Fastener Materials

Fasteners come in a variety of materials. The choice of materials will be decided by the application and environment. The most popular material options are steel and stainless steel. Other options include alloys based on aluminum, copper, titanium, nickel, cobalt and plastics. Important parameters that will help choose the right material are spelled out in the table below.

Parameters	Application examples
Mechanical (strength, ductility, toughness, fatigue)	Steel fasteners come in several grades – make sure that all static and dynamic loads are identified when choosing the right strength.
Corrosion resistance (galvanic corrosion and stress corrosion cracking)	Several stainless steels and other nickel, cobalt and titanium based alloys have very good corrosion resistance properties. Beware of galvanic corrosion when designing with different metals!
Temperature resistance (high temperature oxidation and creep)	Nickel based alloys are used where high corrosion and heat resistance is needed. e.g., aircraft and land-based gas turbine engines.
Magnetic permeability	Some stainless steels can be obtained with a very low magnetic permeability which is required in applications like magnetic resonance imaging (MRI) scanners.
Weight saving	Some titanium grades show a 40% weight saving compared to steel with equal strength. e.g., automotive applications.