Kink-free uncoiled annealed pipe - is obtd. by subjecting pipe to compression-tension deformation in drawing die to reduce outside dia.

摘要

The annealed pipe up to 40 mm dia is stored in coiled condition, and when it is uncoiled it tends to develop kinks at spaced intervals. This is avoided by using a drawing die through which the annealed pipe is drawn while force is applied at the end of the pipe on the outlet side of the die. The outside dia of the pipe is reduced by is not 4%. The die is positioned at a point where the circular shape of the pipe changes over to a straight line. As an alternative two sets of grooved roller can be used forming an opening which is smaller than the outside diameter of the pipe. The two sets are arranged in series and at ninety degrees rotation axes to each other.