高压加热器热交换管远场涡流检测技术的实验研究

Experimental study on remote-field eddy-current test technique for heat-exchange tubes of HP heaters

高压加热器的热交换管束泄漏事故将影响到机组的安全、经济运行。利用远场涡流检测技术可发现高压加热器热交换管束的金属缺陷。为了对缺陷状况做出准确全面的评定, 解剖报废的高压加热器, 利用其管束材料制作热交换管、隔板对比试样, 通过以高性能的远场涡流检测仪在实验室做检测试验, 与真实缺陷管段进行比较验证。实验证明, 在最佳检测频率且检测位置无隔板时, 高性能的远场涡流检测仪能真实反映出缺陷的最大深度; 当缺陷位置有隔板时, 仪器检测显示出的缺陷结果将比真实缺陷小。

Leaking failures of the heat-exchange tube banks of HP heaters have adverse impact on the safe and economic operation of units,and remote-field eddy-current test technique may be used to discover metallic defects of these tube banks To make accurate and thorough evaluation on the defects,some heat-exchange tubes of a rejected HP heater were used as the sample for a laboratory contrast test,which used high-performance remote-field eddy-current tester to make comparison with tubes with actual defects Test results show that the high-performance remote-field eddy-current tester can reflect the maximum depth of a flaw at optimal test frequency and without any baffle at the test location;when there is a baffle at the spot,however,the result shown by the tester will be smaller than the actual flaw