In horizontal position, welding bead has an inclination to become hanging bead by gravity, and this problem makes horizontal welding difficult for high-deposition rate welding. A new basic concept so called Electromagnetically Controlled Molten Pool (ECMP) welding process that used electromagnetic force was proposed to solve this problem, and it was proved the possibility by new TIG welding process (1 wire type) with ECMP in horizontal position.
In this paper, TIG welding using 2 filler wires with ECMP is proposed for higher deposition rate welding in horizontal position. 2 filler wire feeders are connected in series to a. wire heating power source, and one wire is inserted at front position, and another is inserted at rear position of the arc. So, joule heating ability and heat exchanging ability to the arc is increased comparison to 1 wire process. Farther more, area of unidirectional current in molten pool is increased by this wire arrangement. So, more wide upward electromagnetic force compared to 1 wire type is generated, and controlling ability of bead shape is increased under magnetic field.
In the test, wire melting characteristics were investigated, and it was found that stable welding was possible under high deposition rate such as 100-150g/min. Bead shape was improved remarkably, and contact angle of bottom side in weld bead was decreased under the half of magnetic flux density that was required in lwire process. V groove joint weld was done for stainless clad steel, and good penetration, smooth bead shape, sound weld joint property was obtained under high deposition rate welding condition such as 100 g/min. After these basic tests, new 2 wires type TIG welding process with ECMP was applied to huge steel structure, and practicability of this process was proved by successful result.