Aerospace Fasteners and its Types

Aircraft fasteners and commercial grade fasteners are both used in high-performance machinery, however it is important they not be confused. For instance, aircraft bolts are made from corrosion resistant steel and can exceed a tensile strength of 125,000 psi. On the other hand, commercial grade fasteners are made from carbon steel, have very little corrosion protection, and their strength is about half of aircraft bolts - between 50,000 and 60,000 psi.
 
There are four main types of fasteners used in aircraft: bolts, nuts, washers, and fastener covers. Bolts are used in areas where extra strength is needed. Aircraft standard bolts are made with alloy steel, stainless/corrosion resistant steel, aluminum alloys, or titanium. These materials allow the bolt to be stronger and lighter than a commercial grade bolt. Aircraft nuts are distinct in two ways. First, they are made from the same material as bolts. Second, they require a locking device to stay in place because of the vibration and pressure they must withstand during flight. These locking devices may be referred to as castle nuts, lock washers, safety wire, and fibre inserts.
 
A washer's function in aerospace is the same as in everyday life - to support fastening systems by distributing the load they bear. However, aerospace washers are constructed of stronger, more lightweight materials. Fastener covers, as their name suggests, are used to provide a cover for nuts, bolts, and washers alike. They are machined in a variety of specialty materials and must be resistant to the fickle environmental factors within the atmosphere. Cadmium, zinc, nickel, silver, phosphate, and black oxide are just some of the materials aerospace fastener covers are made from.