基于三维数值模拟的焊缝缺陷漏磁场分析

The Analysis for Magnetic Flux Leakage Field of the Weld Defect Based on 3D Numerical Simulation

以压力容器等焊接设备对接焊缝为对象,提出了一种基于数值模拟的焊缝缺陷漏磁场的分析方法。通过仿真分析,对比分析了不同焊接工艺(单面焊和双面焊)无缺陷、焊道上分布矩形槽缺陷及热影响区分布矩形槽缺陷时的漏磁场特征,评述了单面焊同时分布两个矩形槽缺陷对漏磁场分布的影响规律。数值模拟结果表明:双面焊这种结构对于焊道上分布矩形槽时的漏磁场的影响更大;两个缺陷同时存在时,缺陷之间的距离是影响缺陷漏磁场分布的主要因素。

This paper presents an approach based on numerical simulation for the magnetic flux leakage(MFL)field for the butt weld of the welding equipment such as the pressure vessel in order to study the weld defect.Comparative analysis of the leakage field characteristics was made for different welding processes(single-sided weld and double-sided weld)of having no defects,defects in the weld and defects in heat-affected zone with finite element method(FEM)numerical simulation.Also,the laws of distribution of the MFL field are meanwhile studied when two rectangular defects are pre-made in the single-sided weld.Simulation results show that the double-sided weld has greater impact on the defect in the weld;also under the situation of co-existence of two defects the distance between the defects is the main factor to affect the MFL field distribution.