What is the difference between extruded and cold worked aluminium?

What is cold worked aluminium?

Extrusion is usually carried out at high temperatures, when aluminium is more easily formed, whereas cold working is carried out at room temperature. When cold worked, the outer diameter tolerances are very close. A common form of cold finishing is drawing.

In the production of aluminium sheets or other aluminium products, drawing also uses dies to reduce the diameter of the material. The bars have a small end diameter and are placed through the drawing die and then pulled out using a gripper. Although drawing can be carried out at high temperatures, it is usually carried out at room temperature.

Cold working depends on the flow and stretching of the aluminium. The material reduction process hardens the material and changes its physical and mechanical properties. This also improves the surface finish of aluminium sheets or other aluminium products.

What is the difference between extruded and cold worked aluminium?

The main advantage of standard aluminium extrusion is that aluminium is more easily formed at higher temperatures. This equates to a faster production rate, which is why extruded aluminium sheets or other aluminium products are often cheaper than cold worked aluminium. Faster production also results in shorter lead times to market.

The downsizing process involving cold-worked production produces tighter dimensional tolerances, which is beneficial when used in conjunction with the use of close-fitting collets in high-speed precision CNC machining centres. It also improves the mechanical and physical properties of the material; this improves cutting performance and produces smaller chips during machining, resulting in faster removal from the working area of the cutting tool.

So, the benefits of extruded aluminium sheet or other aluminium products versus cold worked aluminium each depend mainly on their specific application scenario.