End-thickening during rolling on a stretch-reducing mill

A more accurate method of calculating end-thickening of stretch-reduced tubes is presented. The fundamental equations and the method for the calculation of steady-state roll speed are described; the method of calculation for changes in inter-stand tension and wall thickness in a transient state is also described. The model for the calculation contains the following variables: the steady-state roll speed, the dimensions of the entry and finished tube, the roll-groove dimensions for successive passes, the deformation resistance of the rolled material, the coefficient of friction, and the stand spacing. An example is analysed and compared with experimental results.