Automation of arc welding process is very important to improve weld quality and cost performance. However, arc welding process has not fully understood, because of less knowledge on arc behavior. Behavior of heat transfer during arc welding is much influenced by metal composite, arc voltage, arc current and shielding gas. The welding process was captured by high-speed video systems in high pressure chamber. Three-dimensional behavior of heat transfer and motion of liquid metal surface has been analyzed. Full color image and near infrared monochrome image have different information on arc and metal condition. Then, deeper consideration on defect formation during welding process becomes possible.
