If you opt for aluminum, you have to go for the most proper one. Aluminum is not just the same; it has its own different alloys. All of these have distinct properties. Learning these codes is like unlocking a new language.
Learning them makes it possible to tell the precise material that you require. Aluminum sheet is the most commonly used form of aluminum and is available in a myriad of grades aimed at different commercial requirements.
How to Interpret the Aluminum Alloy Grading System
Aluminum alloys are associated with a four-digit identifier. Commonly these include 3003 or 5052. The first digit reveals what the main alloying element with aluminum is. The element is basically the one that gives that alloy its first properties.
The series that are most commonly used for sheet metal are provided below:
- 1xxx Series: This is pure aluminum (99% or more) commercially. It provides excellent resistance to corrosion and is really easy to form. Although the draw-back is it is very low in strength.
- 3xxx Series: Manganese is the primary alloying element. This offers a slight increase in strength and maintains good formability. It serves as an excellent general-purpose alloy.
- 5xxx Series: The main alloying element is magnesium. This series resists corrosion, especially from saltwater, really well. This is coupled with the fact that it is also strong and easy to weld.
- 6xxx Series: These alloys are made of a combination of magnesium and silicon. This means that they can be made stronger by means of heat treatment. They have a good combination of strength, corrosion resistance, and formability.
What Does the Temper Designation Mean? (-H14, -T6, etc.)
After the four-digit grade for the aluminum, there will be a letter and number on what the temper is. Examples are -H14 or -T6. This is an abbreviation for the temper designation. The number appears indicating the strength and hardness of the alloy.
Temper is largely obtained by two processes. These are work-hardening and heat-treatment.
- -O: This is the aluminum that has been annealed or it is as soft as it can be. It is really in the best workable state.
- -H: This means that the aluminum has been strain-hardened (or work-hardened). The numbers that follow indicate the degree of hardening. For example, H14 is half-hard.
- -T: This means the aluminum has been heat-treated to increase its strength. The number that follows indicates the type of heat treatment applied. T6 is one of the most common tempers for structural parts.
Common Grades in Action
To sum it all up, here are the most common aluminum sheet grades and their applications:
- 3003-H14: This is the main player among aluminum sheets. It is a go-to choice for general purpose applications such as fan blades, ductwork, and siding. It possesses decent formability and strength.
- 5052-H32: This is the grade that is known for its great corrosion resistance. Marine environments are a good example. It is quite often used to cover hulls, fuel tanks, and for metal encasements.
- 6061-T6: This alloy is of structural nature and has been heat-treated for high strength. It gets used where lightness and strength are both important. The examples of that might be aircraft parts, bicycles and structural supports.
A Fabricator’s Guide: How to Choose the Right Aluminum Sheet
It’s one thing to know the grades. But selecting the appropriate one for your unique project is a whole different thing. At some point, we ask the right questions that we are aware of before our clients even tell us which aluminum sheet they require.
We effectively constantly ask our clients five questions before a material is ordered. This is done to ensure that the finest fit for the project is gotten. It also helps in avoiding mistakes that are usually common. These questions will help you in making the right materials selection.
1. Environment
In what environment will your part be used? Is it going to be outdoors, exposed to rain and the sun? Will it be adjacent to sea salt or in a strictly controlled indoor setting?
The environmental factor is the primary contributor to corrosion. In case your part will be in a heavy industrial or marine setting, then a 5xxx series alloy is always matching somewhat like a 5052. However, for indoor use a 3003 alloy is probably sufficient and also more affordable.
2. Forming
Does your design allow for simple bends? Or does it need complex curves and deep draws? The more you have to shape the metal, the more it needs to be formable.
For designs with very tight bends, a softer temper is needed. An -O temper (annealed) or a lower -H temper is ideal. Alloys in the 1xxx and 3xxx series are also more formable than the stronger 5xxx and 6xxx series alloys.
3. Strength
Is the part a structural component that will bear a load? Or is it just a cosmetic cover or enclosure?
If your part needs to be strong, a heat-treatable alloy like 6061-T6 is the clear winner. It offers much higher strength than the other common sheet alloys. If strength is not a major concern, you can use a less expensive and more workable alloy like 3003-H14.
4. Assembly
How will the final product be put together? Will it be welded? Or will it be assembled with screws and rivets?
Not all aluminum alloys weld well. The 5xxx series alloys are known for their excellent weldability. The 6xxx series alloys can also be welded. But they lose some strength in the area around the weld. If welding is a key part of your assembly, choose your alloy carefully.
5. Finishing
What will the final surface of your part look like? Do you plan to paint it, powder coat it, or anodize it?
Anodizing is an electrochemical process. It creates a durable and decorative finish on aluminum. The 6xxx series alloys are excellent for decorative anodizing. They create a clear, attractive finish. Other alloys can be anodized, but the results may be less consistent.
