When it comes to purchasing materials for use in aerospace applications, the specifications can seem very daunting to the less experienced eye. However, these specifications are in place for a good reason, as not only do safety guidelines have to be adhered to, but they allow for the distinction between a part that works best at 30,000 feet and one that does not. AMS 5643 is a specification that plays a vital part of making aircraft parts for commercial and/or military aircraft.
What AMS 5643 Actually Is
AMS 5643 is a specification that refers to a grade of precipitation-hardening stainless steel, which is more commonly referred to as 17-4 PH. This grade of steel is published in a document by SAE International, a publication that was formerly referred to as the Society of Automotive Engineers.
This publication defines the specifications for the use of steel bars, forgings, and steel rings in the aerospace industry. The material is a high-strength, corrosion-resistant alloy that contains 17% chromium, 4% nickel, along with smaller amounts of copper and niobium. The reason that this material is so sought-after is that it can be heat-treated to high strength levels, yet it still maintains a reasonable amount of corrosion resistance.
Common Applications in Aviation
If you were to walk into any aircraft maintenance facility, you would find that the material specified by AMS 5643 is used in a variety of places. For example, landing gear components are a major application for this material, since they require a high level of strength, good toughness, and are exposed to corrosive de-icing fluids. Actuator components, hinges, brackets, and a variety of other fittings are also made from this material. The aerospace industry has decades of data on the performance of 17-4 PH, and it is a familiar material that is trusted. In a few cases, manufacturers are using this material for engine mounts and firewall components, since it is strong and will handle moderate temperature excursions up to 300°C for short periods of time.
Although the AMS 5643 has an excellent balance of mechanical properties, there are times that another material would be a better fit for the application. For example, for higher temperature applications, a nickel-base superalloy would be required. For applications where weight is a critical factor, aluminium and titanium would be good alternatives despite the higher cost and processing difficulties. The Custom 450 and 455 stainless steel have the same characteristics and a different mechanical property profile. They would be good alternatives for some applications, although they do not have the same aerospace application history.
Getting Started
If you’re considering the AMS 5643 for a new application, the first thing to do is to obtain a copy of the full specification and read through the requirements that your suppliers must comply with. The best thing to do is to involve your material suppliers early in the design process. They will be able to provide information on the forms and processing that will be required for your application.
The most important thing to do is to involve your quality and certification department in the procurement of the materials. And the good thing about this spec is that its fully compliant with industry standards – and so the only thing required here is whether it meets the needs of your requirements.
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