Abstract: A pipe bending machine has a pipe feed rate setter. A bending unit has a bending roller and a drive for displacing the bending roller in the plane of bending, and a follow-up roller. The follow-up roller is arranged for engagement with the pipe after the pipe has been subjected to the action of the bending roller and is secured to one arm of a two-arm lever having a pivot axis which intersects the center line of the incoming pipe. The other arm of the lever carries a movable contact of the bending roller drive. The contact alternately engages two stationary contacts of the drive.

Abstract: A method of producing welded, thin-wall straight-seamed tubes comprises forming a strip in rolls of a tube-forming mill into a tube skelp, and then subjecting the latter to the inert-gas-shielded non-consumable electrode welding. The tube skelp is formed with a gap between edges being 1/500 to 1/30 to the tube-diameter-to-wall-thickness ratio, taken in mm. The rate of welding and the level of welding current are selected in accordance with the rate of heat release in the welding zone, which should be sufficient to close joint due to heat expansion of the tube skelp material and the formation of welding joint.