【摘要】 作者用定向凝固技术研究了铸铁的灰白转变过程,证实铬的石墨化能力与硅大致相等而方向相反,铬的稳定碳化物的能力主要不是来自增大碳在铸铁中的溶解度,而是来自缩小两个共晶温度的间隔.根据定向凝固的数据,画出了铬对两个共晶温度影响的曲线.并用电子探针对铸铁共晶凝固组织的边界进行了研究,铬和硅两个元素在灰口组织中的偏析与在白口组织中的偏析方向相反.对关于铸铁灰白转变机理的几种理论进行了归纳,并介绍了碳在铁水中以碳质聚合物存在的理论.更多还原

【Abstract】 Using unidirectional solidification technique, the transitions of white to grey and grey to white in cast iron have been studied, confirmed that the graphitization ability of Chromium is about the same as Silicon but has a inverse direction. The carbide stabilizing ability of Chromium mainly attribute to its narrowing the interval between two eutectics. not to its increment of Carbon solubility in cast iron. According to unidirectional solidification data, two eutectic temperature curves were plotted as a function of Cr content. The boundry of solidified eutectic structure of cast iron was analyzed by electron microprobe, the segregaton of both Cr and Si in grey structure was inverse compare with that in white structure. Theories on the grey-white transition mechanism in cast iron have been summed up in this paper, and especially the theory of polymeric carbonaceous clusters in liquid cast iron was introduced.更多还原