HIGH EFFICIENCY WELDING METHOD EXCELLENT IN WELDED JOINT PERFORMANCE

• Main Authors: IESAWA TORU, ONOE HISAHIRO, KANETANI KEN, OKOCHI TOSHIHIRO
• Format: Patent
• Language: English
• Published: 21.05.1993
• Subjects: CHEMISTRY; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MACHINE TOOLS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; SOLDERING OR UNSOLDERING; TRANSPORTING; WELDING; WORKING BY LASER BEAM

PURPOSE:To prevent the deterioration of the welded joint performance even in high heat input welding of extremely thick steels having high tensile strength by injecting cooling water to the rear of weld zone base metals, generating a violent tuberlent flow of the cooling water in the vicinity of the base metal surface to increase a coefficient of heat transfer and reducing the time when a heat-affected zone of the base metals is exposed to the high temperature. CONSTITUTION:Straps 2 are fitted to the sides of the steel base metals 1-a and 1-b and electroslag welding is performed on the inside of a recessed groove 3 extending vertically. At this time, injection pipes 4 of the cooling water 7 are arranged toward the rear of a weld zone of the base metal 1-a and the quantity of water 10-2000l/m /min (hydraulic pressure 0.5-10kg/cm ) of the cooling water is injected from the two injection pipes at the same time. The changeover is carried out from the lower injection pipe to the upper one in order following the ascent of the welding position. Consequently, austenite crystal grains of the welding heat-affected zone are not coarsened, generation of upper bainite structure is prevented and joint toughness is maintained.