呋喃树脂砂型球铁铸件异常组织分析

采用呋喃树脂砂型铸造球铁件时，由于树脂和硬化剂分解产生的C,S渗入铁液使铸件表层局部区域形成大量密集的细片状和点状过冷石墨，这些区域加工表面上呈灰暗色。在容易产生这种缺陷的部位设置冷铁．使该部位不与树脂砂接触，因而能避免上述缺陷产生。

Abnormal Structure Analysis of Ductile Iron Castings Produce with Furan Resin Sand Moulds

when producing ductile castings with furan resin sand, the C and S resulted from decomposition of resin and catalyst penetrated into molten iron and caused large quantities of fine flake and dot-shaped supercooling graphites in some areas of the casting which are appearing as dark color defects on the machined surfaces. By setting chills on the defect locations to isolate the molten iron in those areas from contact with the resin sand, the defects were successfully avoided.