When you are interested in fastening a product that will be exposed to high temperatures, you often need to pay keen attention to the types of fasteners you will use. This is because this will affect the longevity of the product, as well as how long it’s going to last. In order to do this, […]

When you are interested in fastening a product that will be exposed to high temperatures, you often need to pay keen attention to the types of fasteners you will use. This is because this will affect the longevity of the product, as well as how long it’s going to last. In order to do this, you will need to understand how fasteners behave when exposed to high temperatures, and the features that will make them last much longer as well.

How high temperatures affect fasteners

high temperature applications fasteners
When you expose many regular fasteners to high temperatures, one of the challenges you will face is oxidation. Most people think that the main problem you will face is having the fasteners melt, but most metals will not do so when exposed to temperatures of around 1000 degrees Fahrenheit or lower.
Of course, this is unless they are made of a material that is particularly soft. In addition to that, the other issues you may have a problem with include rapid expansion of the fasteners. This leads to them increasing the diameter of the holes they are in. When they cool down, they are likely to then contract and become loose. When this happens several times, they could even fall out of place particularly when exposed to vibration as well.

The different alloys you can use

In order to use fasteners for high temperature environments, you will generally find it necessary to use alloys. This way, you can combine the benefits of various metals in order to make the resultant fastener more resistant to heat and oxidation. Some of the most commonly used ones include:

  • A-286: This is an alloy of iron, nickel and chrome. It has excellent mechanical properties, and is very resistant to oxidation and high temperatures. The only downside to using it is the fact that it will only retain these properties up to a temperature of around 1300 degrees Fahrenheit. Above this, the metal is likely to start oxidizing. When exposed to even higher temperatures, it will eventually melt.
  • Nickel: There are many types of nickel alloys including Inconel socket head cap screws. Depending on the grade of Inconel, they usually have very high oxidation resistance at high temperatures. However, it can’t be used at temperatures above 1800 degrees Fahrenheit.

Fasteners you can use for even higher temperatures

In some settings, you will find that you have to expose the fasteners to much higher temperatures, in the range of around 2,000 or even 3,000 degrees Fahrenheit. In such cases, you could use fasteners made out of molybdenum or other alloys. Titanium socket set screws are particularly effective at this range.
For the highest temperature resistance, you could also consider fasteners made out of ceramics, including alumina and zirconia. These products can resist very high temperatures, but the only downside is that they are not very strong and tend to crack easily. They are therefore ideal for use in environments where they are unlikely to be exposed to shock or other similar forces.

About the Author

Larry Melone
By Larry Melone
President

Started my career in the fastener world in 1969 at, Parker Kalon Corp. a NJ based screw manufacturer located in Clifton, NJ working in inventory control, scheduling secondary production and concluding there in purchasing. In 1971 I accepted a sales position at Star Stainless Screw Co., Totowa, NJ working in inside sales and later as an outside salesman, having a successful career at Star I had the desire with a friend to start our own fastener distribution company in 1980 named: Divspec, Kenilworth, NJ. This was a successful adventure but ended in 1985 with me starting Melfast in August 1985 and have stayed competitive and successful to date. Melfast serves the OEM market with approximately 400 accounts nationally.

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