What are high-temperature fasteners and how do you choose the correct one for your application?

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High-temperature fasteners are used extensively in critical industries such as semiconductor, aerospace, automotive, and oil/gas. They are specially designed to be able to withstand high temperatures and extreme environments. On top of that they are designed to withstand the alternate phases of extreme heat and cooling without damaging the fastener. Fasteners created from alloys that are not designed for high-temperature environments will oxidize (corrode or rust) if used in these environments. The fasteners will also expand as the temperature rises, putting pressure on the hole it was driven into, then contract as the temperatures go back down, which makes them loose inside of the hole.

What alloys are typically used to create high-temperature fasteners?

There is a wide range of materials that have been created over the years to perform within challenging high-temperature environments. The table below lists the most common.

MaterialMax. TemperatureDesirable Qualities
A-268 / Alloy 660Up to 1300°FAlloy of iron, nickel, and chrome which gives higher strength and exceptional oxidation resistance
Alloy 330Up to 2100°FOne of very few materials that can handle extreme temperature changes, plus alternate carburizing and oxidizing atmospheres
Ceramics (Alumina, Zirconia)Up to 4000°FExtremely temperature and corrosion resistant – however brittle
Engineered Polymers (PTFE, PEEK, PAI)Up to 572°FExceptional mechanical and physical properties with chemical and corrosion resistance, stiffness, high tensile strength, impact resistance, with some heat resistance
Nickel Alloys (Inconel 600, 625, 718)Between 1300°F – 2000°FGood oxidation, corrosion, and carburization resistance, maintain strength in corrosive environments
Stainless Steel 309, 310Up to 2250°FHigh content of chromium and nickel which give additional corrosion resistance
Stainless Steel 630Up to 1100°FExceptional hardness, great strength, good ductility
WaspaloyUp to 1600°FExtreme temperature and oxidation resistance in combination with high strength

How do you select the right high-temperature fastener for your application?

The correct fastener materials for any application are selected based on their mechanical properties, potential for post-fabrication treatments, cost-efficiency, and other considerations. However, which material would be best for your application truly depends on what you need the fastener to join and where.

In order to select the right fastener for your high-temperature application you need to know:

  • Exactly how hot the environment will be (on average)
  • How long the fastener will remain at extreme temperatures
  • If the fastener will be exposed to other corrosive forces
  • If the fastener will be exposed to vibration, shock, or other physical forces

As the table above shows, plastics really have no place in environments with extremely hot temperatures only able to withstand up to 572°F, A-268 can withstand temperatures up to 1300°F, while certain Nickel alloys can withstand temperatures up to 2000°F. If your application requires fasteners to perform in extremely high temperatures you will need to consider ceramic options. Keep in mind that there is a trade-off with ceramics. Yes, they can withstand extremely high temperatures and corrosive environments but they may crack or break if jostled, as they do not have the strength characteristics that metal alloys provide. You really need to take a close look at the average temperatures that the fastener will be required to operate in to be sure that the material can handle it.

How can UC Components, Inc. help you?

While the right materials, coating, plating, or finishing treatment for your fastener application is best defined by your process engineer, we are always here to assist you.

We offer a variety of standard and vented hex nuts, washers, and screws, numerous finish options, along with specialized venting designs, complete custom product development, and Class 100/ISO Class 5 Cleanroom cleaning & packaging. If you do not see the fastener or material that you need listed in our standard products, please give us a call! We may not stock it but we are happy to acquire and manufacture just about any fastener you need.

UC Components, Inc. has been the world leader in high vacuum hardware since 1974. We specialize in fasteners for High Vacuum, Ultra High Vacuum, and other critical applications. View our parts catalog online to find the components you need, request a quote, or contact us for more assistance or additional information.

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