Importance

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Abstract

A method for drawing seamless metal tubing particularly copper tubing under inclusion of a floating mandrel and a diameter reducing die wherein the wall thickness is reduced under cooperation of the mandrel and of the die in an action zone defined by a drawing gap between the mandrel and the die, a drawing force is applied to the drawn tube downstream from the die, a plurality of tubings are connected to each other end-to-end thereby providing a joint in each instance of connection; normally and regularly the tubing is drawn in portions not havng any point; the die is shifted in the direction of drawing while holding the mandrel as the joint approaches, or the mandrel is shifted while the die is held; the tubing is hollow drawn in and adjacent to the joint without the mandrel being in the action zone of the die for reducing the diameter of the tubing with little or no concurring reduction in the wall thickness; subsequently the mandrel or the die is returned to the action zone of the die after the joint has passed through the die so that regular drawing can be resumed.

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First Claim