Testing and Simulation of Folding Defects within Cold-drawn Thin Wall CuCrZr Alloy Tubes

Folding defects were found at the near surface of the ITER grad (IG) CuCrZr cold-drawn thin walled tubes used as heat sink of fusion devices and the causes were studied by optical microscope and a scanning electron microscope.By analyzing the attenuation of ultrasonic bottom echoes,the defects were successfully detected,and subsequent ultrasonic simulations proved this method to be reliable.The testing process of this kind of defects indicates that the non-destructive testing of the CuCrZr heat sink tubes by visual testing (VT) and eddy current testing (ECT) is not sufficient if without ultrasonic testing (UT).