| 摘要 |
The invention relates to the methods of working metals by pressure and can be used on multi-stand reducing (sizing) for continuous plugless rolling of seamless and welded pipes from ferrous and nonferrous metals. Sequential deformation of billet in each i-th stand of the mill by rolls with gages, at which in each of stands of medium group the deformation of the billet is performed with partial reduction along diameter, being larger in value than partial reduction of billet along diameter in any of the stands of main and calibrating groups, moreover, in each paired stand of medium group is installed the value of partial reduction less than in the previous paired stand. Reduction along the diameter in each paired stand of medium group is installed within the limits of 1.01-1.02 of partial reduction along the diameter in the previous unpaired stand of medium group, partial reduction along the diameter in each unpaired stand of medium group is installed within limits of 0.96-0.98 of partial reduction along the diameter in the previous paired stand of medium group, and the intensity of change of partial reduction along diameter in the medium group of stands is installed within the limits of Ii=0.045-0.065%. At use of the claimed method allows to reduce relative transverse different-walled of pipes and, accordingly, the decrease of their rejection.
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