New Seamless Pipe Rolling Technology for Higher Dimensional Accuracy

Abstract

It is a recent tendency that higher accuracy in dimensions of seamless pipe has been more frequently requested as the application becomes more critical.
Technology which has enabled to obtain higher dimensional accuracy in a mass production line of seamless pipe is described here on each process from bloom reheating to sizing. The technologies involve the individual method for prevention of eccentricity at Mannesmann Piercer and Press Roll Piercer, reduction of eccentricity at Elongator, improvement of wall thickness accuracy at Plug Mill, Mandrel Mill and Semi-floating Mandrel Mill, improvement of outer-diameter accuracy at Sizer and prevention of hexagon at Stretch Reducer. Some of actual dimensional accuracy data achieved with the PRP-Plug Mill which has been installed recently in Japan are also shown.