【摘要】 <正> 一、前言对铸铁结晶过程的研究已有较长的历史了,特别是对铸铁中石墨从一种形态到另一种形态的变化虽然已进行了多方面的研究。但是,对石墨长大的机理仍存在这样和那样的分岐认识。六十年代对球状石墨的形成过程进行过热烈的争论。近年米对蠕虫状石墨的形成和长大方式的讨论也是一个引人注目的内容,在这个问题上也存在着一些不同的认识最近对于蠕化率在描写蠕虫状石墨生长过程中的不同行为的作用也有了进一步认识。对于初生片状石墨目前认为有两种类型,更多还原

【Abstract】 In present paper, the centrifugal method has been employed for studying the mophology of primary graphite in hypereutectic ductile, compacted and gray irons. The results demonstrate that the primary graphite in ductile iron is spheriodal; in the compacted graphite iron treated with rare earth the mophology of the primary graphite varies according to the percentage of compacted graphite particles existing in the structure. With high percentage of compacted graphite particles the early stage mophology of primary compacted graphitc is "insect-like", whereas it appears spheroidal and to have an explosive mophology when the percentage of compacted graphite particles is low; and in gray iron the primary graphite grows from a neucleus and radially outward. It could be concluded that even though the tyde C graphite observed under optical microscope is different from type F, there is no substantial difference between them and they have similar mophology in three dimentional space.更多还原