带防腐层在役压力容器表面磁粉探伤灵敏度的试验研究

Experimental Study on Sensitivity of Magnetic Probe for In-service Pressure Vessel Coated with Anti-Corrosive Layer

采用人工裂纹试样的方法 ,模拟压力容器涂刷油漆防腐层的状况进行磁粉探伤 ,得出了油漆防腐层厚度与裂纹检出灵敏度的定量关系 ;结合CVDA《压力容器缺陷评定》规范 ,探讨了试验方法对一般在役压力容器带有油漆的情况下 ,进行磁粉探伤检验的可行性。研究表明 :采用交流磁化法进行探伤 ,当漆层厚度大约小于2 5 0 μm时 ,灵敏度影响较小 ,同时亦表明不宜使用直流磁化方法。该结论对承受低应力工况条件下的压力容器安全质量检验和评估 。

By means of artificial crack sampling method, magnetic probe is simulated on the pressure container coated with anti corrosive paint layer. The quantitative relationship between the thickness of the anti corrosive paint and the sensitivity of the probe is obtained. According to CVDA'Pressure Container Defect Evaluation'norms, the feasibility of magnetic probe for the in service pressure container with paint coating is discussed. The result indicates that when the thickness of the paint layer is less then 250μm, the sensitivity of magnetic probe is hardly affected by AC yoke method, however, DC yoke method is not feasible. This conclusion is valuable to the quality test and safety evaluation of the pressure vessel enduring lower stress.