预埋穿线消磁套管在磁粉探伤时将预埋穿线消磁套管磁化；当预埋穿线消磁套管的长轴与地磁方向一致并受到冲击或振动载荷时被地磁场磁化；预埋穿线消磁套管磨削、电弧焊接、低频加热及强磁体接触被磁化等。只有在个别情况下预埋穿线消磁套管上的剩磁有用处，但在绝大多数情况下，其上的剩磁都是有害的，故进行退磁，退磁就是将预埋穿线消磁套管内的剩磁减小到不妨碍使用的程度。

Magnetizing the workpiece during magnetic particle inspection; When the long axis of the workpiece coincides with the geomagnetic direction and is subjected to impact or vibration load, the workpiece is magnetized by the geomagnetic field; Workpiece grinding, arc welding, low frequency heating and magnetizing of strong magnet contact etc. The remanence on the workpiece is useful only in a few cases, but in most cases, the remanence on the workpiece is harmful, so demagnetization is to reduce the remanence in the workpiece to a level that does not hinder the use.

技术参数（Technical parameter）

移动行程：1200mm;

Movement stroke: 1200mm;

输入电压：380V 50Hz；

Input voltage: 380V 50Hz

输入电流：200A；

Input current: 200A

线圈截面：150-1100mm

Coil section: 150-1100mm

整机绝缘电阻大于2兆欧；

The insulation resistance of the whole machine is greater than 2 megohms.

退磁效果：预埋穿线消磁套管退磁后部分剩磁不大于0.2mT；

Demagnetization effect: the remanence of the workpiece after demagnetization is not more than 0.2mT