Aluminum and its many alloys have transformed the way we build, move, and communicate. It’s nearly impossible to name an industry that hasn’t been impacted in the past century by the introduction of aluminum alloys.
There is a certain paradox about aluminum that helps explain why there are so many alloys on the market today. On the one hand, it is one of the most abundant elements found on Earth—the third most common element in the Earth’s crust after oxygen and silicon. Yet it was only discovered relatively recently compared to other elements, because in its purest form it is highly reactive and not that strong, and thus easily combines with other minerals to form ores such as alum and bauxite.
That’s why aluminum needs to be alloyed with other elements, such as zinc, magnesium, copper, tin, and silicon. For manufacturers, this means it’s important to be well versed on the various aluminum alloys, what their unique properties are, and which alloys are best suited for which applications. It’s also why it pays to partner with an experienced supplier who understands the alloy selection process.
What is meant by the term “common alloy”?
An aluminum alloy is a grade of aluminum that has been mixed with other elements to alter the chemical structure in a desirable way. The most common alloying elements for aluminum include copper, magnesium, manganese, silicon, tin, and zinc.
The term “common alloy” has been applied to three families of aluminum alloys, all of which fall in the category of non-heat treatable grades. They are not alloyed with elements that allow for hardening through thermal processing; these grades must be cold worked through the rolling process to improve their mechanical properties.
Common alloys include the 1xxx, 3xxx and 5xxx series of aluminum grades.
What are the different series of common alloys?
The 1xxx series of alloys are 99% pure aluminum. They are weaker than other alloys, but it is possible to work harden them to some degree. This class is known for its excellent electrical conductivity, corrosion resistance and workability.
The 3xxx alloys use manganese as their main alloying element. These alloys tend to be stronger than other non-heat treatable alloys and are known for being workable with good corrosion resistance. Many alloys in this category are suited for deep drawing, welding or brazing applications.
Magnesium is the primary alloying element for 5xxx series aluminum alloys, along with small amounts of manganese. They are strain-hardenable, weldable and so corrosion resistant they are used in marine applications. They are also the strongest of the non-heat treatable alloys.
Standard common alloy grades
The high electrical conductivity of the 1xxx series, consisting of almost pure aluminum, makes it prime for widespread use in the electrical transmission and power grid industry. 1350 is a popular in the electrical industry and 1100 is widely used in the food packaging/processing and chemical industries.
The most popular of the common alloys is 3003, which is the most widely used of all aluminum grades. It is a commercially pure aluminum, with manganese added to increase its strength, while retaining its corrosion resistance and workability. It’s commonly used in cooking utensils, storage tanks, decorative trim and many more applications.
Another extremely popular alloy is 5052, which is known for being extremely versatile. It has the best corrosion resistance of the common alloys and excellent mechanical properties; it is workable and can be welded. As mentioned previously, it is widely used in marine applications due to its corrosion resistance.