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进入七十年代以来,稀土在冶金工业上的用量迅速增加,占稀土总销售量的35～50％。稀土及其合金除用于炼钢方面外,用作球化剂及变质剂炼制球墨铸铁和高强度灰口铸铁所获得的经济和技术效果是显著而肯定的。目前世界球墨铸铁产量大约600～800万吨,我国约40～60万吨。阻碍球墨铸铁扩大产量和广泛使用的原因之一是厚大断面或超厚大断面的球铁件在球化处理时产生球化衰退,使性能降低。因此,球化衰退不仅是需要解决的理论问题,而更是需要解决的实际问题。
Since the 1970s, the amount of rare earths used in the metallurgical industry has rapidly increased, accounting for 35% to 50% of the total sales of rare earths. In addition to the rare earth and its alloys used in steelmaking, the economic and technical effects of ductile iron and high-strength gray cast iron used as a nodulizer and modifier are significant and affirmative. At present, the output of ductile iron in the world is about 600-800 million tons and about 40-60 million tons in our country. One of the reasons that prevent the ductile cast iron from expanding production and being widely used is that the ductile iron pieces with thick sections or over-thick sections have a spheroidizing recession during the spheroidizing treatment and the performance is reduced. Therefore, the decline of globalization is not only a theoretical problem to be solved, but also a practical one that needs to be solved.