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Work on underwater arc welding is still under development stages. U. S.A., U. S.S. R., U. K. and Japan are still working upon the ways to improve the quality of “wet” welds in water. Under­water arc wet welding is the cheapest and most convenient of all the welding processes avail­able to-date. Future work may be […]

The following summary projects the important aspects of underwater welding from the point of view of a welding engineer: 1 . Underwater welding is carried out where the cost or impracticability of bringing the structures to be welded to the surface prohibit the use of conventional air welding. 2. Shielded metal arc wet-welding is most […]

M. Hamasaki (Government Industrial Research Institute, Japan) and M. Watanabe (The Weld­ing Institute of Japan and Osaka University) have described the development in UWW in Japan. Among the methods being used are gravity welding and firecracker welding (also known in Europe as the Elin-Hafergut Method). In the latter process either one or two electrodes are […]

Non-equilibrium microstructures were obtained in underwater welding due to the fast cooling rates which resulted in the formation of martensite and bainite in the heat affective zone (HAZ) adjacent to the fusion line. The HAZ of under water-welds was not wide as that of similar air welds. The width of coarse grains zone of air […]

Madatov in 1969 studied the weld shapes obtained in underwater welds using 5 mm EPS 52 (iron powder) electrodes and represented these in terms of weld penetration shape factor or simply “shape-factor” defined as the ratio between the weld width and depth of penetration. He reported that as welding current increased, weld reinforcement remained constant […]

Flux covering for underwater welding electrodes should have some special characteristics in addition to the usual characteristics required in air welding. Because of arc constriction effect, the current density of underwater arc column is more and therefore deeper penetration is obtained in underwater welding. The arc should therefore have soft behaviour. Purely cellulosic electrodes are […]

Underwater welding is generally carried out where the cost or impracticability of bringing the structure to be welded to the surface prohibits the conventional air welding to be carried out. It finds its application in the repair and construction of structures inside water. In countries like USA, USSR, UK and Japan dry and wet processes […]

Deposition of stringer beads (see Fig. 15.7) has, generally, been recommended in the literature. Necessary strength can be achieved by superimposing additional beads. The advan­tages of stringer-bead technique include: 1. Easy control over travel speed. 2. Uniform bead surface. 3. Good arc stability. 4. Reduced risk of slag inclusions. 5. Reduced chances of undercutting. 6. […]

There are four basic types of UWW techniques in use today. 15.3.1 Dry Hyperbaric Chamber Process (See Fig. 15.3) (i) Weldment and welder completely enclosed. (ii) Weld properties similar to air welds. (tit) Equipment-bulky, costly, and complex. (iv) Fit-up time is more. Operational Views »Habitat Welding’1 (a) Ship repairs Fig. 15.3 Use of Hyperbaric chambers […]