Analysis of Cooling Process for Underwater Welding

—Numberical Simulation Accounting for Heat Transfer Mechanism—

Abstract

Recently, the importance of underwater welding has been increasing as a number of waterfront projects are progressing. Underwater “wet type” welding is considered to be particularly useful for repairing offshore structures so built. It has essential drawbacks, however, that the weld portions are rapidly cooled due to high rates of heat dissipation into surrounding water, which decreases the strength of welded joints. In the previous paper, three dimensional Finite Difference Method has been applied to evaluate the cooling rates of underwater welding. In this report, the numerical method is improved to obtain better results to simulate the specific characteristics of cooling rates in underwater welding. The amount of heat transferred into surrounding water is evaluated by following calculation procedures proposed for corresponding heat transfer mechanism, such as free convection, nucleate boiling, etc., with surface temperatures of plates measured by thermocouples. The validity of numerical method presented here is ascertained by comparing experimental results.