There are many factors to consider in machining parts for aerospace applications, such as part shape, weight and durability. These factors will affect the flight safety and economy of the aircraft. The material of choice for aerospace manufacturing has always been aluminum as the main gold. In modern jets, however, it accounts for only 20 percent of the total structure.
Due to the increasing demand for light aircraft, the use of composite materials such as carbon-reinforced polymers and honeycomb materials is increasing in the modern aerospace industry. Aerospace manufacturing companies are beginning to research an alternative to aluminum alloys—aviation-grade stainless steel. The proportion of this stainless steel in new aircraft components is rising. Let’s analyze the uses and differences between aluminum alloys and stainless steels in modern aircraft.
Application of aluminum alloy parts in aerospace field
Aluminum is a relatively very light metal material, weighing about 2.7 g/cm3 (grams per cubic centimeter). Although aluminum is lighter and less expensive than stainless steel, aluminum is not as strong and corrosion resistant as stainless steel, and is not as strong and corrosion resistant as stainless steel. Stainless steel is superior to aluminum in terms of strength.
Although the use of aluminum alloys has declined in many aspects of aerospace production, aluminum alloys still occupy an important place in modern aircraft manufacturing, and for many specific applications, aluminum is still a strong, lightweight material. Due to its high ductility and ease of machining, aluminum is much less expensive than many composite materials or titanium. It can also further enhance its metallic properties by alloying it with other metals such as copper, magnesium, manganese and zinc or by cold or heat treatment.
Aluminum alloys widely used in the manufacture of aerospace parts include:
1. Aluminum alloy 7075 (aluminum/zinc)
2. Aluminum alloy 7475-02 (aluminum/zinc/magnesium/silicon/chromium)
3. Aluminum alloy 6061 (aluminum/magnesium/silicon)
7075, a combination of aluminum and zinc, is one of the most commonly used alloys in aerospace applications, offering excellent mechanical properties, ductility, strength and fatigue resistance.
7475-02 is a combination of aluminum, zinc, silicon and chromium, while 6061 contains aluminum, magnesium and silicon. Which alloy is required depends entirely on the intended application of the terminal. Although many aluminum alloy parts on the aircraft are decorative, in terms of light weight and rigidity, aluminum alloy is the best choice.
A common aluminum alloy used in the aerospace industry is aluminum scandium. Adding scandium to aluminum increases the metal's strength and heat resistance. Using aluminum scandium also improves fuel efficiency. Since it is an alternative to denser materials such as steel and titanium, replacing these materials with lighter aluminum scandium can save weight, thereby improving fuel efficiency and the strength of the airframe's rigidity.
Application of stainless steel parts in aerospace
In the aerospace industry, the use of stainless steel is surprising when compared to aluminum. Because of the heavier weight of stainless steel, its use in aerospace applications has increased more than ever.
Stainless steel refers to a family of iron-based alloys containing at least 11% chromium, a compound that prevents iron from corroding and provides heat resistance. Different types of stainless steel include elements nitrogen, aluminum, silicon, sulfur, titanium, nickel, copper, selenium, niobium and molybdenum. There are many kinds of stainless steel, there are more than 150 stainless steel grades, and the commonly used stainless steel only accounts for about one tenth of the total number of stainless steel. Stainless steel can be made into sheet, plate, bar, wire and tube, making it suitable for a variety of applications.
There are five main groups of stainless steels classified primarily by their crystal structure. These stainless steels are:
1. Austenitic stainless steel
2. Ferritic stainless steel
3. Martensitic stainless steel
4. Duplex stainless steel
5. Precipitation hardened stainless steel
As mentioned above, stainless steel is an alloy composed of a combination of steel and chromium. The strength of stainless steel is directly related to the chromium content in the alloy. The higher the chromium content, the higher the strength of the steel. Stainless steel's high resistance to corrosion and high temperatures makes it suitable for a range of aerospace components, including actuators, fasteners and landing gear components.
Benefits of using stainless steel for aerospace parts:
While stronger than aluminum, stainless steel is generally much heavier. But compared to aluminum, stainless steel parts have two important advantages:
1. Stainless steel has high corrosion resistance.
2. Stainless steel is stronger and more wear-resistant.
The shear modulus and melting point of stainless steel are also more difficult to process than aluminum alloys.
These properties are critical to many aerospace parts, and stainless steel parts occupy an indispensable position in aerospace applications. The advantages of stainless steel also include excellent heat and fire resistance, bright, beautiful appearance. Appearance and excellent hygienic quality. Stainless steel is also easy to manufacture. When aircraft components need to be welded, machined or cut to precise specifications, the excellent performance of stainless steel materials is particularly prominent. Certain stainless steel alloys have extremely high impact resistance, which also affects the safety of large aircraft. and durability are important factors.
Over time, the aerospace industry has become more diverse, and modern aerospace vehicles are more likely to be built with stainless steel bodies or airframes. Despite being more expensive, they are also much stronger than aluminum, and with different grades of stainless steel depending on the scene, the use of stainless steel can still provide an excellent strength-to-weight ratio.
Post time: Mar-02-2023