Aluminum Alloys used in the CNC Machine Shop
Introduction
Aluminum alloys offer a perfect blend of lightweight versatility, strength, and machinability. The choice of the right alloy plays a pivotal role in determining the effectiveness your parts will have in their given application. In this blog post, we embark on a journey through the world of commonly machined aluminum alloys, exploring their unique properties and applications.
Aluminum 6061: The Go-To Alloy for CNC Machined Parts
Composition:
Aluminum (Al): 97.92%
Magnesium (Mg): 1%
Silicon (Si): 0.6%
Copper (Cu): 0.28%
Chromium (Cr): 0.2%
PhysicalProperties (T6):
Rockwell 60 HRB Hardness
Ultimate tensile strength of 45 ksi
Yield tensile strength of 40 ksi
Shear Strength 30 ksi
Fatigue Strength 14 ksi
Applications:
General use for metal components that do not require the strength of steel
Aluminum 6061 reigns supreme as the go-to choice for engineers and machinists due to its optimal blend of strength and machinability. 6061 is affordable, readily available, and quick to machine. This makes it a very cost-effective metal for machined parts. It is also heat-treatable, easily welded, and partially resistant to corrosion. It is by far the most common aluminum alloy used in machined parts.
Aluminum 7075: High-Strength Alternative Alloy
Composition:
Aluminum (Al): 90.07%
Zinc (Zn): 5.6%
Magnesium (Mg): 2.5%
Copper (Cu): 1.6%
Chromium (Cr): 0.23%
Physical Properties (T6):
Rockwell 87.5 HRB Hardness
Ultimate tensile strength of 83ksi
Yield tensile strength of 73 ksi
Shear Strength 48 ksi
Fatigue Strength 23 ksi
Applications:
General use for metal components that require the strength of low-grade steel, but the light weight of aluminum
When the need for high strength takes center stage, engineers and machinists turn to Aluminum 7075. This alloy has good machinability and corrosion resistance but is not very weldable. 7075 is not as affordable or readily available as 6061 but is comparable in its ease of machining. Its exceptional strength and fatigue resistance make it a powerhouse in aerospace and high-performance sports equipment.
Aluminum 2024: The Aerospace Workhorse
Composition:
Aluminum (Al): 93.5%
Copper (Cu): 4.4%
Magnesium (Mg): 1.5%
Manganese (Mn): 0.6%
Physical Properties (T4):
Rockwell 75 HRB Hardness
Ultimate tensile strength of 68 ksi
Yield tensile strength of 47 ksi
Shear Strength 41 ksi
Fatigue Strength 20 ksi
Applications:
Aerospace components (Valves, pistons, gears, etc)
Structural applications (Bolts, Nuts, etc)
Aluminum 2024 is valued for its high strength and fatigue resistance, however, it is less weldable and resistant to corrosion than other alloys. It finds a place in structural components and aircraft skin due to its reliability under stress.
Aluminum 5052: The Corrosion-Resistant Contender
Composition:
Aluminum (Al): 97.25%
Magnesium (Mg): 2.5%
Chromium (Cr): 0.25%
Physical Properties (H32):
Rockwell 16 HRB Hardness
Ultimate tensile strength of 33 ksi
Yield tensile strength of 28 ksi
Shear Strength 20 ksi
Fatigue Strength 17 ksi
Applications:
Marine applications (boat hulls, buoys)
Sheet metal fabrication (automotive panels)
Aluminum 5052 takes the stage when corrosion resistance is paramount. Its ability to withstand harsh environments makes it a top choice for marine applications. This alloy is most often used in sheet metal forming but can be found in plates for machining applications.
Conclusion
Each alloy brings its unique set of advantages to the table. From the versatility of Aluminum 6061 to the high-strength prowess of Aluminum 7075, the world of machined aluminum alloys is diverse and dynamic. Choosing the right alloy depends on the specific requirements of the application, and with ongoing innovations in alloy development, the possibilities for machining excellence continue to expand.
Do you need CNC Machined Aluminum Parts?
OpenAI. (2023). ChatGPT [Large language model]. https://chat.openai.com
*Physical Property values based on Machinery’s Handbook 31