U形管弯管段消应力热处理过渡区的异常涡流信号

The abnormal eddy current signal after stress relief heat treatment of U-tube

摘要: U形传热管在制造过程中常采用电极加热的热处理方法对弯管段进行消应力热处理，热处理后需要使用内穿式探头对U形管进行涡流检测，信号分析时发现在电极夹钳位置，即热过渡区存在一个异常信号。通过多种无损检测方法的辅助检测，并采用整体再次固溶热处理的方式验证了该信号并不是缺陷信号，而是一种固有的工艺加工信号。

Abstract: During the manufacturing process of U-tube, the method of electrode heating heat treatment is often used to conduct stress-relieving heat treatment on the section of U-tube. After the heat treatment, the U-shaped pipe needs to be subjected to eddy current detection in the bend. During the signal analysis, it is found that there is an abnormal signal at the position of electrode clamp, that is, the thermal transition zone. It is verified that the signal is not due to a discontinuous signal, but is produced by an inherent processing signalas confimed by other non-destructive testing methods.