B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
B23K20/14—Preventing or minimising gas access, or using protective gases or vacuum during welding
Procede pour la fabrication d'une surface de chauffe d'une chaudiere exempte de condensation d'eau, composee d'une enveloppe interieure et d'une enveloppe exterieure, et surface de chauffe fabriquee par ce procede