DEVICE FOR PRODUCING ELECTRIC WELDED PIPE

摘要

PURPOSE:To produce a steel pipe with simple constitution with higher welding efficiency by providing saddle-shaped ferrite cores obtd. by integral molding of the outside in the butt part of a steel hoop which is successively formed to a cylindrical shape. CONSTITUTION:A steel hoop 3 which is formed to a cylindrical shape is heated at the butt part by the high frequency current induced by a work coil 1. Saddle- shaped ferrite cores 2a, 2b conforming to the shape in the butt part of the hoop 3 are attached to the butt part apart at a same space from the outside surface of the strip 3. As a result, the high frequency current concentrates at the butt part by which said part is locally heated at high efficiency. The butt part of the strip 3 is heated to the welding temp. and is welded. The butt part of the hoop 3 is then pressed and stuck by squeezing rollers 4. A welded steel strip 8 is thus produced and delivered.