ERW管焊缝缺陷漏磁检测方法可行性分析

The Feasibility Analysis of MFL Method for ERW Tube

介绍了现有由轴向磁化和周向磁化检测技术组合构成的相对螺旋扫查式钢管漏磁检测方法,分析了该方法对ERW管焊缝缺陷检测的困难所在:相对螺旋扫查方式所形成的周期性焊缝信号掩盖了其上的缺陷信号,并且在漏磁叠加场的根源上难以区分.针对此问题,提出一种单一轴向磁化下的轴向直线扫查式ERW管焊缝漏磁检测方法,并通过实验和有限元法对其可行性进行了论证分析,在发现单一轴向磁化下钢管纵向伤可形成漏磁场并被观察出的基础上,对ERW管焊缝上最难以检出的人工纵向伤进行检测试验,最终表明:ERW管焊缝缺陷在单一轴向磁化下的漏磁检测方法具有可行性.

The present MFL method which consists of axial magnetization and circumferential magnetization technology and accomplishes its detection by relative helical scanning is presented. Afterwards, the difficulty of inspection for the defects in ERW tube welding is analyzed. The main reason is that the helical scanning approach causes periodic signals and submerges the signals of the defects in welding. Additionally, for the problem, an axial scanning method for ERW tube welding under a unidirectional axial magnetization is proposed. As a result, the feasibility of the proposed method is verified by experiments and the finite element method, and it is found that the MFL from longitudinal defects can be produced and detected clearly. Further, detection experiments for ERW tube welding indicate that the MFL method for ERW tube defects under a unidirectional axial magnetization has its feasibility and practicality.