X80管线钢凹坑-划痕缺陷的磁记忆检测研究

为了研究不同机械损伤类型的力磁耦合特性,设计了带凹坑和划痕缺陷的X80管线钢试样,通过静载拉伸试验,对比分析两种缺陷在不同载荷作用下的磁记忆信号特征。结果表明:凹坑缺陷处切向磁场强度出现峰值,梯度值过零点,磁记忆信号的畸变程度随载荷的增加而降低;划痕缺陷在初始状态未表现出磁信号异常,但随载荷的增加,其切向磁场分量的应力集中特征渐趋明显;两种缺陷处,切向磁场梯度的峰谷值差与试样的损伤程度存在近线性关系,但变化趋势相反,这一特征可为X80管线钢机械损伤程度的定量评估提供参考依据。

Magnetic Memory Test for Dent-Scratch Defect of X80 Pipeline Steel

To investigate the mechanical-magnetic coupling characteristics of different types of mechanical damage,X80 pipeline steel specimens with dent and scratch defects are designed.Through the static tension test,the magnetic memory signal characteristics of the defects under different loads are compared and analyzed.The results show that the tangential component of the magnetic field intensity exhibits a peak,and its gradient appears zero crossing point at the dent defect.With the increase of load,the abrupt change degree of magnetic memory signal decreases.The magnetic signal at the scratch defect shows no abnormal in the initial state,but with the increase of load,the stress concentration characteristics of the tangential magnetic field components become more and more obvious.It is found that the peak-valley difference of the tangential magnetic field gradient is nearly linear with the damage degree of the specimen,but the trends at the two defects are opposite.This characteristic can provide a reference for the quantitative evaluation of mechanical damage degree of X80 pipeline steel.