Understanding Different Aluminum Alloys Used in Extrusion

Aluminum extrusion is a manufacturing process that involves forcing aluminum alloy through a die to create a desired cross-sectional shape. The resulting extruded aluminum products are widely used in various industries, including construction, automotive, and consumer goods. Understanding the different aluminum alloys used in extrusion is crucial for selecting the most suitable material for a specific application.

Alloy Temper and Strength

The temper of an aluminum alloy refers to the specific heat treatment that it undergoes after extrusion. Different tempers result in varying strengths and characteristics. For example, the 6000 series alloys, such as 6061 and 6063, exhibit high strength and good weldability in the T6 temper, which involves solution heat treatment followed by artificial aging.

Corrosion Resistance

The composition of an aluminum alloy significantly influences its corrosion resistance. Alloys containing higher levels of magnesium and manganese, such as the 5000 series (5052 and 5083), provide excellent resistance to seawater corrosion. On the other hand, alloys with higher copper content, such as the 2000 series, exhibit reduced corrosion resistance in marine environments.

Formability and Machinability

The formability of an aluminum alloy refers to its ability to be cold-worked or shaped without cracking. Alloys with high ductility, such as 1000 series aluminum (1050 and 1060), are easily formed and bent. Machinability refers to the ease with which an alloy can be machined. Alloys with low silicon content, such as 6061, exhibit good machinability, making them suitable for precision machining operations.

Comparison of Common Aluminum Alloys

The following table summarizes the key properties of some of the most commonly used aluminum alloys in extrusion:

| Alloy | Temper | Strength | Corrosion Resistance | Formability | Machinability |

|————|———|———|——————–|————|————-|

| 1050 | O | Low | Good | Excellent | Excellent |

| 5052 | H32 | Medium | Excellent | Good | Good |

| 6061 | T6 | High | Good | Fair | Fair |

| 6063 | T5 | Medium-High| Good | Good | Good |

| 7075 | T6 | High | Fair | Fair | Fair |

Considerations for Alloy Selection

When selecting an aluminum alloy for extrusion, factors such as strength, corrosion resistance, formability, machinability, and intended application must be considered. For demanding applications requiring high strength, alloys like 6061 or 7075 are suitable. For applications in corrosive environments, alloys like 5052 or 5083 provide excellent protection. For intricate shapes or cold-working, alloys with good formability, such as 1050, are preferred. Finally, alloys with good machinability, such as 6061, minimize machining costs and ensure precise tolerances.