1概述国内外大量球罐破坏事故的分析结果表明,导致球罐失效脆断的直接原因是在焊缝及母材表面存在着起始的表面裂纹。因此,必须可靠地检出并及时消除多种表面裂纹,才能确保球罐的安全运行。对于焊缝及母材表面裂纹的无损检测主要采用磁粉探伤及渗透探伤两种方法。然而,对于球罐表面裂纹的检验通常使用单方向磁化的极间式 1 Overview The analysis of a large number of domestic and international accidental failure of the tank shows that the direct cause of the failure of the tank failure is the initial surface crack on the surface of the weld and the parent material. Therefore, must be reliably detected and promptly eliminate a variety of surface cracks in order to ensure the safe operation of the spherical tank. For the non-destructive testing of weld and base metal surface cracks, two methods are mainly used: magnetic particle inspection and penetrant inspection. However, the inspection of the surface of the spherical tank usually uses one-way magnetization of the inter-polar