Aluminum is one of the most versatile metals on the planet, valued for its high strength-to-weight ratio, workability and corrosion-resistant properties. Pure aluminum is often combined with other alloying elements to enhance specific qualities and improve its uses. The Aluminum Association has classified these new aluminum alloys into different grades.
Smelting an aluminum ingot with specific additives produces different types of aluminum alloys that receive 4-digit classification codes. The first digit identifies the primary alloying element, dividing the alloys into the 1000 series, 2000 series, 3000 series and so on up to 7000. The second digit identifies modifications to the alloy. The third and fourth digits are arbitrary and serve as tags to differentiate alloys within the same series.
The aluminum grades and their corresponding elements are as follows:
Each aluminum alloy series has various advantages that make them useful for different applications. Let’s look at the different grades of aluminum and the applications they can serve.
The 1000 series is 99% aluminum and does not contain any significant amounts of alloying elements. It is extremely corrosion-resistant and has high electrical and thermal conductivity. However, the 1000 series is not as strong as other aluminum alloys.
Because it’s almost exclusively composed of aluminum, the 1000 series is relatively soft and ductile. It’s most often used for applications that need an alloy that can be shaped into different products, such as chemical equipment, dials, railroad tank cars and electrical conductors. The most common grade in the 1000 series is aluminum 1100, which offers the highest mechanical strength.
The 2000 series uses copper as the alloying element, adding additional strength and hardness to the aluminum. However, a susceptibility to shrinkage cracks during the hardening process makes alloys in the 2000 series somewhat challenging to weld. Aluminum in the 2000 series is often used for truck wheels and suspensions and in the aerospace industry.
Aluminum 2024 is one of the most well-known aluminum alloys in the 2000 series. It has a high strength-to-weight ratio and fair corrosion resistance.
Manganese is the main alloying ingredient in the 3000 series. Manganese provides higher strength that the alloy can maintain at a wide range of temperatures. Aluminum in the 3000 series is also very formable and ductile, with moderate strength and corrosion resistance. However, while you can harden it using coldworking, it is not heat-treatable.
Aluminum 3003 is the most widely used alloy in the 3000 series. It is a great general-purpose aluminum and is commonly used in vehicles and electronics. While it is also often used in cookware like utensils and pot lids, its lack of heat resistance makes it unable to handle oven temperatures.
The 4000 series create an aluminum alloy by adding silicon. The 4000 series usually also contains small traces of copper and magnesium. Adding silicon to aluminum lowers its melting point, which makes aluminum in the 4000 series ideal for welding. The 4000 series is often used in architectural applications. Examples of alloys in the 4000 series include:
Aluminum in the 5000 series contains magnesium. Like the 3000 series, the 5000 series is not heat-treatable and must be treated via coldworking. It offers moderate-to-high strength, solid weldability and good corrosion resistance. The 5000 series is usually used in appliances, automotive parts and structural pieces like beams and tubes.
Aluminum 5052 has excellent thermal conductivity, which makes it widely used for heat exchangers and cooking utensils. Other widely used alloys in the 5000 series include aluminum 5083 and aluminum 5005.
The 6000 series adds both silicon and magnesium, giving the alloy medium strength and solid formability, weldability and corrosion resistance. Aluminum in the 6000 series can be heat treated to increase its strength even more, making it ideal for structural and architectural applications.
There are two popular grades in the 6000 series — aluminum 6061 and aluminum 6063:
Zinc is the alloying element in the 7000 series. Aluminum alloys in the 7000 series are some of the strongest and most durable. This series offers very high corrosion resistance and is also heat-treatable, though it is usually not weldable. Aluminum in the 7000 grade is often used for airframe structures, mobile equipment and parts that experience high stress.
Aluminum 7075 is an extremely strong aluminum grade. It can withstand periods of high stress and is even stronger than the 6061 grade. Besides its use in the aerospace industry, 7075 is also used in bicycle parts and competitive sporting equipment.
Combining aluminum with an alloy compound can change it drastically. When you’re choosing an aluminum grade for your project, consider the following characteristics:
Knowing the characteristics you need will help you choose the correct aluminum alloy for your application. For example, if you are creating parts for marine applications and need a moderate-strength alloy that is formable, weldable and corrosion-resistant, you might choose aluminum 5052.
Pennex Aluminum Company has been a leader in the aluminum fabrication industry for decades. As a member of the Metal Exchange Corporation, we have the resources of a large company while retaining the personalized feel of a small business.
Our goal is to be your one-stop shop for all things aluminum. When choosing between the different grades of aluminum for your next project, we can help you figure out which one will best serve your needs. For more information, contact us online today!
