A Quick Comparison of Aluminum Alloys for Machining
Dec 10, 2019
Although CNC machining is a versatile manufacturing process compatible with a wide range of materials, it is virtually synonymous with aluminum, a widely used metal available in numerous grades. Aluminum is highly machinable and relatively affordable, and its many alloys are suited to myriad machining applications, from rigid architectural components to aerospace parts and beyond.
RapidDirect gives the option of some 20 aluminum alloys for its CNC machining services (see our full material list for details), all of which offer distinct and unique advantages. But while that range of options gives you huge flexibility when embarking on a machining project, it does make it harder to narrow down the best aluminum alloy for the job.
Which aluminum alloys offers the best value? which is most resistant to chemicals or heat? Which has the highest tensile strength? And eventually, which alloy is best for your machining project?
This guide attempts to provide a quick comparison of five of the most popular aluminum alloys, highlighting their composition, common applications and the industries in which they are regularly put to use.
Definition: What are alloys?
An alloy is a metal mixed with either other metals or non-metallic elements. Aluminum alloys are materials largely consisting of aluminum, but with other elements such as iron, copper and magnesium mixed in.
Depending on their composition, different aluminum alloys are suitable for different applications. The mixture of other elements affects an alloy’s physical properties, including its strength, ductility and corrosion resistance, and these properties can help a company decide whether the material is suitable for a given part.
Aluminum grades can be broken down into three groups: commercially pure aluminum, heat-treatable alloys and non-heat-treatable alloys. Since commercially pure aluminum is less regularly used in CNC machining (we can, however, machine parts using Aluminum 1060), this article focuses on five alloys from the latter two groups.
Categorize: Common types of aluminum alloys
There are many ways to categorize different types of aluminum, a common practice is by aluminum grade such as 1xxxx, 2xxx, to 7xxx, the difference lies in the composition, which as a result, infects the properties of different aluminum alloy. In this article, however, we are not going to talk about all series of aluminum alloys, we are introducing the common subtypes by it heat treatment feature.
1. Heat-treatable alloys
Aluminum 2024, one of the more widely used of the ‘duralumin’ aluminum alloys in the 2xxx group, is a copper-alloyed material with an excellent strength-to-weight ratio. It is resistant to fatigue but fairly susceptible to corrosion.
Tensile strength: 68,000 psi
Major alloying elements: Copper
Industries: Automotive, aerospace, transportation
Products: Car parts, aircraft parts, transport vehicle parts, structural parts, electronics
Aluminum 6061 is the most widely used alloy in the 6xxx series and one of the most versatile of all machinable alloys. By CNC machining aluminum 6061, it is possible to make a wide range of products, including electronic and aircraft parts.
Tensile strength: 45,000 psi
Major alloying elements: Magnesium, Silicon
Industries: General manufacturing, aerospace, consumer goods, architecture
Products: Structural parts, steps, platforms, covers, truck bodies, valves, pipes, aircraft parts, computer parts, electronics
Commonly used for highly stressed structural applications, Aluminum 7075 is often found in structural aircraft parts, as well as sports equipment, tooling and more. 7075 is heat-treatable, ductile, strong and tough, but can also become brittle.
Tensile strength: 83,000 psi
Major alloying elements: Zinc
Industries: Aerospace, transportation, sporting goods
Products: Aircraft parts, transport vehicle parts, bicycles, golf clubs, weapons
2. Non-heat-treatable alloys
The most widely used aluminum alloy (across all manufacturing processes), Aluminum 3003 is a near-pure aluminum alloyed with Manganese. It is frequently used for household goods like cooking equipment.
Tensile strength: 13,000 psi
Major alloying elements: Manganese
Industries: Household goods, chemicals
Products: Cooking utensils, kitchen equipment, tanks, siding and trim, roofing, chemical equipment
Strong, workable and corrosion-resistant, Aluminum 5052 — made with magnesium and chromium, amongst other components — is widely used in marine applications because of its resistance to salt water. It is also the strongest non-heat-treatable alloy available.
Tensile strength: 33,000 psi
Major alloying elements: Magnesium, chromium
Industries: Marine, aerospace, architecture, electrical, oil and gas
Products: Marine transport parts, heat exchangers, aircraft parts, fuel lines, fuel tanks, panels, household appliances, commercial and heavy-duty cooking equipment
Guideline: Choosing an aluminum alloy
Knowing the different types of aluminum alloys for machining isn’t enough, we need to take one step further and learn which aluminum alloy we should choose for machining application. Below are the most important factors to consider:
- Formability / Workability
- Corrosion resistance
- Heat treatment
- End-use applications
To save you some time, we have sorted out a aluminum grades chart for a quick reference of your ideal aluminum alloy:
|Formability or Workability||Weldability||Machining||Corrosion Resistance||Heat Treating||Strength||Typical Applications|
|Alloy 1100||Excellent||Excellent||Good||Excellent||No||Low||Metal Spinning|
|Alloy 2011||Good||Poor||Excellent||Poor||Yes||High||General Machining|
|Alloy 2024||Good||Poor||Fair||Poor||Yes||High||Aerospace Application|
|Alloy 3003||Excellent||Excellent||Good||Good||No||Medium||Chemical Equipment|
|Alloy 5052||Good||Good||Fair||Excellent||No||Medium||Marine Applications|
|Alloy 6061||Good||Good||Good||Excellent||Yes||Medium||Structural Applications|
|Alloy 6063||Good||Good||Fair||Good||Yes||Medium||Architectural Applications|
|Alloy 7075||Poor||Poor||Fair||Average||Yes||High||Aerospace Applications|
After reading the article, we hope that you can tell the definition and types of aluminum alloy. However, if you’re not sure about what kind of aluminum alloy suits your parts or prototypes — or if you think your part should be machined from an alloy not on the list — you can request an instant quote and get in touch with us.
RapidDirect offers a wide choice of nearly 100 materials for CNC machining, sheet metal fabrication, injection molding services, far beyond the very limited ones mentioned here. When getting a rapid quote from us, you can select one of these alloys drop the drop-down list of materials, or choose one of many non-aluminum materials instead.
With this information, we can help you decide on the best material for the job, ensuring that your parts get made exactly as you want them. Upload your CAD files and have a try today!
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