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The Machinability of Aluminum Alloys

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  1. The Machinability of Aluminum Alloys

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    The machinability of aluminum alloys depends on the material’s properties and the process used. Compared to other metals, aluminum alloys are particularly well-suited to machining because they chip and shape easily. Aluminum is also highly accessible and affordable. For these reasons, aluminum alloys are a popular choice for machining applications.

    Why Is Aluminum an Ideal Material for Machining?

    In addition to its abundance and cost-effectiveness, aluminum provides a variety of benefits for machining applications. Combined with other metals and finishing processes, aluminum alloys are highly customizable to achieve nearly any desired properties. Here are some of the greatest benefits of machining with aluminum:

    • Excellent formability
    • Low-temperature resistance
    • Good strength-to-weight ratio
    • High scrap value
    • Corrosion resistance
    • Vast selection of custom finishes

    Applications for Machined Aluminum by Classification

    Pure aluminum is a very soft metal. Various alloying elements help make the metal into sheets, bars, and plates with enhanced physical properties suitable for specific applications. The Aluminum Association has categorized these properties into the following aluminum alloy series. 

    Aluminum Alloy Series 1xxx

    Consisting of 99% aluminum and 1% silicon and iron, the 1xxx series has high ductility, low mechanical properties, and good electrical and thermal conductivity. Applications for these alloys typically include heat sinks and bus bars. 

    Aluminum Alloy Series 2xxx

    Mainly alloyed with copper, the 2xxx series has excellent strength and workability. Although they lack sufficient corrosion resistance, weldability, and brazeability, these alloys can be heat-treated to produce better mechanical properties than mild steel. Aluminum alloy series 2xxx is a popular choice for home-built aircraft.

    Aluminum Alloy Series 3xxx

    Aluminum alloy series 3xxx is a general-purpose alloy not meant to be heat-treated. It provides moderate strength and good workability because manganese is its main alloying element.

    Aluminum Alloy Series 4xxx

    With the primary alloying element of silicon, the 4xxx series has a lower melting point without compromising toughness or malleability. Therefore, these alloys are ideal for welding wire. Adding an anodic oxide finish turns the metal dark gray, making it desirable for architectural applications.

    Aluminum Alloy Series 5xxx

    The 5xxx series alloys have manganese and magnesium as their main alloys, resulting in high tensile strength, excellent formability, and corrosion resistance. These properties make this alloy ideal for transportation and marine applications. 

    Aluminum Alloy Series 6xxx

    With silicon and magnesium as primary alloying elements, the 6xxx series alloys are the most versatile aluminum alloys. Heat-treated, they provide superior formability, corrosion resistance, and medium strength, which make them perfect for custom extruded shapes in piping, consumer goods, electrical parts, and architectural components.

    Aluminum Alloy Series 7xxx

    Zinc, copper, chromium, and magnesium are the primarily alloying elements in this aluminum alloy. The 7xxx series can be heat-treated to produce high strength but limited machinability. Thus, they are typically used in mold-making for the aviation, defense, automotive, and marine industries. 

    Common Aluminum Alloys for Machining

    Each aluminum series includes specific grades of aluminum alloys. Listed below are some of the most common types of aluminum alloys. Aluminum 2024, 6061, 7075, MIC 6, and 6082 are heat-treatable, while the others are not.

    Aluminum 2024

    This aluminum and copper alloy has an excellent strength-to-weight ratio and fatigue resistance. Aluminum 2024 is often used in the aerospace, automotive, and transportation industries. 

    Aluminum 6061

    Aluminum 6061 is a versatile alloy made of magnesium and silicon. This alloy is usually machined to produce structural parts, valves, truck bodies, computer parts, and aircraft components.

    Aluminum 7075

    This alloy is ductile, tough, and strong. Best used in highly stressed structural settings, Aluminum 7075 is ideal for aircraft products, sports equipment, and tooling.

    Aluminum MIC 6

    Aluminum MIC 6 is specifically developed to provide a high-tolerance, stable material for machining. Its stress-relieving, contaminant-free, and nonporous qualities make this lightweight metal ideal for electronic and laser applications. 

    Aluminum 6082

    This alloy is usually best for general-purpose applications that require an extra level of tensile strength. In fact, it’s the strongest 6xxx series alloy and is commonly found in infrastructures such as bridges and towers.

    Aluminum 3003

    Alloyed with manganese, Aluminum 3003 is ideal for cooking equipment and other household goods. 

    Aluminum 5052

    Aluminum 5052 is resistant to saltwater, so it is perfect for marine applications. This alloy combines aluminum, magnesium, chromium, and other elements to strengthen the material against corrosion and improve its workability for other heavy-duty industries like energy and aerospace.

    Aluminum Alloy Machining by Superior Metal Shapes 

    Superior Metal Shapes offers full-service aluminum machining services, from CNC machining to sawing to cutting to deburring. Secondary services include anodized painting, heavy etching, buffing, and military-grade finishing. Our ISO 9001 and AS9100 certified facility ensures the highest quality for every project. Contact us or request a quote to see how our capabilities can serve you.