DEVELOPMENT OF AUTOMATIC UNDERWATER WELDING SYSTEM

This paper describes the development of an automatic underwater welding system based on a unique localized dry environment by a fluid curtain. In this process, a stabilzed gaseous zone can be created only around the welding spot just underneath the welding torch by an inclined water jet stream from the outer circumference of the double nozzle. With only the welding machine submerged, the system is operated by remote control in the ocean in connection with materials supply and supervision of work, thus considerably reducing its reliance on diving and underwater operations. Welding results have proved excellent, being not much different from those undertaken in an ordinary environment on land. The fundamental data was published last year which was obtained by the experiments in a cistern. The authors submerged large steel blocks in the sea and conducted comprehensive simulated tests of the underwater welding system from the setting of the blocks and a trial manufactured welding machine to underwater welding by that welding machine are as reported. The underwater inspection technique which is one of surrounding techniques of the underwater welding and the results of fundamental tests concerning the radiographic and ultrasonic inspections are explained.