基于磁记忆技术对含缺陷焊缝的疲劳试验

对含有不同隐形损伤的40Cr焊板进行射线检测、疲劳试验和正交磁记忆信号测量，探索试件在疲劳应力作用下磁记忆信号的变化特征。试验结果表明：单一测量方式下的磁特征值不能表征焊板在疲劳循环载荷下的变化特征，所得结论存在偶然性；研究发现，可用磁场矢量梯度积分特征和磁场矢量合成梯度特征来评价焊板的疲劳损伤过程，并建立了以磁场矢量梯度特征为损伤参量的疲劳损伤模型，从而可以对含有隐形损伤焊接构件的疲劳寿命进行定量评估，为金属磁记忆技术在焊接缺陷定量评价上的进一步研究提供参考依据。

Fatigue test of welds with defects based on magnetic memory technology

The ray detection, fatigue test and orthogonal magnetic memory signal measurement are performed on 40Cr welding plates containing different invisible damages, exploring the characteristics of magnetic memory signals under the fatigue stress. The experimental results are accidental because the magnetic characteristics under the single measurement method cannot characterize the variations of the weld plate under fatigue cyclic loading. The study found that the integral gradient feature of the magnetic field vector and the combined gradient feature of the magnetic field vector can be used to evaluate the fatigue damage process of the weld plate. The study also establishes a fatigue damage model with the gradient feature of magnetic vector as the damage parameter, so that the fatigue life of the welded component with invisible damage can be quantitatively evaluated. The study also provides reference for further research on metal magnetic memory technology in quantitative evaluation of welding defects.