42CrMo锻轴超声检测缺陷形成原因分析

Analysis on the Causes of Defects in Ultrasonic Test of 42CrMo Forged Shafts

42CrMo锻轴在粗加工后进行UT检测时发现有严重超标缺陷。通过低倍试验、化学试验、电镜试验和金相试验等方法对其超标缺陷部位进行分析。结果表明:钢锭浇注过程中耐火材料脱落,未完全上浮,留存于钢锭靠近尾部端的芯部,从而形成孔洞类的夹渣。

The produced 42CrMo forged shaft has been found to have serious out-of-standard defects during UT inspection after rough machining.Through macroscopic test,chemical test,electron microscope test and metallographic test and other methods,the defect parts exceeding the standard have been analyzed.The results show that the refractory material falls off during the pouring of the ingot,and it does not float up completely,and remains in the core of the ingot near the tail end,so it forms slag inclusions like holes.