400-18LT球墨铸铁的韧脆转变温度检测方法研究

Investigation on Detection Method for Ductile-brittle Transition Temperature of 400-18LT Ductile Iron

研究了-130~0℃下400-18LT低温球墨铸铁低温冲击性能,计算出QT400-18AL冲击功随温度变化曲线,随冲击温度的降低,冲击功逐渐降低,在-74.3℃达到韧脆转变温度点。用ZESS-18扫描显微镜观察了不同冲击温度下断口形貌,根据冲击断口测量晶状区断面率,根据晶状区断面率随温度变化曲线拟合出韧脆转变温度为-72.4℃。两者的测试结果是吻合的。

The low temperature impact property of QT400-18 LT was investigated and its impact energy varies with temperature was calculated. The result show that with the decline of impact temperature, the impact energy decreases and the ductile-brittle transition temperature point is-74.3 ℃. The ZESS-18 SEM was applied to observe impact fracture morphology, and the crystalline zone section rate was tested, the ductile-brittle transition temperature was-72.4 ℃according to crystalline zone section curve with temperature increasing. The tested ductile-brittle temperature from two methods was nearly identical.