| 摘要 |
<P>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. <P>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. <P>COPYRIGHT: (C)2009,JPO&INPIT |
