在不同的最大拉应力作用下反复加载-卸载过程中,测量了45冷轧钢试件表面某确定点漏磁场随拉应力的变化关系。结果表明,当最大拉应力＜610 MPa时,磁感应强度随应力的变化关系为线性关系;当最大拉应力处于610 MPa与屈服点653 MPa之间时,磁感应强度随应力的关系为折线关系,并且折线极值点的位置由较小应力处迅速移向较大应力位置。当最大拉应力大于屈服点时,磁感应强度的变化量保持恒定,折线极值点的位置也保持不变。从而证实了可以通过磁信号的特征对试件的安全性做出评估。

The relationships of magnetization and stress at different maximum tensile stresses of 45 steel items were measured during loading and unloading. The results indicated that,when maximum tensile stresses smaller than 610MPa,the relationships of magnetization and stress are linearity,which may estimate loading condition of items. When the maximum tensile stresses is larger than 610 MPa and smaller than yield point of 653 MPa,the relationships of magnetization and stress have become fold line and the position of extremum of fold line rapidly increases to maximum. When the maximum tensile stresses are larger than yield point of 610 MPa,the change of magnetization with the stress and the position of extremum of bending line remains constant. It shows that the relationships of magnetization and stress have been obtained and the security estimate can be made for ferromagnetic items making use of magnetic signal.