NUMERICAL SIMULATION OF KEYHOLE FORMATION DURING PAW+TIG DOUBLE-SIDED ARC WELDING
PAW+TIG电弧双面焊接小孔形成过程的数值模拟

The mathematic model of keyhole formation in double-side arc welding is established through considering all influencing dynamic factors, such as plasma arc pressure, gravity and surface tension. With the numerical simulation technology, the dynamic process of keyhole formation is quantitatively analyzed by coupling the keyhole model with the governing equations of heat transfer. According to the numerical analysis results, the keyhole formation may be divided into three stages: from welding start to penetration, from penetration to perforation and from perforation to stable keyhole state. The minimum span in the weldpool may be regarded as the evaluation criterion of keyhole formation. The keyhole formation results from the common actions of heat and forces.