Deformation zones along the down trajectories of skelps forming using the forming mill TESA10-50 (Pipe Electrical Welding Unit) were considered. For pipes with 50×1.5 mm diameter, strained conditions for forming zones were identified for different options of down trajectories length with the as-formed skelp initial position upward gradient within the range of H = 0÷50 mm. It was determined that increase in the down trajectory length contributed to the decrease in longitudinal strain values, however, it could not provide for forming within the allowable values along the entire forming zone of the mill. Reduction in the skelp curvature by 8÷13 % resulted in the longitudinal strains decrease at the skelp edge along the entire forming zone length.