不同检测环境下磁记忆信号变化研究

通过开展中碳45#钢试件的静载拉伸实验，采用磁记忆检测技术，研究了在线及离线2种检测环境下、不同加载阶段试件磁信号变化情况。结果显示：对应不同的检测环境，检测得到的试件磁信号差别显著。在线检测时试件周围磁环境对检测准确性影响较大，磁记忆检测判据——“过零点”失去作用；离线检测时检测效果良好，过零点能够反映试件应力集中部位。同时，对实验过程中的磁场强度变化及过零点漂移现象进行了理论分析。

Change of Magnetic Memory Signals Under Different Testing Environments

The experiment of the static tension for medium carbon 45^# steel was done . The magnetic signal changes of specimens under different loading phases and testing environments were studied by use of the technology of magnetic memory testing. The results indicate that the magnetic signals of specimens have obvious difference under two kinds of testing environments. In the case of on-line testing, the testing precision is strongly influenced by the magnetic environment around the specimen, and the point of cross-zero regarded as the criterion of magnetic memory testing is insignificant. In the case of off-line testing, the effect is good, and the stress concentration areas of specimens can be character- ized by the point of cross-zero. Furthermore, the variation of magnetic field strength and the phenomenon of the excursion of the cross-zero point appeared in experimental processes were analyzed.