METHOD FOR MAKING TUBES USING SHAPED MANDREL WITH HELICAL RIFFLES BY DRAWING PROCESS Russian patent published in 2002 - IPC

FIELD: plastic metal working, namely,, processes for making tubes with complex-shape inner profile, mainly by drawing. SUBSTANCE: method for making tubes with helical riffles comprises steps of feeding tubular blank with mandrel into die; deforming blank in cone die on shaped mandrel with riffles fixed at side of rear end of blank with possibility of rotation and self-aligning; realizing at least one stage of preliminary drawing of initial cylindrical blank onto flat mandrel at deformation degree of 10-50% and at interference 0.1-0.4 mm before drawing on shaped mandrel with helical riffles. EFFECT: enlarged manufacturing possibilities, improved quality of tubes with helical riffles due to use of cylindrical blank with enhanced quality of its inner surface and lowered difference of wall thickness values. 1 cl