大型船用曲臂锻件锻后热处理后进行冲击试验, 发现曲臂左侧端部比右侧端部的冲击功低, 不符合技术要求。通过化学成分分析、断口试验、金相检验和能谱分析等方法, 对该锻件冲击功偏低的原因进行了分析。结果表明: 曲臂锻件的正火温度偏高且加热不均匀, 致使曲臂左侧端部的晶粒粗大, 同时材料中含有较多的夹杂物, 导致了该区域的冲击功偏低。

The impacting energy of left side area of a crank throw forging for large ship after forging heat treatment was lower than that of the right area, and it didn’t met the technical requirement. By means of chemical compositions analysis, fracture test, metallographic examination and energy spectrum analysis, The reasons of the low impact energy was analyzed. The results show that because the normalizing temperature was higher and non-uniform, the grain of left side area of the crank throw grew up, and this was the main reason for the lower impacting energy. At the same time, there were a lot of inclusions in material of the crank throw, which also could reduce the impacting properties of the crank throw.