A method of laser electroslag welding

Abstract

To improve the mechanical properties of the weld metal, heat affected zone and welding productivity by increasing the speed of welding a combined method of laser electroslag welding is offered. It includes the slag and metal baths kept in the space restricted by forming copper plates and welded seam with slag heating or filler wire or melting electrode plate of the metal seam and edges welded by the heat. The heat is generated when an electric current flows between the electrode and the welded metal through the molten slag and by the heat of the laser beam with a uniform intensity distribution of laser power across the mirror surface of the weld puddle. Additional energy of a laser beam increases the temperature of the slag bath, accelerates heating of the welded edges of the electrode, increases the rate of melting or fusing of the wire electrode plate. Thus, it increases the rate of weld puddle rising and reduces the time of the weld metal and heat affected zone being under high temperatures. At the same time grain size increment is decreased. This will improve the mechanical properties of the weld metal and heat affected zone. Using laser energy in the electroslag process will allow not only to raise the temperature of the slag bath, but also to warm welded edges with a laser beam, avoiding the defect of incomplete fusion in low temperature slag bath. Moreover, laser beam can be directed to the welding wire or electrode plate to warm the filler metal which further increases the amount of metal melted per unit time.