1943: for the first time, aircraft manufacturers used atomic hydrogen welding, submerged arc welding and MIG welding to weld hollow blades of aircraft steel propellers. 1950: Three Americans, Mueller, Gibson and Anderson, obtained the first patent of MIG welding overspray. 1962: the patent right of gas-electric vertical welding was awarded to Arcos, a Belgian. 1980 or so: the printed circuit board is soldered by steam. It also produced gas cutting.