Metal magnetic memory testing for early damage assessment in ferromagnetic materials

来源期刊：中南大学学报(英文版)2005年第z2期

论文作者：董丽虹 徐滨士 董世运 陈群志 王愈涯 张蕾 王丹 尹大伟

文章页码：102 - 106

Key words：metal magnetic memory testing； ferromagnetic materials； magnetic leakage signals； early damage

Abstract: In order to investigate the physical mechanism of metal magnetic memory testing, both the influences of earth magnetic field and applied stress on magnetic domain structure were discussed. Static tension and fatigue tests for low carbon steel plate specimens were carried out on hydraulic servo testing machine of MTS810 type and magnetic signals were measured during the processes by the type of EMS-2003 instrument. The results indicate that the initial magnetic signals of specimens are different before loading. The magnetic signals curves are transformed from initial random to regular pattern due to the effect of two types of loads. However, the shape and distribution of magnetic signal curves in the elastic region are different from that of plastic region in tension test. While in fatigue test those magnetic signals curves corresponding to different cycles are similar. The H_p(y) value of magnetic signals on the fracture zone increases dramatically at the breaking transient time and positive-negative magnetic poles occur on the two parts of fracture zone.