Welding and cutting under water

The chapter presents the definitions of underwater welding and cutting, features of underwater welding, classification of underwater welding methods, main problems of different underwater welding methods, the influence of hydrostatic pressure on stable arc burning in an aqueous medium, and features of metallurgical processes at different underwater welding methods. Recommended welding consumables and main types of defects are described. Features of the thermal cycle of underwater wet welding and its effect on the structure of the weld metal and HAZ are shown. Described an influence of main technological parameters on welding defects formation and welded joints properties at MMA, GMAW, FCAW underwater wet welding. Applied equipment, macro- and microstructure of welded joints and HAZ, advantages and disadvantages of the method, product examples, and areas of application are shown.