Shielding conditions of local cavity for underwater arc spot welding
- Shikoku National Industrial Research Inst., Takamatsu, Kagawa (Japan)
- Industrial Technology Institute, Yamaguchi City, Yamaguchi (Japan)
Arc spot welding to join lapped plates is an effective maintenance operation for emergent recovering technique of defects under water. The welding operation is easy and effective except for an excessive amount of weld metal for deep penetration. A special nozzle for CO{sub 2} arc spot welding was designed to maintain this defect. A large amount of swirl shielding gas flow is adopted to discharge the excessive weld metal and to reduce digging action of weld pool. An additional high speed air jet is supplied to reinforce these effects. Almost flat weld bead is obtained by using of this nozzle. The effect of swirl shielding flow and additional air jet on the pressure is studied. When an excessive axial gas flow is used, a pressure at the weld pool becomes high enough to press down the weld surface below original surface level of base plate, and some molten metal is splashed out. Then, it is difficult to get a sound weld geometry. A swirl gas flow is tried to reduce the static pressure on the weld pool. The pressure on the weld pool by the swirl flow becomes much lower compared to the case by axial flow. When the swirl flow is used, a flat bead can be obtained. But some molten metal which is blown out by the swirl gas is resolidified at the edge of the nozzle. The additional high speed air jet is required to blow out the splashed metal from the nozzle completely. It has a suction effect itself. The pressure on the weld pool is also decreased. But the interaction between the swirl flow and the additional jet shows a complicated manner. This paper discusses the interaction between main shielding gas flow and the additional air jet to guarantee the good shielding condition for underwater use.
- OSTI ID:
- 403601
- Report Number(s):
- CONF-9606279-; ISBN 0-7918-1492-0; TRN: IM9651%%636
- Resource Relation:
- Conference: 14. international conference on offshore mechanics arctic engineering (OMAE), Florence (Italy), 16-20 Jun 1996; Other Information: PBD: 1996; Related Information: Is Part Of OMAE 1996 -- Proceedings of the 15. international conference on offshore mechanics and arctic engineering. Volume 3: Materials engineering; Salama, M.M. [ed.] [Conoco Inc., Ponca City, OK (United States)]; Toyoda, Masao [ed.] [Osaka Univ. (Japan)]; Liu, S. [ed.] [Colorado School of Mines, Golden, CO (United States)]; Santos, J.F. dos [ed.] [GKSS, Geesthacht (Germany)]; Stacey, A. [ed.] [Health and Safety Executive, London (United Kingdom)]; Tubby, P.; Pisarski, H. [eds.] [TWI, Cambridge (United Kingdom)]; PB: 579 p.
- Country of Publication:
- United States
- Language:
- English
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