How to Select a Fastener’s Material?

It is hard to imagine a modernized world without fasteners. These small, often unnoticed, components help bind every building, machine, and vehicle we see. Choosing the right fastener for your project is crucial and will vary based on the application. While there are several factors that one should keep in mind when dealing with fastener selection, this blog will focus on choosing the right material for the job.

Using the right material for a fastener is as important as its size specifications. For example, just as a 0.50mm bolt would not fit into a .70mm hole, a steel rivet would not be compatible with an application that requires titanium. Most industrial fasteners are made from aluminum, brass, steel, synthetic nonmetals, and exotic materials. Materials are commonly evaluated against rigorous criteria such as strength, corrosion resistance, temperature resistance, and shear or tensile stability. Once appraised, one should consider the demands of their project and see which material best suits the application.

Steel

Steel accounts for the vast majority of fasteners produced annually. Since the industrial revolution, it has been a staple among engineers to hold structures together. Steel is reliable, has incredible tensile strength, and is comparatively cheaper to manufacture than other materials. Additionally, steel is naturally resistant to corrosion and can withstand pressures of up to 300ksi.

Stainless Steel

Stainless steel, an alloy made from low carbon steel and chromium, offers magnified corrosion resistance. As such, it is a very popular material for the aerospace industry. However, there are several different types within the category of stainless steel fasteners, some of which are more susceptible to heat damage. Therefore, if one chooses stainless steel for an aerospace application, it is crucial to understand the individual fastener's heat resistance profile.

Aluminum

Aluminum is a favorable material for fasteners due to its relatively low cost and light weight. In addition, it is inherently resistant to corrosion and can readily be mixed with other metals to make a number of alloys.

Titanium

Titanium is an excellent choice for applications needing extreme temperature resistance, high tensile strength, and galvanic corrosion resistance. As such, its use is widespread in naval, aviation, and space vehicles. However, titanium is more expensive than other options.

Ceramics

Ceramic may seem like a peculiar choice of material for fasteners, but it works very well for certain applications. Ceramics can survive in extremely high-temperature environments and are essentially immune to the effects of corrosion. Unfortunately, they are highly susceptible to torque and can break rather easily if too much is applied. Therefore, their use is limited to applications in which there are dramatic temperature fluctuations.

If there is any confusion about what material should be used for a specific application, one should always follow the manufacturer's recommendation or consult an expert. Selecting a material not suited for its operating environment can lead to equipment failure and other hazards. Additionally, some may be tempted to replace older fasteners with a "stronger" material, but it is usually recommended to stick with the same material.

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