Abstract
With a given plate thickness from 6.0mm to 25.4mm and under a given welding conditions, the depth of penetration of weld made by DCSP TIG arc is approximately calculable from the equation of proportional distribution. Underbead reinforcement size is easily controllable by using the DCSP TIG arc. In the case of butt welding of the bead-on-plate and V groove provided with the backing strip, porosities are concentrated in a range less than approximately 3mm in depth from the top of the reinforcement. Porosities hardly exist in a part of weld refused by the DCSP TIG arc. The number of porosities can be decreased by increasing the depth of penetration.
