ROLL GROOVED PASS SYSTEM OF COGGING MILL Russian patent published in 1998 - IPC

FIELD: rolled stock production, namely roll grooved pass system of cogging mill, mainly for making blanks, large steel bars, possibly in reversing cogging mills. SUBSTANCE: initial square or rectangular cross section blank is heated in heating furnace of cogging mill and it is rolled in successively arranged along roll barrels flat and square box passes at tilting rolled pieces by 90 degrees between passes. When rolled plate is fed out of square box pass with joining of its flat bottom surfaces and lateral faces by radiuses R1, it is also tilted by 90 deg and rolled in pass formed by U-shaped cross section grooves. Grooved pass is bent in central portion along its symmetry axis Y-Y normal relative to roll axes. Bending of grooved pass is formed by symmetrical slopes of its bottom surfaces relative to plane X1-X1 parallel to roll axes and equal to 0.7-0.8 of outlet slope of square box pass. U-shaped grooved pass has outlet slope 105-115% and radiuses of joining its bottom surfaces with lateral faces equal to 1.15-1.5 of radiuses R1 of respective surfaces and faces of square box pass. Rolled in that pass rolled piece is tilted by 90 deg and rolled in diagonal box pass. Square cross section strip is used as semifinished product for further rolling in small bar rolling mills or in the same cogging mill in successive oval and round cross section grooved pass for receiving round blank. EFFECT: stabilization of rolled piece position in diagonal box pass, elimination of twisting rolled piece fed out of U-shaped grooved pass to diagonal square box pass, simplified manipulation of rolled piece such as tilting, cross motion and so on. 1 tbl, 3 dwg