Abstract
The effect of water pressure on the MIG arc phenomena and bead shapes was studied in the high water pressure simulator. The results obtained are as follows.
1) Available shielding effect was obtained under high water pressure by the use of water curtain dual shielding method.
2) Bead width, penetration depth and reinforcement became narrow, deep and high respecively with increasing of water pressure under the constant welding condition, but in case of short circuiting arc, the increase of penetration was slight.
3) Critical welding current and arc voltage for stable spray transfer rised with increasing of water pressure.
4) Spatter free weld beads were obtained even in high pressure corresponding to water depth of 90 m selecting the proper welding condition.
5) Oxygen addition to argon shielding gas brought the stable spray transfer and remarkable increase of bead width and penetration especially in high water pressure.
