Redrawing: While a large proportion of tubes receive only one cold draw pass, many require a number of passes for the reasons mentioned in the previous section. Because cold drawing hardens and reduces the ductility of tubes, it is necessary to anneal them after each cold drawing operation. Before further cold drawing, the annealed tubes must be cleaned as mentioned earlier. All tubes receive a final anneal or heat treatment after the last cold draw pass.

Straightening: The removal of sweep and camber is performed by a gag press. The gag press is a straightening device that can straighten tubes to very tight tolerances. All tubes are carefully measured for outside diameter, size, and wall thickness. A protective coat of oil, or rust preventative can be applied before shipment.

Sink Drawing: The process consists of pulling the tube through a die, the hole of which is smaller than the outside diameter of the tube being drawn. The resistance of the metal to passage through this restricted space exceeds the yield strength of the metal at this section, resulting in a plastic flow. The metal passing through the die is subjected to stress almost up to its breaking strength and is thus given a test of its physical fitness to withstand high stress in its ultimate service. Any flaw or defect of consequence is brought to light under this severe treatment.

Chain speed is automatically controlled so that the tube is started through the die at a slow speed, and, as soon as it is fairly started, the speed increases to predetermined drawing rate. Dies are made with a conical outer surface which fits in a holder mounted at a die head. Dies are made with either tungsten-carbide inserts or hardened tool steel.

The operation starts when shot blasted tubes are delivered to the draw bench. A draw bench is a heavy steel frame or bench on which is located a die head for holding a die. Louisiana Steel utilizes four draw benches rated from 50,000 to 1,000,000 pounds of draw capacity. These benches produce a finished size range of .750 inch to 16 inch outside diameter on rounds, and .750 inch to 12 inch on square and rectangular products.

At one end of the bench is located a holder to anchor the die. At the other end a shaft is mounted carrying a sprocket wheel over which passes a heavy, endless, square linked chain. This chain lies in a trough on top of the bench, which extends from the sprocket wheel to the die head, where the chain passes around an idler and returns underneath the bench to the sprocket wheel. The sprocket wheel is driven by a variable motor through suitable reduction gearing. A carriage called a "plyer" runs on tracks on top of the bench and over the chain that lies in the trough between the tracks. The plyer is equipped on one end with the jaws to grip the tube and on the other end with a hook to engage a link of the draw chain. The plyer is connected by cable to a motor actuated drum by which means it is returned to the die head after drawing the tube. The jaws grip the end of the tube, which projects through the die about 6 inches. The material is then pulled through the die thus reducing the OD. Such a reduction results in a thickening of the tube wall, which is uniform and predictable; however, the inside diameter cannot be held to the close tolerances produced with the use of a mandrel support. All controls for the draw benches are grouped at the operator's position near the head so he does not have to move away from the position when operating the bench.