UA82971C2 - Method of continuous plugless longitudinal pipe rolling in multi-stand mill - Google Patents

Abstract

The invention relates to the methods for producing the seamless and welded pipes on reducing and sizing mills. A method of continuous plugless longitudinal pipe rolling in multi-stand mill includes deformation of billet in several consecutive roll openings formed by driven rollers. The angular velocity of roller in each-th stand of mill is determined in accordance with the relationship:,where- angular rate of rotation of rollers in the stand with current number, radian per second;- rate of billet at mill inlet, m/s;- thickness of the wall of billet at mill inlet, m;- diameter of billet at mill inlet, m;- thickness of the wall of pipe at outlet from previous-th stand, m;- average diameter of roll opening in the previous stand with current number, m;- thickness of the wall of pipe at outlet from the stand with current number, m;- average diameter of roll opening in the stand with current number, m;- ideal diameter of rollers in the stand with current number;- instantaneous value of radius of roll opening in-th stand of mill set in the form of the law of variation of the radius of roll opening along its perimeter, m;- instantaneous value of the radius of roll opening in-th stand of mill at, m;- angle between radiusand line, which penetrates the center of roll opening and its apex, radian;- angle of neutral intersection in the stand with current number, radian;= 1, 2, ... ,- 1,- ordinal number of stand assuming as= 1 first stand in the direction of rolling;N - total quantity of stands in multi-stand mill of continuous plugless pipe rolling;=– 1.The invention makes it possible to decrease the divergence between real and assigned nominal thickness of the wall of finished pipes by 33%.