石墨形状对铸铁熔凝层深的影响

Effects of graphite shape on the melted-depth of cast irons surface melted by plasma beam

利用等离子束对灰铸铁和球墨铸铁进行熔凝处理,探讨铸铁中石墨的形状对熔凝层深的影响。等离子束熔凝处理后,使用扫描电镜(SEM)和X射线衍射仪(XRD)对熔凝层的形貌和组织进行分析。在SEM图片上测量熔凝层深。熔凝试样的截面硬度分布也显示出熔凝层的大概层深。结果表明,熔凝层的硬度相对于基体来说有很大的提高。在同样的等离子束工艺参数的条件下,灰铸铁的熔凝层深小于球墨铸铁的熔凝层深,主要原因是灰铸铁的导热率大于球墨铸铁的导热率。

Gray cast iron(GCI) and nodular cast iron(NCI) were subjected to melting by plasma beam to investigate the effects of graphite shape on the melted - depth.Through the systematic physical characterization including scanning electron microscope(SEM) and X - ray diffraction(XRD),the morphology and structures of the specimens were analyzed.The depth of melted zone(MZ) was measured on the SEM photograph.And the melteddepth was also shown in microhardness profile of the cross - section.The microhardness of the cast irons was found to be significantly increased after melting by plasma beam.The melted - depth of NCI was deeper than that of GCI. The main reason was that the GCI with flake graphite had a higher thermal conductivity than that of the NCI with spheroidal graphite.