基于磁扰动状态下Q235钢应力梯度的无损表征

The Q235 Steel Stress Gradient Nondestructive Characterization Based on the Magnetic Perturbation

基于电磁学原理的铁磁性材料应力无损检测,在工程实际中具有广阔的应用前景。本文根据对增量磁导率概念新的理解,提出了一种铁磁性材料在低频交变强磁场周期磁化状态下的高频交变弱磁场扰动磁化作用方式。通过提取一个强磁场磁化周期内的平均增量磁导率,对四点弯曲装置加载Q235钢所产生的纯弯曲状态下的应力梯度及沿着深度分布的磁弹性能总量进行了磁学无损表征。通过两组不同实验参数设置下的平行实验,验证了所提出的测试方法可以有效地检测加载条件下试件内部应力梯度及沿着深度分布的磁弹性能总量。两组实验结果均具有一般性,表明该检测方法具有可行性,并且具有一定的工程实际应用价值。

The stress nondestructive testing of ferromagnetic materials based on the electromagnetics principle has broad application prospects in engineering practice. By a new understanding of the incremental permeability concept, a perturbation magnetization method of ferromagnetic materials under the periodic magnetization process of a low-frequency strong magnetic field superimposed a high-frequency alternating weak magnetic field is proposed. By extracting the average incremental permeability during a magnetization period of the strong field, the stress gradient in pure bending state and the total amount of magneto-elastic energy distributed along the depth generated by a four-point bending device loaded with Q235 steel have been nondestructively characterized. Through two sets of parallel experiments under different parameter settings, it is verified that the proposed testing method can effectively detect the internal stress gradient of the specimen under loading conditions and the total amount of magneto-elastic energy distributed along the depth. The two sets of experimental results are general, indicating that the detection method is feasible, and has a certain practical value in engineering applications.