Aluminum is a metal with a wide range of applications, and since its introduction to manufacturing, it has transformed almost every industry you can think of. Not only is it one of the lightest yet strongest materials known, but it also offers a wealth of diversity to manufacturers and engineers due to the sheer number of alloys available. Even today, new high-performance alloys are introduced to the market every year.
There are two aluminum alloy numbering systems, and it’s a common misconception to assume these are just two different aluminum classification systems. There are significant differences between these two types of aluminum and it is important to understand them.
The numbering system most of us are familiar with for classifying aluminum alloys is the four-digit system, which is used to classify wrought aluminum alloys as well as many cast sheet products. In contrast, alloys used to produce castings use a different classification system, although they also use 4 digits with a decimal between them. It is important to note that cast alloys are usually listed with only three digits since the number after the decimal point is usually zero.
For example, 7075 is a common wrought aluminum alloy, while A380 is a popular cast aluminum alloy.
Advantages of Wrought Aluminum Alloys
Wrought aluminum alloys are made by melting pure aluminum ingots while adding specific amounts of desired alloying elements. The metal is then formed into billets or slabs that can be forged, rolled, or extruded into the desired shape. Depending on the alloy, it may also be heat-treated to improve its mechanical properties.
Depending on the amount of wrought aluminum used in industrial production, there are several main advantages over casting aluminum into the desired part.
Due to the casting process, cast aluminum parts tend to have lower tensile strength and lose some of the natural properties of the alloy. This is due to naturally occurring casting defects such as porosity and alloy segregation.
Wrought aluminum alloys tend to maintain their mechanical properties because the forming process performed is inherently mechanical. While cast aluminum is generally cheaper and more cost-effective, lower tensile strength and other disadvantages make it less desirable in many applications.
Among its many advantages, wrought aluminum products offer many good mechanical properties compared to cast products. They maintain structural integrity more efficiently, exhibit a good surface finish, and are better suited to aluminum processing techniques such as extrusion, welding, and machining.
This diversity can also be a source of confusion among consumers and the uninformed. Knowing which specific alloy to choose is critical to the success of any project and application; with so many options to choose from, it’s easy to make a mistake. This is especially true when differentiating between forged products and cast aluminum parts.
