拉应力对45钢磁滞与磁致伸缩曲线的影响规律

Effect of tensile stress on the magnetic hysteresis and magnetostriction curves of 45 steel

针对弱磁致伸缩特性(峰值应变约十几微应变)的碳钢材料,集成微型拉伸装置、高精度电阻应变仪、交流磁化器和磁测量模块,构建单轴拉伸状态下材料磁滞和磁致伸缩曲线的同步测量系统,实验测试拉应力对45号钢材料磁滞与磁致伸缩曲线的影响规律。结果表明:随拉应力增加,特征参量矫顽力(Hc)、磁致伸缩最大值(λMAX)呈指数下降趋势,饱和磁感应强度(Bs)近乎线性降低;磁参量剩余磁感应强度(Br)、最大磁导率(μmax)和磁致伸缩曲线下极值位置(Hcλ)均呈现先快速增长后缓慢下降的两阶段变化规律,与应力的关系均服从三次多项式方程。标定得到的上述特征参量与应力的关系方程,可用于应力无损表征,从表征能力和测试系统的工程应用性角度对比讨论基于磁滞与磁致伸缩曲线的应力检测方法的特点。

To achieve synchronous measurement of magnetic hysteresis loops and magnetostriction curves of low-magnetostriction materials under uniaxial tension,an experimental system was constructed by integrating micro-tensile device,high-precision strain gauge,AC magnetizer and magnetic measurement module.The effect of tensile stress on the magnetic hysteresis loop and magnetostriction curves of 45 steel was investigated.The results show that with the increase of elastic tensile stress,the feature parameters of coercivity(Hc),maximum magnetostriction(λMAX)demonstrate exponential decreasing trend,the saturation magnetic induction intensity(Bs)linearly decreases while the magnetic remanence(Br),maximum permeability(μmax)and position of the lowest extremum of the magnetostriction curve(Hcλ)exhibit two-stage trend with an initially rapid growth followed by slow decline.The dependency of Br orμmax or Hcλon the tensile stress can be described by cubic polynomial equation.The obtained calibration equations can be used for tensile stress characterization.The characterization accuracy and applicability of testing system are compared between the magnetic hysteresis loop and magnetostriction curve based methods for stress measurement.