Abstract: Dieless drawing of tapered square pipe was carried out. The influences of process parameters on the variation of pipe profile， section shape and conical degree were studied. The influence factors and law on the section rounding of square pipe were analyzed and the methods of alleviating rounding factor were given out. In the experiments， square section steel pipes were mainly used， and tapered pipes with large angles were obtained. The drawing precise can be conducted within an error of 1.0% in taper angle. The tapered pipe profile drawn by dieless drawing is in good agrees with the calculated ones. The expansion rate of section shape decreases with the increase of deformation width. The thicker the wall， the larger the expansion rate. When the wall thickness and width are all relatively large， the expansion is relatively little.

Key words: dieless drawing, tapered square pipe, cone angle precision, section shape expansion rate, deformation width