为了能够利用磁记忆曲线对试件的应力状态进行评估, 加工了Q235钢缺陷非对称试件。研究了在循环拉伸应力下, 其在在线加载、在线卸载和离线卸载三种不同状态下的磁记忆特征。结果表明, 弹性范围内三种状态下磁场强度曲线与初始曲线明显不同, 在整个弹性范围内各自保持自己的形状趋于稳定; 进入屈服阶段之后, 在线加载和在线卸载曲线开始在缺陷位置出现波峰波谷; 进入颈缩阶段后, 在线卸载曲线出现了大的跳跃。可见, 通过磁记忆曲线对试件的受力状态进行评估是可行的。

To evaluate the stress states of the components by the magnetic memory signal, Q235 steel defect asymmetrical samples were made. The characteristics of magnetic memory of Q235 steel in the three different states which are online-loading, online-unloading and offline-unloading under circle tensile stress have been studied. The results show that magnetic memory signals have different characteristics under different states. The curves in elastic range are different form that of initial stage and the curves of three states keep their shape on the whole elastic range respectively. In yielding stage, the curves of online-loading and online-unloading are beginning to appear wave peak and wave valley at the defect position. On the verge of necking, the curves of online-unloading appear a jump. From elastic range to necking, the curves of offline-unloading have no obvious change till fracture. It is feasible to preliminarily evaluate the stress state by the magnetic memory signal.