Modern aircraft are amazing feats of technology and engineering. They are built to be durable, safe, and as efficient as possible, and so they rely on the most advanced materials available on the market today. That’s why it should come as no surprise that all types of airplanes contain a variety of stainless steel alloys.
The first metal an average person might think of when they see an airplane is aluminum, but in recent years, premium, high-performance stainless steel is figuring more and more prominently in their design. Because it is strong, durable, and affordable, stainless steel fulfills many functions on modern aircraft to ensure they continue running at the highest level throughout their lifetime.
Some of the roles played by stainless steel may surprise you, so today we’re examining the various uses for this incredible metal to ensure today’s air travel is safer and more reliable than ever before.
What advantages does stainless steel offer for aircraft?
The popularity of stainless steel in the aerospace industry is not difficult to explain. Obviously, when you’re dealing with flying vehicles that must be able to carry hundreds of people at high altitudes over long distances, it’s critical that every material you use is extremely reliable. Stainless steel has a well-earned reputation as a metal that is not only dependable but also easy to work with.
Stainless steel is probably most recognized for its excellent corrosion resistance. Every grade is able to withstand atmospheric and pure water environments with remarkably low levels of corrosion, while the higher performance grades can also resist corrosion in acid and alkaline solutions and marine environments. Airplanes travel the world and so are exposed to all sorts of conditions, not to mention spending much of their time at high altitudes. The more resistant to corrosion they are, the better.
Of course, steel is also one of the strongest metals, and stainless steel is no exception. Austenitic alloys are able to be work-hardened, enabling significant strengthening options. Especially with certain high-strength duplex grades, stainless steel also offers a high strength-to-weight ration, an important consideration in aircraft.
Other advantages of stainless steel include its superb heat and fire resistance, bright, aesthetic appearance, and excellent hygiene qualities. Stainless steel is also easily fabricated, an important consideration with all the various shaped parts of an aircraft that must be welded, machined, or cut to precise specifications. Finally, certain stainless steel alloys offer extreme impact resistance, an important factor when it comes to the safety and durability of large aircraft.
How is stainless steel used in modern aircraft?
Because of its extreme versatility, stainless steel can be used for virtually any metallic part found on an aircraft. However, practical considerations such as cost and weight mean that aluminum is often (but not always) the first choice for many airline parts. Yet we are seeing that airplane manufacturers are increasingly relying on stainless steel for certain parts that have higher performance requirements.
For example, the fuel tanks on many airplanes are made from stainless steel. This makes sense, as not only are fuel tanks exposed to extremely corrosive materials, but also must be able to withstand high temperatures and protect from structural damage. This same principle extends to exhaust components, engine parts, and other crucial systems related to the airplane’s power source.
Other parts that will likely be made from stainless steel are key structural components, such as fasteners. These are what hold together the airplane, and can be found in the landing gear, the wings, the engines, and the cockpit. In engineering, the fasteners are often the weakest link of any structure, and particularly in an airplane, you can’t afford anything less than the most reliable options available.
Of course, not every aircraft is an airplane. The aerospace industry is becoming more diversified over time, and includes the latest rocket ships being designed by new private companies trying to make space travel more accessible and affordable. Modern aerospace vehicles are much more likely to be built with stainless steel airframes or fuselages. While more expensive, they are also much stronger than aluminum, and depending on the grade used, can still offer an excellent strength-to-weight ratio.
Which alloys are most commonly found in aircraft?
You can find a number of different stainless steel grades and alloys in modern aircraft. This starts with what is likely the most popular stainless steel, 304. This austenitic stainless steel is known to be weldable, formable, and machinable with good corrosion resistance. Applications you are likely to find it in include aircraft tubing, wiring, sheet metal, and more.
Another high performance alloy found in aircraft is 321. Because it is alloyed with titanium, this grade is especially resistant to intergranular corrosion. This alloy can withstand temperatures in the 800 to 1500°F range and still maintain its stability. Common uses in the aircraft industry include jet engines, exhaust ducts, flanges, piston engine exhaust manifolds, afterburners, flash boilers, and more.
Also popular is alloy 316. This particular grade is especially renowned for its corrosion resistance in marine environments. Besides austenitic steels, 430 is corrosion and heat resistant, and ideal for decorative trim. 410, a martensitic alloy, is popular for parts that must withstand high stress with good corrosion resistance and strength. Precipitation hardening stainless steels such as 13-8, 15-5, 17-4, and 17-7 have levels of corrosion resistance comparable to austenitic varieties, but after undergoing precipitation hardening can achieve even higher strengths than many martensitic grades. These are especially attractive when high performance metals are necessary
Your Technical Services Provider
When you’re working in an industry in which safety and performance are critical, such as the airline industry, ensuring you have the right material is of primary importance. At Clinton Aluminum, our team of seasoned professionals has dedicated their careers to helping our clients succeed. We know how important it is to get it right the first time. That’s why we’re committed to working with our customers through every step of the production process.
Clinton Aluminum is the Midwest’s leading aluminum and stainless steel supplier. That means we have the experience and expertise that our customers have come to rely on. If you have any questions, please don’t hesitate to contact us today.
