When deciding on a metal to use for specific applications, one must have a good understanding of each metal’s characteristics. Therefore, it is not a matter of a coin toss or a childhood game, but instead a matter of knowledge of each metal and its alloys.
“Ferrous” means a metal or alloy that contains iron. The term “nonferrous” therefore means a metal that contains no iron. Therefore aluminum and copper, two metals which don’t contain iron, are considered nonferrous. These two metals, are usually employed in creating metallic alloys, rather than cast as pure metal.
Aluminum Investment Castings
The nonferrous metal most commonly used in investment casting is aluminum. This versatile lightweight metal is used for a wide variety of applications. Aluminum is used in creating various parts for a number of industries, including the aerospace manufacture, automotive industry and military equipment.
Of course, the base metals for aluminum and copper investment castings are aluminum or copper. While these metals can be cast as a pure metal, that’s not usually how they are cast. Most of the time, they are cast as the main metal in an alloy.
Alloys are created when a base metal is combined with another metal or element. Some of the most common elements used in creating aluminum alloys are: silicon and magnesium. Since pure aluminum is more susceptible to corrosion and stress-created weaknesses, the addition of these other elements overcome those weaknesses. Aluminum alloys are resistant to corrosion and strong enough to be used as components in some very vital applications: space exploration, military superiority and automotive safety
Copper Investment Castings
Another nonferrous metal used in investment casting is the reddish-gold copper. Copper is a metal that even in its pure form resists both oxidation and corrosion. For this reason copper is often combined with other metals when the end product is going to be used in harsh environments where corrosion and oxidation could be an issue. Additionally, the conductive properties of copper make it a valuable metal for items used in electronics and electrical applications.
Beryllium is the element most often combined with copper to create a copper alloy. Used in investment casting the addition of beryllium provides copper with both strength and a hardness not otherwise found in pure copper. This makes copper alloy castings not only strong and hard, but also very conductive as well as being corrosion resistant and fatigue. Some of the components created with copper-beryllium are spot-welding electrodes, springs and electrical contacts.
Aluminum and Copper Investment Castings
Aluminum and copper are the two most common malleable, nonferrous metals used in investment casting. While they are both nonferrous, the may be the only commonality between the two metals. There are, in fact, many differences between the two, so it is very important one understand the properties of these metals when choosing a metal for a particular application.
