Analysis for Cooling Process of Underwater Welding

—Comparison with Welding in Air—

Abstract

Underwater welding techniques have been of growing importance as a number of new projects for offshore structures are underconsideration and some of them are being put into practice. Underwater“wet type”welding is especially useful for the repair and maintenance of those structures. In the previous paper, fundamental characteristics of wet welding such as heat transfer from plate to surrounding water have been evaluated using mixed gas shield welding, and the extent of heat transfer was quantitatively estimated in terms of coefficients of heat transfer. In addition, three dimensional Finite Difference Analysis was attempted to obtain temperature distributions within the plate. In this paper, cooling process for underwater welding is compared with that for welding in air, where the effects of welding conditions such as welding speed and plate thickness are discussed. It is also shown that the cooling rates for underwater welding could be analyzed within acceptable engineering accuracy using three dimensional FDM.