Cold drawing is a process of reducing the cross section of wire by pulling it through a die or series of dies. This reduces the diameter of the finished wire, improves surface finish, increases mechanical properties and dimensional tolerances. It is also used to reduce the thickness of solid bar materials such as round, hexagonal, square or rectangular rods.
The starting point for the drawing process is hot rolled bar or coils with a size appropriate for the desired final product. The pointed ends of the material are reduced in size to make them smaller than the opening of the die, after which the material is drawn through the dies, reducing its section and shaping its profile. The resulting finished product, which is known as Cold Drawn or Cold Finished, has a bright finish, increased mechanical properties, improved machinability and precise and uniform dimensional tolerances.
TY Metal has invested in high-end machinery to meet the increasing demands for quality drawn wires. Our state-of-the-art Cold Drawing Machine can produce wire with a maximum cross section reduction of up to 25 percent, depending on the alloy and its specific requirements. It consists of a receiving tank frame, push rod device, core rod lifting platform, mandrels front and back adjusting device, main drive device, body, drawing trolley and discharge conveying chain device.
For the best result, a variety of different drawing techniques can be used in sequence or at the same time. Fixed plug drawing, for example, provides a very smooth ID while maintaining a relatively low area reduction (about 25 percent). It can be performed on short benches and requires only one operator. This method is often used to achieve a narrow tolerance on the internal diameter of stainless steel pipes.
On the other hand, a floating plug drawing can be performed on a long bench with two operators to produce a very smooth ID while maintaining a tight tolerance. This method is favored for more demanding applications. It can be performed on both round and hex products with very large dimensions.
Annealing can be applied before, during (between passes) or after the drawing operation to soften the material and improve its ductility. It can also be used to adjust the microstructure, alter the mechanical properties or machining characteristics of the finished product.
The energy-power mathematical model of the drawing process is influenced by many technological parameters such as drawing speed, drawing route and die angle, as well as the alloy and its specific properties. As a result, the actual energy consumption during the drawing process may vary significantly from the calculated value. In addition, the energy required to perform a given drawing schedule depends on the ratio of wall and diameter reductions. High wall reductions with small diameter reductions tend to iron, or smooth, the ID surface while low-Q-value draws will roughen the surface. This is why it is important to design a drawing schedule based on the desired quality parameters.