某批42CrMo钢轮毂锻件在进行超声波探伤检验时发现有密集型缺陷, 导致锻件报废。通过低倍检验、金相检验以及扫描电镜分析等试验, 对该轮毂锻件超声波探伤缺陷性质及产生原因进行了分析。结果表明：该42CrMo钢轮毂锻件超声波探伤缺陷性质为白点裂纹; 其是在钢中氢和正火冷却应力共同作用下产生的; 建议锻件在锻后避免直接空冷, 且应进行去氢热处理。

The intensive flaws were found in a batch of 42CrMo steel hub forgings when ultrasonic inspecting, which resulted in the scrap of the forgings. By means of macrostructure examination, metallographic examination and scanning electron microscope analysis, the properties and causes of the ultrasonic inspection flaws of the hub forgings were analyzed. The results show that the ultrasonic inspection flaws were flake cracks which formed under the coactions of hydrogen and normalizing cooling stress. It was suggested that the forgings should avoid direct air cooling after forging, and should be treated by dehydrogenation heat treatment too.