Aerospace Fasteners: Features and Types
Aerospace is one of the most sensitive industries where even a minor screw plays a vital role in keeping the aircraft in the air. The performance of aircraft is also dependent on the fasteners.
If you are interested in learning more about aerospace fasteners, the guide below can help you. So, let's read.
What are Aerospace Fasteners?
Aerospace fasteners attach the aircraft components together and play a crucial role when it comes to the safety of travelers. The aerospace industry covers a lot of aircraft, which are composed of commercial, military, and spacecraft, each having significant importance.
Aerospace fasteners hold all the aircraft components together and are different from general types of fasteners.
Features of Aircraft Fasteners
Aircraft fasteners have different qualities that make them suitable for aerospace applications, and some of these are as follows:
High Strength
Aircraft are subjected to high pressure and stress when flying. Therefore, they need to have high shear and tensile strength to withstand loads. Turbulence is also highly common in the aerospace sector, and this strength plays a vital role.
Thermal Resistance
Thermal resistance in airplanes is crucial, as thermal failure is common due to exposure to high temperatures. The fasteners' being thermally resistant helps maintain their performance.
Lightweight
Aircraft have multiple fasteners, and the weight of each fastener should be low so that the aircraft's weight is also low. If the fasteners are heavy, the aircraft's performance can be compromised.
Corrosion Resistance
Aircraft are subjected to moist environments and require corrosion-resistant fasteners.
Aviation Quality Standards
The aviation quality standards for aerospace fasteners are as follows:
SAE AS9100 is the standard that is international. It works with the production, development, and installation of aircraft components, which also include fasteners.
ISO/TC 20/SC 4 is an ISO committee that is associated with aerospace fasteners. It has standards that have a very detailed insight into the material and design of fasteners.
Types of General Purpose Aerospace Fasteners
There are four types of general-purpose aerospace fasteners, which are discussed below:
1. Aircraft Bolts
The aircraft bolts are threaded fasteners that have threads on the external part and these are used for creating temporary joints.
They can offer seamless fastening capability and even can resist dynamic loads. They are made using aluminum or steel alloys and have a coating that helps with corrosion resistance.
2. Aircraft Nuts
Aircraft nuts are mating parts for screws and bolts which have internal threads. They have excellent material properties and are compatible with the mating parts.
3. Aircraft Screws
Screws are aerospace fasteners that are very commonly used. They have external threads with a high helix. There are different types of aircraft screws that have different types of designs, screw heads, and materials.
4. Aircraft Rivets
Aircraft rivets are structures that have pins and have a deformed end on one side. They help to join metal sheets in the aircraft body and offer a very strong grip.
Special Fasteners Used on Aircraft
Aircraft also have some special types of fasteners that are used for special purposes, and these are as follows:
1. Hi-Tigue
Hi-tigue fasteners have bead encircles on the bottom part, which improves the strength of the joint.
During installation, it is pressed against the wall of holes, creating stress around the area, which causes the joint to strengthen. There are two types of collars in hi-tigue fasteners: sealing and unsealing.
2. Taper-Lock
Taper-lock is the mostly used special fastener in the building process of airplanes. It has a tapered design that fills the hole without any deformity on the shank.
The washer head nut pushes the metal against it, which has tapered walls. It creates a compression and a strengthened connection.
3. Turnlock Fasteners
The turn lock fasteners are meant to secure doors, removable panels, and plates on the airplane. It can offer immediate openings. During inspection, the panels can easily be removed.
4. Dzus Fasteners
Dzus fasteners are composed of a spring, stud, grommet, and receptacle. It consists of an aluminum alloy, which makes the grommet. It also comes with a spring, which is made using cadmium-coated steel, which keeps it away from corrosion.
The studs, on the other hand, are made of cadmium coating and steel. They have three types of heads: oval, wing, and flush.
Available Materials for Aerospace Fasteners
Aerospace fasteners are manufactured using different types of materials, which are as follows:
Aluminum
Aluminum is very commonly used in aerospace applications due to the strength it offers and being lightweight. It is also highly corrosion resistant and once they are coated, they become excellent to use in aerospace.
The T6-A170xx series of aluminum is known as space-grade aluminum and is used for aircraft bodies.
Steel
Aerospace fasteners are also manufactured using steel as they offer durability to the joints. Steel is heavy compared to aluminum. Steel is also treated to offer corrosion and heat resistance.
Titanium
Titanium is a strong material and light. It offers high resistance against corrosion and thermal stability. It is one of the most suitable options but is a bit expensive.
Super Alloys
The aerospace industry also uses some special alloys for fasteners, which are opted for their durability, less weight, enhanced thermal stability, etc. Some of these superalloys that help manufacture aerospace fasteners are chromium, nickel, Hastelloy, Inconel, etc.
Aerospace Fasteners vs Commercial Grade Fasteners
Aerospace fasteners and commercial-grade fasteners look alike, but aerospace fasteners are highly superior in performance. A commercial-grade fastener is never a suitable choice for aerospace applications.
Aerospace fasteners are made using high-quality steel, whereas commercial-grade fasteners are made using carbon steel. Also, the strength of aerospace fasteners is higher than that of commercial ones because aerospace fasteners are heat-treated.
The fasteners in aircraft have improved material properties, which make them prone to vibrations and offer corrosion and heat resistance.
Similarly, the aircraft passes through vibrations; hence, they have self-locking mechanisms, which commercial-grade fasteners do not. However, the cost of aerospace fasteners is high.
Conclusion
If you are inclined to have aerospace fasteners manufactured for your aerospace applications, you can contact us at DEK. We have experience and expertise with our well-skilled engineers who offer to design custom aerospace fasteners.
FAQs
What materials are fastener covers made of？
Fasteners' covers are made from materials like cadmium, nickel, and zinc, which makes them suitable for extreme operating environments.
Why use blind fasteners in aircraft?
The blind fasteners in an aircraft help to couple the components in airplanes together and reach the inaccessible spaces of an aircraft.
What are the optional surface finishes for aircraft fasteners？
The surface finishing options for aircraft fasteners are polishing, anodizing, and painting.
What hole fit tolerances are appropriate for aerospace fasteners?
There are different factors on which the hole fit tolerance depends, such as the material opted for fasteners, the working conditions, the type of fastener, and surface finishing.
