Nippon Steel Corporation

Teruo Tanimoto

Hajime Nakasugi

Tsutomu Sakimoto

Tsurugi Kimura

In the method of heat-treatment of welded pipe having a reinforcement weld bead therealong by heating the pipe by using an induction heating device and then by cooling it, the bead which has just been heated by the induction heating device, is further heated by a bead heater to a temperature such that the temperature difference between the metal of the pipe and the bead is smaller than a temperature difference which will produce a bad influence on the quality of the pipe. In the apparatus for heat-treatment of welded pipe having a reinforcement weld bear therealong by heating and then by cooling the pipe respectively by a heating device and a cooling device arranged in the direction of travel of the pipe, there is provided between the heating device and the cooling device a temperature-difference detector for detecting the temperature difference between the metal of the pipe and the bead, and also a bead heater for heating the bead so as to make the temperature difference between the metal of the pipe and the bead smaller than the aforementioned temperature difference.

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Kisarazu, Japan

Teruo Tanimoto