HOT AND COLD REDUCED SEAMLESS AND WELDED PIPES

An account is given of developments by the All-Union Research and Design Institute for the Tube Industry (VNITI) in the field of cold reduction of seamless and welded pipes. The developments cover cold continuous rolling in the absence of a mandrel (reduction and sizing), reduction, reduction-elongation, reduction-sizing, and sizing mills, differential group roll drives for multistand mills, procedures for calculating the processing and power-force parameters required of these mills, and elimination of the thickened ends of pipes by reduction with tensioning. All of these developments have resulted in improvement of the quality and accuracy of the pipes.