PURPOSE: To prevent generation of a penetrator and to improve welding quality in a method for heating and press-welding the ends on the opposite side of an open pipe and producing a welded pipe by sealing the neighborhood of the heating part by a reduction flame.
CONSTITUTION: The gaseous fuel 2 released from a gas burner 1 is burned via both edges of an open pipe OP which is heated to a high temp, by an induction heating coil 4. The reducing flame part on the inside of the flame covers the pipe OP and the neighborhood of the weld point A. The open pipe OP is fed in the decreased partial pressure of the oxygen to the coil 4 to which high-frequency current is supplied from a high-frequency power source. Induction current is thus generated. The open pipe OP of which the end faces on the opposite side are heated by such induction current is pressed from both sides by squeezing rolls and is welded at the weld point A by which a welded pipe P is produced.
KABURAGI KATSUHIKO
KITAMURA TSUTOMU
| JPS5133512A | 1976-03-22 |
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