Stress induced magnetic field abnormality
(1. Department of Mechanical Engineering,Tsinghua University, Beijing 100084, China;
2. Fundamental Industry Training Center,Tsinghua University, Beijing 100084, China)
2. Fundamental Industry Training Center,Tsinghua University, Beijing 100084, China)
Abstract: Residual stresses in ferromagnetic material affect the direction and structure of domains and generate magnetic field abnormality on the surface. In the formation of stress induced magnetic field, the influence of geomagnetic field is unclear. Residual stress specimen was produced by tight matching of a round ring and a peg. The magnetic fields of contrast specimens, which were produced in geomagnetic field or in shielding geomagnetic field, were inspected with 8mm lift-off. The results show that mean amplitude of magnetic field of the specimen produced in geomagnetic field is 0.85% larger than that of specimen produced in shielding geomagnetic field. So the formation of stress induced magnetic field abnormality above the surface of inspected ferromagnetic material geomagnetic field gives little contribution.
Key words: magnetic field abnormality; residual stress; geomagnetic field