In situ strain evaluation during TIG welding determined by backside digital image correlation

The in situ strain field measurement during a tungsten inert gas welding of 1 mm-thick stainless steel butt joint was evaluated by three-dimensional digital image correlation (DIC). The experiments were designed to measure the strain evolution in the vicinity of the weld pool from the backside of the steel plate to prevent intense welding arc from deteriorating digital image quality and also provided a way to measure transient strain field during welding, especially for welding of thin materials. The in situ strain field under different welding parameters in the vicinity of weld was analyzed. The strain evolution around 5 mm away from the weld center line could be measured.