gray fracture is more evenly distributed black spots, commonly known as sesame seeds. The poorer the spheroidization, the larger the area of the black spots, the greater the number and the more dense the distribution. No ball, the fracture seems gray cast iron. Mechanical properties decline with the extent of poor spheroidization; microscopic features: In addition to ball-shaped, group-like graphite, scattered at the black spots