 During the 1920s , major advances were made in welding technology , including the introduction of automatic welding in 1920 , in which electrode wire was fed continuously . Shielding gas became a subject receiving much attention , as scientists attempted to protect welds from the effects of oxygen and nitrogen in the atmosphere . <unk> and brittleness were the primary problems , and the solutions that developed included the use of hydrogen , argon , and helium as welding atmospheres . During the following decade , further advances allowed for the welding of reactive metals like aluminum and magnesium . This in conjunction with developments in automatic welding , alternating current , and fluxes fed a major expansion of arc welding during the 1930s and then during World War II . In 1930 , the first all @-@ welded merchant vessel , M / S Carolinian , was launched . 
