Arc Welding in Hyperbaric Atmosphere

Abstract

Argon gas is useful for conventional gas shielded arc welding in air, but it is harmful to diver/welder's health in pressurized atmosphere such as underwater hyperbaric welding. Although helium gas is more expensive than argon gas, it is the safest among other inert gases in pressurized atmosphere. Accordingly, this report describes the effects of ambient pressure up to 10 kg/cm²abs., shielding gases and welding parameteres on welding arc behaviors in pressurized atmosphere, that is, simulated underwater hyperbaric welding.
The results obtained are summerized as follows;
1) Arc voltage during TIG, MIG and SMA welding becomes higher with an increase in ambient pressure.
2) Arc voltage during TIG and MIG welding with helium gas shielding is higher than that with argon gas shielding.
3) Arc voltage during TIG and MIG welding is elevated by an increase in welding current.
4) Penetration depth of welded bead becomes deeper as ambient pressure increases.
5) Number of short circuiting transfer per second during MIG and SMA welding increase with an increasing in ambient pressure when weldingparameters are the same.
* Kawasaki Heavy Industries, Ltd.