拉应力对不同厚度Q345钢磁记忆信号的影响

为明确磁记忆信号与拉应力之间的对应关系和几何尺寸对试件表面磁场的影响,对Q345低合金钢不同厚度板状试件进行静载拉伸实验.利用TSC-1M-4型磁检测仪,研究3种厚度的光滑试件表面磁记忆信号在不同拉应力下的变化规律.结果表明:弹性阶段磁记忆信号与拉应力之间有较好的相关性,塑性阶段两者相关性较弱;切向磁记忆信号对试件局部屈服的表征比法向磁记忆信号更敏感,利用切向磁场的畸变性可预判试件的早期塑性变形和应力集中区;同一应力水平下,试件表面磁场强度随厚度增加而减小,但不影响其变化规律.

Influence of tensile stress on magnetic memory signal in Q345 steel with different thicknesses

To determine the relationship between magnetic memory signal and tensile stress and the influence of geometric size of the specimen on the surface magnetic field, static tensile tests on plate specimens made of Q345 low alloy steel with different thicknesses were performed. The variation regularities of surface magnetic signals of specimens with three thicknesses under different tensile stresses were investigated using the magnetometer TSC-1M-4. The test results show that the magnetic memory signal is positively correlated with tensile stress in the elastic stage but weakly correlated in the plastic stage. Compared with the normal component, the tangential component is more sensitive in characterizing the local yielding of the specimen. The early plastic deformation and stress concentration zone can be predicted via the abnormal magnetic change of the tangential component. Under the same stress level, the specimen thickness has a negative correlation with the surface magnetic intensity and no influence on the variation trend.