METHOD OF EXPANDING TUBES AND APPARATUS FOR PERFORMING THE SAME Russian patent published in 1996 - IPC

FIELD: tube production. SUBSTANCE: method comprises steps of securing an end of a tube in a clamping device and realizing its preliminary expanding with the aid of a mandrel, having cone and cylindrical portions; releasing the above mentioned end of the tube after it had been expanded, securing a second end of the tube and finally expanding it by drawing the mandrel along the hole length of the tube. The clamping devices for the tube are mounted on struts of a base with possibility of motion along an axis of the tube on guides. A rod, whose ends are joined with a power cylinder and a movable car, supports two mandrels for performing the expanding operation. Such structure of the apparatus provides a possibility of sizing especially thin wall tubes, having constructive thickened portions on its both ends. EFFECT: enhanced quality of especially thin wall expanded tubes. 2 cl, 6 dwg