What is extruded aluminum?

Extrusion, including extruded aluminum, is a process that forms a product with a fixed cross-sectional profile over its entire length. The process starts with a fixed-shape die and a length of stock (usually a round stock) that is forced through the die to conform to its shape. This requires the stock to be larger than the shape of the die, so it is simultaneously narrowed and shaped by thick steel dies and powerful presses.

A sister process to extrusion is called “drawing,” which simply pulls the stock through the die, rather than pushing it through it. This process often limits the number of consecutive extrusion steps that can be performed quickly and is usually only used for simpler extruded shapes, such as wire and round tubes.

Extrusion can be performed on hot or cold material, but hot extrusion is essential for materials with complex shapes and drastic shape changes. Extrusion can be performed on many different types of materials and is very useful for producing tubing and small or medium-sized identical parts that can be cut from a long extruded billet. The surface finish of the extruded billet is very good, and brittle materials can be easily extruded due to the support of the die and the simple forces present during the extrusion process.

What is Forging?

Forging is the process of forming metal into a specific shape using heat and pressure, through which forging transforms the raw metal without melting it. Forging is therefore often similar to the extrusion process, but forging usually only processes one part at a time.

Forging is similar to extrusion and can include the use of multi-ton presses, but can also fall under the umbrella of hammer forging and roll forging:

Hammer forging: Hammer forging uses a powerful steam, electricity, or air pressure-driven hammer to strike the workpiece quickly and repeatedly. This can quickly reshape heavy or thick metal pieces with a smaller hammer and lower overall pressure than required with a press. However, hammer forging is only used for open-die forging.

Press forging: A press applies continuous force to the top and bottom of the material to shape it. Generally, a press requires higher power input and more pressure than a hammer but can reshape the material into a variety of shapes and has more forming capabilities than a hammer. Press forging can be used with open dies (the die does not surround the workpiece) or closed dies (the die surrounds the workpiece). Closed presses are almost always used to create parts with three-dimensional shapes.

Roll Forging: Roll forging is the process of heating a material and passing it through heavy steel rolls to reduce the size and lengthen the material. Roll forging does not necessarily produce round parts; roll forging can produce square and rectangular billets, and patterns can be added to the rolls to impart that pattern to the workpiece.