Electromagnetic Inspection Method of Outer Side Defect on Small and Thick Steel Tube Using Both AC and DC Magnetic Fields
Electromagnetic Inspection Method of Outer Side Defect on Small and Thick Steel Tube Using Both AC and DC Magnetic Fields
复制标题
DOI：
10.1109/tmag.2009.2024894
复制
发表时间：
2009-09
影响因子：
2.1
通讯作者：
Y. Gotoh;K. Sakurai;N. Takahashi
中科院分区：
文献类型：
--
作者：
Y. Gotoh;K. Sakurai;N. Takahashi
由于各种电厂和石油化工厂的热交换器中使用了小直径的厚钢管，因此这些钢管的检测非常重要。在这些小钢管上经常观察到外侧缺陷。此外，由于热交换器中的这些钢管是作为捆储存的，因此需要从管的内部检查这些钢管的外侧缺陷。本文提出了一种利用直流（dc）磁场和交流（ac）磁场的电磁检测方法。利用三维有限元法研究了焊剂在钢中的行为，并考虑了磁滞回线（小回线）和涡流。结果表明，外侧缺陷的检测是可能的，通过微分磁导率的小回线的位置上的磁滞回线的缺陷的存在的影响。
As thick steel tubes of small diameter are used in heat exchangers in various electric power plants and petrochemical plants, the inspection of these steel tubes is very important. The outer side defects are often observed on these small steel tubes. Moreover, since these steel tubes in heat exchangers are stored as a bundle, it is necessary to inspect the outer side defects of these steel tubes from the inside of the tube. In this paper, the electromagnetic inspection method using a direct current (dc) magnetic field and an alternating current (ac) magnetic field is proposed. The behavior of flux in steel is examined using 3-D finite-element method (FEM) taking account of hysteresis (minor loop) and eddy current. It is shown that the detection of outer side defect is possible by the differential permeability of minor loop of which the position on the hysteresis loop is affected by the existence of the defect.