Patent ID: 6012313
Filing Date: 2000-01-11
Classification: B21B

Abstract:
Process for creation and regulation of an external force to apply to a feed assembly of preformed forgings in cold rolling mills with rollers and mandrel, processing and smoothing racks, of the ""pilgrim process"" type for producing seamless tubes, in whichsaid external force is calculated by a computer in accordance with geometric parameters of contours of the rollers and mandrel, with a value of a coefficient of friction between the preformed forging, rollers and mandrel and in accordance with a reaction generated in roller supports for the rollers, in which the external force applied to the feed assembly is calculated by the computer based on the following formulae: ##EQU2## L res=A an eff where:EF lim: nominal limit external forceEF eff: effective external forceL res: residual longitudinal rolling forceNs: normal force on the portion being processed.mu.: coefficient of frictionlpma: Length of arc of contact of part of mandrelr: radius of mandrelR: radius of preformed forgingS sb: section of preformed forgingS ma: section of mandrel.psi.: angle of inclination of portion being processed.psi. ma: angle of inclination of mandrel contour.beta.=z/lpz: distance between points of contour of portion processed and center of rollers.lp: length of arc of contactA an rit: extra outgoing friction braking power to avoid detachment during return strokeA an eff: extra outgoing force of friction to raise EF from nominal to effective value.