Engaging in conversations about the materials that define modern aviation, engineers talk about the latest titanium alloys and exotic composites, but none mention AMS 5643. This specification deserves a special mention.
What is AMS 5643?
AMS 5643 is a grade of precipitation-hardened stainless steel (17-4 PH). The specification comes from the Aerospace Material Specification that is managed by SAE International. This is the industry’s materials “bible.” This specification, however, requests a steel that has about 17% chromium and 4% nickel along with small amounts of copper that lets the alloy take on unique attributes when heat treated.
What also makes this material unique is it’s able to merge dichotomous traits— the strength of hard alloys and the resistance of stainless steel.
Why Aerospace Engineers Keep Coming Back
In the aerospace industry, all ‘promises’ must be backed by ‘performance’ to sustain a place. AMS 5643 has credibility and proven worth. AMS 5643 is used in different locations of the plane, in the structure, the landing gear, and the fastening systems.
One of the reasons the material is so flexible is its ability to be machined while in a soft state and later undergo a heat treatment to become hardened. It achieves an impressive strength of about 1,000 MPa or greater. This allows the manufacturer to create complex geometries that would be impossible to create using an extremely hardened material. They can also enhance the strength of the component afterwards.
Apart from being able to withstand various conditions, the material should also be able to withstand corrosion. 17-4 PH should also be able to endure aircraft environmental conditions, including de-ice chemicals during winter, and salt-laden air during coastal runways. It should be able to endure corrosion while also being in a harsh environment without depleting the alloy.
Practical Considerations
However, every material has its drawbacks and therefore should be used in a specific manner and conditions. AMS 5643 should be exposed to conditions where moderate limitations are required. In applications where the temperatures are extremely high or lower, special attention should be provided to the design.
The martensitic structure of the material also gives it certain magnetic properties. This may be beneficial in some applications as it may be required, however, in Some systems it may be a disadvantage if nonmagnetic materials are required.
Looking Forward
As technology grows, so does the relevance of AMS 5643. Even though newer alloys and composites are grabbing peoples’ attention, this specification continues to be of value since it offers a great balance of the diverse properties considered at a total cost that is hard to beat, and this is an engineering aspect that never gets old.
In aerospace design and manufacturing, the understanding of AMS 5643 and what it offers is part of the fundamental knowledge to be held. This is the result of many years of development in the different areas of metal’s value and a proof that in many situations, the reliable answer to a problem is of great simplicity and is the most used.