球状石墨的形核与孕育--球墨铸铁基础理论的最新发展(一)

石墨球的形成分两个阶段：形核与生长。虽然形核不影响最终的形状，但它是石墨球形成的重要过程。石墨的形核物质有石墨、硫化物、氧化物、碳化物、氮化物、金属间化合物及气体。各种物质的形核机制可以不同，但是都必须符合晶格匹配关系（失配度小于6%时，形核能力强），以及满足相互的界面能要求。由于球铁过冷倾向大，所以孕育是球铁生产的必须工序。鉴于硫氧化物是球墨形核的重要组分，特介绍一种新型高效孕育剂，其特点在于孕育剂中含有一定的硫氧非金属物质，可补充球化处理后铁液硫、氧的贫缺。

Nucleation of Spheroidal Graphite and Inoculation--Recent Development of The Basic Theory of Spheroidal Graphite Cast Iron(Ⅰ)

The formation process of the spheroidal graphite can be divided into two stages:nucleation and growth.Though the nucleation doesn't determine the final shape of the graphite,it is an im-portant stage of the graphite spheroid formation.The materials which can be the nuclei for the graphite formation include:graphite,sulphide,oxide,carbide,nitride,intermetallic compound and gas. The nucleation mech anisms of various materials may be different,however,they must be accord with the matching relationship of the crystal lattices (the nucleation capacity is powerful when the mis-matching degree is less than6%)and meet the requirement of interface energy between each other.On account of the high supercooling tendency of the s.g.iron,the inoculation treatment is a must op-eration of s.g.iron production.Considering that the sulphide and oxide are the important ingredient of spheroidal graphite nucleation,a new type of high-efficient inoculant was recomended.As its feature,the inoculant contains some sulphide-oxide of non-metallic materials which would make up the de-ficiency of sulphur and oxygen in molten iron after spheroidalizing treatment.