Abstrakt

A keyhole plasma arc welding technology and its physical mechanism

Yan Li

 Arc welding technology is widely used in the manufacturing of pressure vessel, oil-pipeline connection, and petroleum chemical equipment. Generally it requires good groove preparation, suited filler wire and multi-layer and multi-passes welding. Plasma Arc Welding (PAW) is one of the most advanced welding technologies with a high power density. A keyhole PAW technology can fuse the work piece through its entire thickness with a single pass and without groove preparation. It has great potential in the advanced manufacturing industry. However, it requires strict welding conditions to maintain good weld joint quality at the keyhole welding state, since it involves very complex electric, magnetic, thermal and fluid dynamics phenomena, such as electro-thermal conversion, electromagnetic effects, heat transfer, gas-liquid two-phase impact and flow, interface deformation and solid-liquid phase change.