Aluminum vs Stainless Steel: The Rivalry for the Best Material to be Used in the Aerospace Industry
Most people forget that safety in air travel starts with a solidly built aircraft. Aside from securing the most qualified aircraft pilot or air traffic controllers. An aircraft made from the best quality tools, components, and the highest quality of raw materials is necessary in the aerospace industry.
Therefore, to ensure the airworthiness of the aircraft, it is necessary to evaluate which raw material should be used. For several years, aluminum aircraft alloy has remained the number one material used in the aerospace industry.
According to experts, aluminum was considered the perfect material for creating aerospace tools and components. It is due to its lightweight nature, ease of machinability, and strong corrosion resistance. Readily available, aluminum aircraft alloy was used for creating the fuselage, including the aircraft’s main components.
However, in recent years, stainless steel has made its way into the industry with its high strength, corrosion resistance, and temperature resistance.
Let us examine their similarities, differences, strengths, and weaknesses. This is to help make an informed decision regarding the best raw material to utilize in the aerospace industry.
Aluminum Aircraft Alloy for Aerospace
Ever since the Wright Brothers built the first powered aircraft in 1903, aluminum has been the chosen material. It is perfect for heat-strengthening and appropriate grinding processes to forge it into tools and engine parts. Even during World War II, the use of aluminum flourished to the point that the government required civilians to donate scrap aluminum as part of their war efforts.
Over the years, with advancements in technology, simple machining processes evolved into complex ones. However, aluminum still dominated the aerospace industry. This versatile raw material is sought after for centerless grinding and other metalworking operations to produce fasteners, round bars, rods, and other essential aircraft parts.
Stainless Steel for Aerospace
The aerospace industry, with its continuous focus on durability and safety in aircraft, led to the exploration of other raw materials that might surpass the capabilities of aluminum. This exploration brought stainless steel into the picture in the aerospace industry.
Thanks to Harry Brearley’s accidental discovery in 1913, stainless steel was introduced to the world and proved to be an integral part of our daily lives. It also became essential in the aerospace industry as it rapidly expanded through technological advances.
During the early years of its discovery, only a few types and grades of steel were available. But even then, it was more valuable compared to other metals. And, in the aerospace industry, such as the creation of turbo superchargers and exhaust systems.
Over the years, stainless steel continued to compete with aluminum aircraft alloy, boasting higher resistance to corrosion and usual wear and tear. Despite its added weight compared to aluminum, stainless steel continues to be increasingly utilized in the industry. It is primarily useful in areas where the added weight is tolerable.
Both alloys have become key players in the aerospace industry. However, it is important to highlight their key differences in the following factors:
Ease of Machinability
In general, aluminum has better ease of machinability compared to steel alloys. Its malleability and ability to be pushed to extreme dimensional limits make it suitable for a wide range of applications.
However, when comparing aluminum to steel with regards to ease of machinability, it is important to be specific about which steel alloy is being compared. This is where stainless steel comes into the picture for an accurate comparison.
As a matter of fact, both aluminum aircraft alloy and stainless steel have the same level of ease of machinability. Both materials exhibit good formability, weldability, and are designed for machining, centerless grinding, and other metalworking operations.
Weight
As mentioned earlier in this article, aluminum aircraft alloy has an edge over steel alloys due to its lightweight nature.
According to expert studies, steel is harder than aluminum, making it heavier and denser. The strength and density of steel correlate with the amount of chromium in its mixture. The strength and density of steel make it more resistant to scratches compared to aluminum.
However, the density of steel is the major reason why its widespread use in the aerospace industry is limited to areas where the added weight can be tolerated, such as in centerless grinding and metalworking processes for the creation of tools and components.
Cost
Cost is always an important factor for manufacturers when choosing the raw material to use. In fact, it is often considered the primary factor to consider. The aerospace industry is no exception when it comes to considering cost in the creation of tools and components.
In comparison to aluminum aircraft alloy, steel is a more common and cheaper alternative. The primary reason for aluminum being more costly than steel is its supply and demand. Aluminum is more difficult to find and reproduce and was once as coveted as gold and silver by various industries.
Rust and Corrosion Resistance
Considering that the main aim of choosing the right raw material in the aerospace industry is to ensure the airworthiness of the aircraft, the factor of rust and corrosion resistance is crucial.
Aluminum is highly corrosion resistant, meaning it has a natural resistance to rust and corrosion, unlike steel, which requires further treatment to achieve such resistance. However, it is important to note that stainless steel, with its added chromium content, is at par with aluminum in terms of rust and corrosion resistance. Adding chromium to stainless steel does not significantly affect its cost and it is still cheaper compared to aluminum aircraft alloy.
Who Takes the Medal?
Considering the characteristics and capabilities of both aluminum aircraft alloy and stainless steel, it is up to manufacturers to make the choice of which raw material to use when creating important and marketable aircraft tools and components through centerless grinding processes and other metalworking operations.
However, it is important to note that a monopoly of a single raw material in the industry is not necessary. In fact, it is best to harmonize the use of both materials and have them coexist to create airworthy aircraft. Coexistence is possible by using aluminum in some aircraft parts and utilizing steel in areas where weight is not a problem. Therefore, both raw materials deserve recognition as they prove to be useful in the industry but for different applications.
You may have gained valuable information from this article about steel and aluminum, but your quest shouldn’t end here. If you are from the aerospace industry and are interested in having your aluminum or steel parts fabricated, machined, or undergoing centerless grinding processes, don’t hesitate to contact us and benefit from their efficient services! Whatever metalworking or abrasive centerless grinding process you may need, rest assured that we can meet your set standards. Request a quote today!
