An aircraft fastener has many essential characteristics to make it a desirable choice. Some of them are high tensile strength, high shear strength, low brittleness, and a modified crest. But, first, we will look at some characteristics and improve the performance of your aircraft fasteners.
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High tensile strength
Several materials are used to construct aircraft fasteners, and alloy steels are preferred materials for aerospace applications from top fastener distributors. They are more lightweight than steel, but they must be treated before use. In addition, some commercial aircraft fasteners are made of titanium, which is light and highly corrosion-resistant. Inconel 780 is another type of aircraft fastener, and it has the comparable tensile strength to steel but is resistant to stress-induced corrosion.
Aerospace fasteners consist of threaded devices such as nuts and bolts. They are made of alloy steel, stainless steel, titanium, or anodized aluminum alloy. Like bolts, aircraft nuts are always used with a corresponding bolt. Nuts are available in non-locking and self-locking varieties. Screws, on the other hand, feature a threaded hole and are composed of lower-strength materials than bolts.
High shear strength
The high shear strength of aircraft fasteners is essential for many reasons, including safety. Most aircraft are assembled with the help of fasteners, such as rivets, screws, and bolts. The joint analysis measures a fastener’s shear and bearing strength. These allowable are commonly available and are based on tests. If a fastener is too weak, it can be replaced by a stronger one.
Aerospace fasteners are often made of high-quality materials. They are highly durable and are used to fasten parts of military aircraft, ballistic missiles, and space-bound rockets. The fasteners used in these aircraft must be strong yet lightweight since the aircraft’s weight will be significantly reduced. Some aerospace fasteners are light, while others have extra security features. They are also crucial for airplane safety and must meet strict standards.
Stainless steel and alloy steel are excellent material choices for aircraft fasteners because they are lightweight and have great heat and cold resistance. Thanks to its high strength-to-weight ratio and corrosion resistance, titanium can replace aluminum in some commercial aircraft fasteners. Hastelloy is another good option because it has excellent corrosion resistance and applications in aircraft exhaust systems. While it is expensive to use, it is considered a superior material for aerospace fasteners.
As aircraft fasteners are CNC-machined aerospace parts, they are widely used to produce the aerostructure. Aerospace fasteners are indispensable for joining the intricate parts of an aircraft. The aerospace industry is very particular about weight and safety, so its products must meet stringent requirements. The low brittleness of aircraft fasteners is an essential factor for aircraft safety and efficiency. Therefore, it is necessary to look for the highest quality aerospace fasteners available.
Modified crest to minimize stress concentration
The J-form thread profile is widely used in aircraft fasteners. The extensive root radius and modified crest reduce stress concentration and ensure that a screw can be driven into a hole in an aircraft fastener without damaging it. Generally, the crest and root radius are equal, but aircraft fasteners often have a longer length. Therefore, an aircraft fastener should have a radius equal to or larger than the critical part dimensions to ensure a proper fit.
When bolts are tightened in an aircraft fastener, they need to be only as tight as is required to prevent the threads from losing under vibration or anticipated bending forces. Unfortunately, metric aircraft fasteners are not widely available in the U.S., so manufacturers must order them from a supplier specializing in aircraft fasteners. Fortunately, ARP offers ISO fasteners in bulk, with long threads and a small grip increment.
J-form thread profile
Some fasteners on airplanes have J-form threads. These threads have a radial root radius of about 1/16 inch and are intended for high-temperature, high-stress, and high-fatigue applications. “J” series threads are designed for use in aircraft engines, space vehicles, and missiles. These threads are difficult for metal cutting operations.
The UNJ thread profile is used to ensure maximum fatigue strength for safety-critical aircraft components to ensure the sturdiness of aircraft fasteners. It features a controlled root radius on the external thread, more significant than the standard UNR thread, and an increased minor diameter to accommodate the larger external root radius. In addition, the pitch diameter of UNJ threads is controlled within close tolerances.
Read also: What Is Aerospace Anodizing