
A welding flux which forms a weld metal simultaneously satisfying low-oxygen, low-nitrogen, and low-hydrogen contents, gives weld beads in good form, and joins given metal pieces without entailing weld defects is obtained by formulating the flux in a composition such that a four-component system used therein is formed of CaO, MgO, Al.sub.2 O.sub.3, and SiO.sub.2 in the following proportions based on the total amount of the system taken as unity (100%), CaO: 10 to 60% MgO: Not more than 30% Al.su...










