METHOD OF ROUND STRAIGHT-LINE-SEAM PIPES PRODUCTION Russian patent published in 2009 - IPC B21C37/06 

FIELD: metallurgy.

SUBSTANCE: in moulding midsection of the strip is bent along the lines, reverse pipe curvature, and side sections of strip are formed in the form of two arcs of equal curvature, which are kept at consequent passages in undeformed conditions. In following passages received profiled strip is bent till edges closing. Then edges are welded. Bending of initial strip midsection is implemented at curvature, defined from ratio: ρ=(k×d-b)^-1, where ρ - curvature of strip midsection bend, m^-1; d - pipe diameter, m; k - constant of proportionality, equal to 7.1-7.7; b - coefficient, equal to 0.026; with arc length at each side section of strip is 0.1-0.2 of pipe perimeter of circle.

EFFECT: pipes improving and yield.

2 dwg, 1 tbl, 1 ex