To uniformly heat a steel pipe by using a high-frequency heating coil, in a hot working device of the steel pipe.
The steel pipe W fed out of a bending pivot member 12 of a steel pipe feed-out device 11 is induction-heated by passing the high-frequency heating coil 13, and is subjected to bending processing by applying thereto the bending moment by a bending device 15. Since a pre-heating means composed of an electric heater 16 for pre-heating the steel pipe W is arranged in the bending pivot member 12 at the upstream side of the feed-out direction of the steel pipe W rather than the high-frequency heating coil 13, it becomes possible to pre-heat the steel pipe W in advance at a prescribed temperature by using the electric heater 16 before heating the steel pipe by the high-frequency heating coil 13, and the processing accuracy of bending processing can be enhanced by suppressing a temperature difference among each part of the steel pipe W at a time point when performing the bending processing after the finish of heating by the high-frequency heating coil 13.
SAYAMA MITSURU
Kazuaki Niki
Nude Shima Shinji
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