Drawing is a metalworking process which uses tensile forces to stretch metal. It is broken up into two types: sheet metal drawing and steel tube drawing. The specific definition for sheet metal drawing is that it involves plastic deformation over a curved axis. For wire, bar, and tube drawing the starting stock is drawn through a dye to reduce its diameter and increase its length.
The drawing off steel tubing is usually done at room temperature, thus classified as a cold working process. It may however be performed at elevated temperatures to hot work large wires, rods or hollow sections in order to reduce forces.
Bar, tube and wire drawing all work upon the same principle: the starting stock drawn through a die to reduce the diameter and increase the length. Usually the die is mounted on a draw bench. The end of the steel tube is reduced or pointed to get the end through the die. Steels, copper alloys, and aluminium alloys are common materials that are drawn. Die picture below depicts the drawing process of a steel tube.
With tube drawing, the beginning stock is a steel tube. It is used to decrease the diameter, improve surface finish and improve dimensional accuracy. A mandrel may or may not be used depending on the specific process used. The process of plug drawing can be applied if the inside diameter (id) of the steel tube needs to be controlled. A tool is then manufactured which allows the steel tube to be drawn down to the required size while ensuring that the inside diameter of the steel tube is as close as possible to the pre-set tolerance given.
Tubecon can draw or plug draw steel tubes according to customer specification. Not only does Tubecon use the drawing process for precision tubes as welded steel profiles can also be manufactured using the drawing process. For smaller quantities steel sections that are not specified as standard drawing can be a great advantage to the end consumer.
The process of drawing can take a round steel tube, called the mother tube, to a square, rectangle or profile as the end result.