Spiral welded pipes of twenty to thirty inches dia - where bending and welding angles are controlled for optimum weld quality

摘要

Multiwire internal welding process for mfg. spiral welded pipeline pipes of small dia. (ca. 20 to 30 inches), in which both welding and bending of the sheet or strip forming the pipe are undertaken at an angle (alpha) of 5-30 degrees, esp. 5-15 degrees w.r.t. a horizontal plane along which the sheet or strip is fed. The groups of bending rollers and the inernal welding point are pref. located at an angle (alpha') of 5-30 degrees w.r.t. a vertical plane passing through the axis of the welded pipe, whereas the point of rotation of the device which pivots the pipe is pref. at angle (alpha) w.r.t. the horizontal plane.