低温正火工艺对球墨铸铁显微组织的影响

Effect of Low Temperature Normalizing Process on Microstructure of Nodular Graphite Cast Iron

对球墨铸铁进行低温正火,研究了保温时间对球铁中石墨及基体组织的影响。结果表明,随着保温时间的延长,球状石墨的圆整度提高,保温2 h后,点状石墨基本全部溶解。基体中铁素体的破碎程度随着保温时间的延长而提高,珠光体数量增多,但保温时间超过2 h后,基体组织没有明显变化。

A series of low temperature normalizing process were carried out for nodular graphite cast iron. The effects ofholding time on graphite and matrix of nodular graphite cast iron were studied. The results show that with the increase ofholding time the roundness of nodular graphite is improved.A^er holding for 2 h, the point graphites dissolve completely.Thebreaking degree of ferrite in the matrix increases and pearlite increases with the prolonging of holding time. The matrix has noobvious change when the holding time is more than two hours.