抑制高速GMAW驼峰焊道的外加磁场数值分析

当熔化极气体保护焊的焊接速度高于一定临界值时，会出现驼峰焊道成形缺陷.为防止驼峰焊道的出现，通过外加磁场与熔池中的焊接电流相互作用，产生指向熔池前方的电磁力，抑制熔池中后向液体流的动量从而抑制驼峰的产生.通过建立焊前工件上外加磁场的三维模型，计算了工件上的外加电磁场分布.提出热-磁耦合分析方法，实现焊接过程中熔池内外加电磁场的数值计算.结果表明，高速焊过程中，外加磁场主要以横向磁场分布在熔池区；焊丝与磁极间的距离会显著改变熔池内外加横向磁场的分布.

Numerical simulation of external magnetic field for suppressing humping bead in high speed GMAW process

When the welding speed is beyond a critical value, humping bead will occur in conventional gas metal arc welding (GMAW) process. To prevent the occurrence of humping bead, an external magnetic field is exerted on the weld pool to produce a forward electromagnetic force and to impede the backward flow metal jet. A three-dimensional numerical model is established to calculate the distribution of external magnetic field on work-piece before welding. And a thermal-magnetic coupled analysis is presented to calculate the distribution of magnetic field in weld pool during the welding process. Simulation results show that the applied magnetic field is in transverse direction in the weld pool regions. The distance between the wire and the magnet pole plays an important role in affecting the distribution of the external magnetic field.