Patent ID: 9162268
Filing Date: 2015-10-20
Classification: B21C,B23K

Abstract:
1. An electric-resistance-welded pipe welding apparatus, comprising: rolls bending a metal strip traveling in one direction into a cylindrical shape so that both ends in a width direction of the metal strip face each other; an induction coil provided in an immediate proximity to the metal strip bent into the cylindrical shape so that the both ends are heated, and are welded while being pressed to and coming in contact with each other; an impeder that is disposed inside of the metal strip bent into the cylindrical shape, the impeder being disposed spanning from an end of said induction coil to the other end of the induction coil in a traveling direction of the metal strip; and a metallic shield plate that is disposed further upstream than an upstream end of the impeder and is further downstream than the rolls in the traveling direction of the metal strip, the metallic shield plate located outside said impeder and including a hole portion through which the whole metal strip bent into the cylindrical shape passes, the metallic shield plate shielding a magnetic flux generated in the induction coil, and a ferromagnetic body that is disposed between said metallic shield plate and said induction coil in a position corresponding to the upstream end of the impeder when viewed along the traveling direction of the metal strip, the position being peripheral of the metal strip bent into the cylindrical shape, and the position spanning the both ends of the metal strip, wherein: the metallic shield plate is disposed at a predetermined distance apart from the upstream end of the impeder, and the metallic shield plate is disposed to surround an outer surface of the metal strip bent into the cylindrical shape.