Types and Materials of Aerospace Fasteners
Due to the demands and stresses they operate under, fasteners used in the aerospace industry must be manufactured under incredibly strict high-quality and high-precision design and manufacturing standards. The aerospace industry uses a wide variety of fasteners, such as screws, rivets, nuts, bolts, pins, and collars.
As aerospace equipment is exposed to extreme environments, such as high pressures and temperatures from leaving the earth’s atmosphere and exposure to burning rocket fuel, they must be designed and constructed to endure these conditions, even down to the fasteners that hold them together. As a result, several different designs of high-quality fasteners have been developed which are suitable for the specifications and standards of the aerospace industry, each of which exhibits different characteristics and qualities.
- Aerospace fasteners must possess:
- High corrosion and oxidation resistance
- High tensile, shear, and fatigue strength
- Lightweight construction to optimize lift in planes and minimize fuel costs in rockets
- Operational capabilities in extreme environments like low and high temperatures and pressures.
- Self-sealing and self-locking capabilities to prevent fluid and pressure leaks and loosening during operations.
Aerospace fasteners are typically made from aluminum, steel, titanium, and superalloys. Aluminum is most often used in atmospheric aircraft, and can be used in aerospace applications as well, provided it receives the proper surface treatments. Although aluminum rivets are common, achieving aerospace standards requires that it be cold head formed. Even then, the material is sensitive to temperatures above 250 degrees Fahrenheit, as well as stress-induced corrosion.
Steel and its various alloys feature high strength and surface hardness. However, steel is also heavier than other materials, which can create issues when designing aircraft and spacecraft. Stainless steel and steel alloys are the main types of steel used in aerospace, but certain types are susceptible to heart damage and failure. Therefore, choosing the right type for the job is critical.
- Series C300 corrosion resistant (CRES) stainless steel is not as heat resistant as others, and is primarily used for aircraft screws, bolts, and some fastener covers.
- CRES series 400 is more heat resistant, but more vulnerable to corrosion.
- Precipitation-hardened PH stainless steel of various grades is used for some fastener applications.
- Alloy steels are durable, but vulnerable to corrosion.
There are surface treatments to prepare steel for aerospace applications, but these can also decrease the metal’s carburization and resistance to tension corrosion.Titanium can serve as an alternative to aluminum, as it is as strong as steel, relatively light, and can operate at -350 to 800 degrees Fahrenheit.
Superalloys are commonly used as fasteners due to their ability to withstand many different types of stresses. They are versatile, able to maintain structural and surface integrity in extreme environments and are resistant to creep factors. Commonly used superalloys include:
- A286: an iron-nickel-chromium alloy that can withstand temperatures between -420- and 1200 degrees Fahrenheit, and is often used in engines, superchargers, and turbines.
- H-11: a 5% chromium steel alloy with high impact resistance and hardness, making it useful for landing gear assemblies.
- Hastelloy: a nickel-molybdenum-chromium superalloy with high corrosion resistance, used in combustion and exhaust components.
- Inconel-718: Nickel-based superalloy, retains a 220ks (kilopound per square inch) tensile strength up to 900 degrees Fahrenheit.
At Parts Needed Yesterday, owned and operated by ASAP Semiconductor, we can help you find all the fasteners for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the aviation parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at email@example.com or call us at 1-434-321-4470.