APPARATUS AND METHOD FOR HEATING WELD PART OF STEEL PIPE MATERIAL

• Main Authors: YAMAMOTO KAZUTO, FUKUTANI KAZUHIKO, UMETSU KENJI, MIYAGAWA TAKASHI, SHIMADA RYUICHI, ISOBE TAKANORI, KITAHARA TADAYUKI, NAKAMURA YOSHIAKI
• Format: Patent
• Language: English
• Published: 28.05.2009
• Subjects: CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; ELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; PERFORMING OPERATIONS; SOLDERING OR UNSOLDERING; TRANSPORTING; WELDING; WORKING BY LASER BEAM

PROBLEM TO BE SOLVED: To precisely and efficiently control the temperature of a weld part, the shape of molten steel, and a weld frequency fluctuation irrespective of the shape of the portion to be heated of a material to be heated or the quality of the material to be heated, when continuously induction-heating and welding a moving steel pipe material as the material to be heated. SOLUTION: There are disclosed a weld part heating method for melting and press-welding a weld part of a steel pipe material, and an apparatus for the same method. The method comprises the following steps: a first photographing step of detecting the spontaneous light of the weld part by a first photographing means 3, which is arranged opposite to the weld part of the end face of the steel pipe material, to output a brightness image; a weld part temperature-distribution computing step of conducting image-processing based on a brightness image, and of computing the thickness-direction temperature distribution of the weld part by radiant-light temperature measurement; a heating control step of deciding a frequency of an alternating current based on the thickness-direction temperature distribution by using an evaluation reference of the relation between the frequency of a preset alternating current and the thickness-direction temperature distribution; and a step of feeding the alternating current of the frequency decided at the heating control step, to the steel pipe material 10 by using an alternating current power source 1 of a variable frequency. COPYRIGHT: (C)2009,JPO&INPIT