不锈钢管内壁腐蚀层厚度的涡流检测仿真

针对耐热奥氏体不锈钢内壁腐蚀层厚度测量难的问题,建立了典型腐蚀状态下奥氏体不锈钢结构的有限元仿真模型,提出了采用低频涡流检测内壁腐蚀层厚度,并用高频涡流测量外壁氧化层厚度以对低频检测结果进行修正的检测方法.结果表明,腐蚀层厚度增加会引起低频涡流检测信号幅值和阻抗模的增加,而外壁存在的氧化层会对检测信号造成干扰.腐蚀层厚度和氧化层厚度对涡流检测信号影响的变化规律与仿真结果具有一致性.

Simulation of eddy current detection for corrosion layer thickness on inner wall of stainless steel tube

Aiming at the difficult measurement of corrosion layer thickness on the inner wall of heat-resistant austenitic stainless steel, a finite element simulation model for austenitic stainless steel structure under typical corrosion conditions was established. For the modification of low frequency detection results, a detection method using low frequency eddy current to measure the thickness of corrosion layer on the inner wall but high frequency eddy current to measure the thickness of oxide layer on the outer wall was proposed. The results show that the increasing thickness of corrosion layer will cause the increase of both amplitudes and impedance modes of detection signals using low frequency eddy current, while the existence of oxide layer on outer wall will cause interferences to detection signals. The variation rule of the influence of corrosion and oxide layer thicknesses on the eddy current detection signals is consistent with simulation results.