The process begins in the pickle house, where tube hollows are cleaned in an acid etching tank, and lubricated
to facilitate cold drawing.
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After drying, tube hollows are pointed at one end to allow easy entry into the drawbench die.
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Tube hollows are telescoped over a mandrel mounted on a long supporting rod. The pointed end is started
through a die smaller than the hollow's outside diameter. Secured by gripper jaws, it is pulled through
the die and over the mandrel.
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To complete the process, tubes may be fully normalized, stress relief annealed or soft annealed to restore ductility.
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In the cold drawing process, electric resistance welded and ERW hot stretch reduced tube hollows are transformed
into high precision tubing. To begin the process, each hollow is pickled, lubricated, and pointed at one end. The
prepared hollow is then moved to the drawbench where it is pulled through a hardened steel or carbide die to reduce
diameter and improve outside diameter (OD) tolerance. To improve surface finish, mechanical properties and dimensional
accuracy of both outside and inside diameters (ID), hollows are also pulled over a mandrel as they progress through
the die.
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