METHOD FOR PRODUCTION OF ELECTRIC-WELDED PIPES AND MACHINE THEREFOR Russian patent published in 1994 - IPC

FIELD: metal pressure shaping. SUBSTANCE: method for production of electric-welded pipes includes joining of individual rolls into continuous strip; flexing of the latter with tensioning in driverless multiple roll bending and tensioning device; drawing the strip through the latter by pulling device; forming of the strip into skelp; welding of skelp edges; sizing of skelp into a finished pipe. The new feature is that maximal strip curvature value by its bending around the bending rolls is determined as a function of the processed strip thickness, minimal strip thickness from the machine assortment, minimum and maximum allowable bending deformation values for the outer layer, and is calculated from a mathematical dependence. Machine for production of steel pipes includes successively installed device for joining the rolls into continuous strip, bending and tensioning device, pulling and forming device, welding unit, and sizing assembly. The bending and tensioning device is provided with K sets of bending rolls of different diameters; the roll diameters for the L-th set are determined from a mathematical dependence. Furthermore, the bending rolls in the bending and tensioning device are enveloped by the strip in pairs, with changing of the strip curvature sign between the said pairs only. EFFECT: increased pipe welding machine output; increased quality of the pipes produced; decreased metal consumption by pipe production. 3 cl, 3 dwg, 1 tbl