| 摘要 |
FIELD: rolled tube production, namely piercing sleeves of ingots having shrink holes and of drilled blanks of steel kinds with trend to occurring in back ends of sleeves so called "triangles", possibly manufacture of tubes in tube rolling plants with pilger mills. ^ SUBSTANCE: method comprises steps of deforming ingots and blanks on mandrel by means of working rolls, idle rollers and liners; moving axes of rollers in horizontal plane towards sleeve rotation beginning from time moment of mandrel approaching to shrink hole and load growing of mill drive. Deformation of ingots and blanks is realized in pass formed by working rolls, idle rollers or liners. Axes of rollers or liners are arranged stationary at shifting them in horizontal plane relative to piercing axis to side of sleeve rotation while in vertical plane shifting to piercing axis for rollers and from piercing axis for liners. Axes of idle rollers are shifted in horizontal plane relative to piercing axis to side of sleeve rotation by value L and in vertical plane to piercing axis by value Li. L = KDr + Ds/Ss; Li = K1 Dr +Ds/Ss, where Dr - diameter of idle roller on constricted portion, mm; Ds - outer diameter of sleeve, mm; Ss - sleeve wall thickness, mm; K = (0.2 - 0.3) - factor taking into account geometry size of sleeves for determining shifting value of idle roller axes in horizontal plane; K1 = (0.02 - 0.03) - factor taking into account geometry size of sleeves for determining value of shifting axes of idle rollers in vertical plane. Shifting value of liners axes in horizontal plane relative to piercing axis L2 = Ds/Ss and in vertical plane their shifting from piercing axis L3 = K2 x Ds/Ss, where K2 = (0.5 -1.0) - factor taking into account geometry size of sleeves for determining shifting value of liner axes in vertical plane. Large values of factors K, K1, K2 are set for sleeves with high relation Ds/Ss. Invention provides lowered metal consumption at rolling tubes in tube rolling plants with pilger mill from ingots with diameters 550 mm and more and from drilled blanks with diameter 600 mm and more. ^ EFFECT: improved quality of sleeves due to lowered number or complete elimination of "triangles" in end portions of thin-wall sleeves. ^ 3 cl |
