There are your “normal” metals and then there are “exotic” metals. What’s the difference and why are certain metals used for some applications while exotic metals are required for others?
“Normal” metals (all the exotics are alloys) have processes that are generic, well known, and generally available to anyone interested enough to use them. These are the standard grades of steels and stainless steels as well as aluminum, copper, brass, and others. The standards which define the identity of the alloys can be confirmed by most any compliance lab.
Exotic metals are alloys created using highly specialized processes controlled by a relatively small group of experts and are difficult to produce without highly-specialized equipment and knowledge. The standards they follow often require specialized compliance labs equipped specifically for the alloy in question. A lot of exotics are developed to solve very specific problems.
Exotic metals are more costly to manufacture and process due to the high temperatures required for heating and shaping parts. Some of the more well-known exotic metals include titanium, molybdenum, and super alloys. Machining exotic alloys is often difficult, with a dizzying array of coating grades required for the cutting tools. Post-machining processes are often difficult as well. Precipitation-hardening is used with some of the nickel super-alloys and can be a challenge.
Let’s take a closer look at some of the more commonly-used exotic metals:
Titanium is often used in fighter jet and car racing applications. It is nearly as light as aluminum, yet is stronger than steel. It’s not used much in everyday applications because it tends to deform when it comes into contact with other metals. Titanium must be heated to around 3,000 degrees Fahrenheit when processed. It must also be kept in an airtight environment.
Molybdenum is known for its strength and electrical conductivity. It is often used in lighting, medical equipment, thermal spray coatings, and in military applications. This metal has been in use since the early 1920s and is commonly used in many of today’s manufacturing applications.
Hastelloy is a super alloy that is desirable for its high strength, ability to tolerate extremely high temperatures, and resistance to corrosion. Due to its ability to withstand high temperatures, super alloys such as Hastelloy are often used in the turbines of jet engines.
Fasteners formed from exotic metals are typically used in harsh conditions such as marine environments or ones that require exposure to corrosive chemicals. If standard metals were used in these situations there is a greater risk for early degradation and massive structural failure. Operating in these kinds of extreme conditions will often more than justify the use of more expensive exotic metals.
To learn more about fasteners manufactured from exotic metals, contact the fastener experts here at Electronic Fasteners.