地磁场激励下残余应力分布的磁检测方法

Magnetic testing method of residual stress distribution by geomagnetic excitation

为实现铁磁材料内部应力分布的无损评估,在地磁场激励条件下,将ASTM1020钢Y型坡口焊缝试样水平放置,通过测量试样表面上方10mm处磁感应强度垂直分量的分布,得到了试样热影响区的应力分布。试样应力分布磁测量结果同盲孔法应力分布测量结果具有较好的一致性,说明在不用人工磁化场磁化材料的情况下,仅依靠地磁场激励就可以通过磁检测方法获得材料内部应力的分布情况。

Magnetic testing was used for nondestructive evaluation of stress distributions inside ferromagnetic materials. For the testing a steel ASTM1020 specimen with a Yshaped welding line was positioned horizontally by geomagnetic excitation with a sensor 10 mm above the specimen to measure the normal component of the magnetic induction. The distribution of the stress inside the specimen can be calculated from the normal component of the magnetic induction intensity. The stress distribution measured by the magnetic testing is identical to that measured with small hole stress testing indicating that the stress distribution in ferromagnetic materials can be reliably measured by magnetic testing with geomagnetic excitation without a strong artificial magnetizing field.