Kemppi HiArc S 140 Operating Manual

Contents

9© Kemppi Oy / 1418EN93. useNOTE! It is forbidden to weld in places where there is a danger of fire orexplosion!3.1 Welding processes3.1.1 manual metal arc welding (mma)In manual metal arc welding (MMA) the welding filler material is meltedfrom the electrode to the weld pool. The rate of the welding current isselected based on the electrode size used and the welding position. Arcforms between electrode tip and welding piece. The melting electrodecoating forms gas and slag, which protects the weld pool. Slag solidifiedover the weld is removed after welding e.g. with a chipping hammer (use ofeye protection is strongly advised).3.1.2 tig weldingIn DC TIG welding, the arc between the tungsten electrode and the weldingpiece melts the welding piece, thus forming a weld pool. Arc and electrodeare shielded by an inert shielding gas (argon). If necessary, filler is used. Fillerwire is fed into the weld pool from the outside of the arc. The filler wire andthe welding current level are decided according to the base material typeand thickness, joint form and welding position.