传统的曲轴淬火层深度测试方法是金相抽检，不能满足汽车工业生产需要。因此，采用超声散射回波法对康明斯曲轴淬火层深度进行检测。实验室和现场检测结果表明，超声无损检测可取代有损的金相试验法测量曲轴淬火层深度，测量误差≤0.3 mm。

Sampling examination by metallographic test was the traditional method for measuring the depth of the quenched layer in crankshaft, which could not meet the needs of the production of auto industry. Ultrasonic scattering echo method was used to measure the depth of the quenched layer in Commins crankshaft. It was showed by laboratory and on-site tests that ultrasonic nondestructive testing could be applied to the measurement as a substitute for metallographic examination. The measuring error was ≤0.3 mm.