Apparatus for continuous manufacture of butt-welded pipe

An apparatus for continuous manufacture of butt-welded pipes, comprising:

• a heating furnace for heating a skelp continuously passed therethrough up to a predetermined temperature;
• a heater means having at least one heater with spaced opposed induction heating coil means on opposite sides of the path along which the skelp is passed through said heater means, said induction heating coil means being a pair of induction heating coils positioned in spaced opposed relative above and below the path of the skelp, said coils having a generally rectangular shape with a width at least as wide as the skelp and having the longer side substantially aligned with the edge portions of the skelp passing through the space between said coils in a position for concentrating the current induced in the skelp for heating only the edge portions of the skelp discharged from said heating furnace up to the butt-welding temperature, and having means connected to at least one of said induction heating coil means for varying the electromagnetic coupling between said one induction heating coil means and the corresponding edge portion of the skelp for adjusting the temperature to which the corresponding edge portion is heated;
• bending means adjacent the outlet end of said heater means for bending the skelp into a generally tubular form;
• and
• butt-welding rolls adjacent the outlet end of said bending means for applying a predetermined pressure to the bent up skelp for butt-welding the edges of the skelp to each other.