UA92241C2 - Method of continuous longitudinal rolling of pipes in multiple-stand mill on mandrel - Google Patents

Abstract

The invention relates to metal forming and can be used on the multiple-stand mills at continuous rolling on the mandrel of the seamless pipes from ferrous and nonferrous metals both in cold and hot state. Deformation of a billet is carried out on a mandrel in a set of consecutive passes formed by driving rollers, which angular velocity () in each-th mill stand is determined by the mathematical relationship as a function of velocity () of a pipe at the outlet of mill, traction of the billet () and tension coefficient () in each of the next mill stand, total number () of the stands of multiple-stand mill, and the number of rolls () forming each of the passes with further application of the law of change of the roll diameter () on the perimeter of each pass and the angle of displacement of the center () of each pass. The invention allows to create conditions for predominant plastic flow of metal in the rolling direction, that ensures elimination of overflow of passes by metal, and prevents metal flowing into the gaps between the rollers and prevents formation of scores and coils on the pipes.