Study on Wet Underwater Welding (Report 1)

Feasibility of Covered Electrode

Abstract

The feasibility of wet welding process in underwater with covered electrode is investigated. Welding experiments are done with HT 60 steel plate and D5003 covered electrode.
The following results are obtained:
(1) The hardness of heat-affected zone seems to be relatively low in case of two pass welding.
(2) In underwater welding, weld metal seldom has blowholes, and no cracks are observed on the weld metal in X-ray inspection.
(3) In underwater welding the oxygen absorption of weld metal is about 1.7 times of that in-air welding, the nitrogen absorption has about 0.25 times.
(4) The quantity of diffusible hydrogen collected in mercury reaches to a constant volume in about 2.4 × 10⁴ min. (408 hr).: In air welding, it is about 30 cc/100 g in case of one pass welding and about 25 cc/100 g in case of two pass welding; in underwater, it is about 70 cc/100 g in case of one pass welding and about 55 cc/ 100 g in case of two pass welding.
(5) On two pass welding, the quantity of diffusible hydrogen is about 20% less than one pass welding.