不同初始磁状态U75V钢变形阶段的磁记忆参数表征

通过对经退磁处理和未消磁的U75V钢光滑试件进行静载拉伸试验研究了初始磁状态对试件表面磁信号的影响。结果表明:消磁试件长度范围内的表面磁场在弹性阶段呈现很好的线性分布。进入塑性后,切向磁场出现局部弯曲。利用切向磁场均值和法向磁场斜率变化可以区分弹塑性阶段以及确定弹性阶段的应力幅值;未消磁试件随着载荷增加其表面磁场波动幅度减小,由初始无规律分布逐渐转向磁有序状态。利用未消磁试件长度范围外的磁记忆信号曲线的磁场均值及斜率变化可以有效表征不同的变形阶段。

Characterization of Magnetic Memory Parameters of U75V Steel with Different Deformation Stages and Initial Remanent States

Influence of initial remanent states on metal magnetic memory (MMM) signals was investigated by performing static tensile tests on the demagnetized and undemagnetized U75V steel specimens.For the demagnetized specimen,the surface magnetic fields present a good linearity within its longitudinal axis in the elastic stage,and the tangential magnetic component shows an obvious local bending in the plastic stage.The average magnetic field of the tangential component and the magnetic gradient of the normal component can be used to differentiate the elastic-plastic deformation stages and evaluate the elastic stress.For the undemagnetized specimen,the amplitude of magnetic field variation reduces with increasing load,and the magnetic signals transform from initial random distribution to magnetic ordering state.The deformation stages can be characterized by both the average magnetic field and the magnetic gradient of MMM signals measured outside the longitudinal axis of the undemagnetized specimen.