核电站蒸汽发生器用690镍基合金传热管制造过程中的涡流检测

Eddy current testing in the manufacture of 690 Ni-base alloy heat transfer tubes for nuclear power plant steam generator

核电站蒸汽发生器用690镍基合金传热管在制造过程中至少需进行3次涡流检测,第一次是直管成品时,使用外穿式探头主要检测传热管外壁缺陷;第二次是弯管前,使用内穿式探头主要控制传热管信噪比;第三次是弯管后,使用内穿式探头主要检测传热管内壁缺陷。介绍了3次涡流检测的时机、目的、参数设置、信号分析和验收评定结果。另外通过试验研究了整体消应力热处理对涡流检测的影响,试验结果表明,整体消应力热处理对U形传热管的内涡流检测信号无影响且未产生热处理信号。

At least three times of eddy current tests are required during the manufacture of 690 Ni-base alloy heat transfer tubes used in nuclear power plant steam generator. The initial eddy current test is mainly to detect the outer surface defects of the heat transfer tube in the case of straight pipe, and the second time one takes place before bending the tube and employs the inner pass-through probe to control the SNR of the heat transfer tube inner eddy current signals. The final one takes place after bending the tube and is mainly to detect the inner wall defects of the heat transfer tube by inner pass-through eddy current probe. This paper introduces the opportunity, purpose, parameter setting, signal analysis and acceptance evaluation of three eddy current tests. In addition, the effect of integral stress relief heat treatment on eddy current test is studied by experimental comparison. The results show that the integral stress relief heat treatment has no effect on the inner eddy current signal of U-shaped heat transfer tubes.