METHOD OF SIZING PIPE ENDS Russian patent published in 2003 - IPC

FIELD: plastic metal working; particularly, straightening of ends of large-diameter pipes with the help of rolls. SUBSTANCE: method of sizing pipe ends contains steps of elastic deformation of pipe end being straightened and subsequent elastic deformation of this end within several cycles. Pipe is arranged with location of larger axis of cross-section oval of pipe end being straightened in horizontal plane. Elastic deformation of pipe end being straightened is carried out by means of application of forces over outside surface up to shaping this end in cross-section to oval form. Large axis of oval is located in vertical plane. Elastic deformation is performed within several cycles by means of gradual increase of curvature of pipe end being straightened. During deformation the equality is ensured between residual elastic deformation and elastic deformation in all points along the perimeter of pipe end being straightened. Elastic deformation of pipe end being straightened is carried out simultaneously on two opposite sides of cross-section oval of pipe end being straightened. EFFECT: enhanced accuracy of straightening and minimum ovality of pipes. 2 cl, 1 dwg