In an ideal world, you’d have the knowledge of a metallurgist and hands-on machinist experience anytime you needed to choose the right grade of aluminum for a specific machining process. The inherent characteristics of aluminum make it relatively easy to machine, but the various aluminum grades do differ in their overall machinability and use. Some of the most commonly used grades in machining are MIC 6, and 2024, 5083, 6061, 7050, and 7075 aluminum alloys. 

Ultimately, the aluminum grade you choose is directly related to the purpose or application of the component being machined. Before choosing the aluminum grade that’s right for your machining process, let’s review the key characteristics and machinability of these common aluminum alloys and their typical applications. 

2024 Aluminum Alloy

Characteristics: High strength with excellent fatigue resistance but poor corrosion resistance.

Machinability: Produces uniform chips, but prone to chipping at the end of heavy cuts where the tool breaks out. To prevent this, modify the toolpath to ease the tool exit. Machines to a high finish.

Applications: Aerospace—whenever a good strength-to-weight ratio is required or the component is under tension

5083 Aluminium Alloy

Characteristics: This aluminum alloy performs well in extreme environments such as seawater and industrial chemicals, highest strength of the non-heat-treatable aluminum alloys, lower hardness, and retains outstanding strength after welding.

Machinability: High strength limits the complexity of machined components. Poor machinability results in surface roughness.

Applications: Marine vessels, rail cars, pressure vessels, dump truck bodies. Not recommended for use in temperatures over 150°F (65°C).

6061 Aluminium Alloy

Characteristics: The most versatile heat-treatable aluminum alloy. These aluminum alloys have good corrosion resistance. 

Machinability: These machinable alloys have excellent machinability. The harder the temper, the easier the machining. 

Applications: Structural and general fabrication. One of the best aluminum alloys.

7050 Aluminium Alloy

Characteristics: High toughness, strong mechanical strength with good stress corrosion cracking resistance even at subzero temperatures. Heat treatable.  

Machinability: 7050 aluminum alloys have better machinability than 7075, though 7075 has less burr formation and better surface quality.

Applications: Aerospace and heavy plate components.

7075 Aluminium Alloy

Characteristics: One of the highest strength aluminum alloys available, extremely stiff, excellent strength-to-weight ratio, heat treatable, and lower corrosion resistance.

Machinability: Fair, in comparison to 6061 aluminum alloy. Smooth but dull gray finish.

Applications: Aerospace, highly stressed components, bike frames, etc.

MIC 6

Characteristics: Outstanding dimensional stability and flatness, very low internal stresses, and minimal contaminants and porosity. 

Machinability: Excellent machining processes, allows high-speed metal removal with minimum distortion, and produces small, uniform chips. 

Applications: Base plates, templates, jigs, gauges, molds, dies, routing tables, chip printers, vacuum chucks, electronics, and automotive and aerospace components.

Choosing an Aluminum Grade That’s Right for Your Machining Process: At a Glance

Because of its versatility and ease of machinability (relative to ferrous metals and alloys), aluminum is used in just about every machine shop around the world—and certainly right here at our home in the San Francisco Bay Area. With the right techniques, it can be machined quickly and efficiently. 

• MIC 6 – Excellent (Cast plate)
• Alloy 6061 – Good Machinability (T4 and T6 tempers)
• Alloy 7050 – Fair Machinability (Better than 7075)
• Alloy 7075 – Fair Machinability (Compared to 6061)
• Alloy 2024 – Fair Machinability (Prone to chipping)
• Alloy 5083 – Poor Machinability (Surface roughness)

All grades of aluminum are machinable when proper cutting tools, feeds, speeds, and techniques are carefully matched to the characteristics of the alloy and design of the component being machined. With the right aluminum grade, you can optimize the performance of machined components, achieve the required dimensions, strength, and weight, and cost-effectively manufacture quality components.

We Have the Right Aluminum Grade for Your Machining Needs: Local and Nationwide

Industrial Metal Service offers a wide range of the most frequently used aluminum alloys. From our warehouse in San Jose, CA in the San Francisco Bay Area, we can provide scheduled delivery to meet your production schedules or rapid delivery when you need aluminum in a hurry. We offer certified new metal stock as well as verified metal remnants at unbeatable prices. Additionally, our cut-to-size sawing services take care of cutting your order to the required sizes and we ship nationwide—quickly—for your convenience. 

When you’ve chosen the aluminum grade that’s right for your machining process, or if you need some assistance in making that choice, give us a call and we’ll take care of your order.