| 摘要 |
FIELD: technological processes. ^ SUBSTANCE: invention is related to the field of metal plastic working and is related to technology of production of weld-free hot rolled pipes, in particular with application of longitudinal rolling mills. Method includes rolling of pipe billet in deformation zone of longitudinal rolling mill. Deformation zone is produced by two-roller caliber of polyhedral shape and fixed cone-shaped cylindrical mandrel. Middle of cylindrical belt of mandrel is matched with line of working rollers centers or is displaced in direction of rolling by a certain value. Caliber is arranged in the form of dodecahedral polygon. Clearance ö between cylindrical surface of mandrel and caliber facets is established in compliance with expression: ö=kS[0.5Sx<S>/100%], where ö is gap between cylindrical surface of mandrel and caliber facets, mm; k=0.985 is empiric coefficient that takes into account thermal variation of wall thickness; S is rated thickness of pipe wall, mm; <S> is tolerance band for wall thickness, %. ^ EFFECT: increase of pipe quality, yield by means of reduction of its transverse thickness variation and reduction of deficiency by availability of longitudinal rolled mark on internal surface of pipe. |
