针对铁磁性承压设备脉冲涡流热成像(ECPT)缺陷检测过程中,拉应力对铁磁材料磁导率的影响被忽略而引起的缺陷量化精度不高的问题,结合力磁耦合关系、电磁感应定律、焦耳定律仿真探究弹性拉应力对ECPT量化不同方向、不同深度缺陷的影响。结果表明,不同方向缺陷的最大磁导率随着弹性拉应力的增加而增加,同一应力作用下,缺陷处的最大磁导率随着横向缺陷深度的增加而增加,但最大磁导率对竖直缺陷深度的变化不敏感;在ECPT缺陷量化过程中,基于温差特征的横向缺陷的深度量化曲线的斜率随应力的增加而增加,且横向缺陷深度量化拟合曲线的标准差低于0.3 ℃,可决系数达95%,拟合效果好;基于温差特征的竖直缺陷深度量化曲线受应力的影响较小。

Aiming at the problem of low defect quantification accuracy caused by the neglect of the effect of tensile stress on the permeability of ferromagnetic materials in the process of defect detection of ferromagnetic pressure equipment by eddy current pulsed thermography (ECPT), this paper combines the force-magnetic coupling relationship, electromagnetic induction law and Joule's law to simulatively investigate the influence of elastic tensile stress on defect quantification in different directions and depths by ECPT. The results show that the maximum permeability of the defects with different orientations increases with the elastic tensile stress growing. The maximum permeability at defect increases with the depth of the horizontal direction of defect. Meanwhile, it is not sensitive to the change of the depth of the vertical direction of defect. In the process of ECPT defect quantification, the slope of the horizontal defect depth quantification curve based on the temperature difference increases with the stress. The standard deviation of the horizontal defect quantification fitting curve is lower than 0. 3 ℃ and the coefficient of determination is higher than 95%. As a result, the fitting effect is good. The vertical defect depth quantification curve based on temperature difference characteristics is less affected by stress.