What is AMS5666?

AMS5666 is a specification covering the supply of an alloy similar in composition to Inconel 625 for aerospace applications. It covers multiple different product forms including forgings, extrusions and rings, although we are most interested in the stocking and distribution of solid bars.

AMS stands for ‘Aerospace Material Specifications’ and AMS5666 is one of thousands of documents covering the production of materials and products for use in aerospace applications. The AMS standards are issued and maintained by the SAE authority. Formerly named the Society of Automotive Engineers, this USA-based association has a focus on global transport industries, such as aerospace, automotive and commercial vehicles.

The difference between the composition defined by AMS5666, and another products standard such as API 6A, ASTM B446 and NACE MR0175 / ISO 15156-3 is relatively small. Therefore, it is possible that a single product can be produced to meet all these various specifications, be they for aerospace, Oil & Gas or the chemical processing industries. Langley Alloys stock will meet this AMS5666 specification and can therefore be supplied for aerospace use, even though many our customers are focused on other applications.

Inconel 625 is a nickel-based alloy, also known in the Unified Numbering System (UNS) as N06625, Alloy 625 or DIN 2.4856.  Inconel 625 was launched in 1964 following development by Special Metals Corporation and found early use in power station components due to its resistance to high temperature oxidation.  Inconel 625 achieves reasonably high strength through the addition of molybdenum and niobium to the nickel-chromium base, but nowhere as high as Inconel 718. However, due to the high level of chromium and molybdenum it is highly corrosion resistant in the most aggressive of environments.

Alloy 625 is certainly one of the more expensive alloys we stock, given its high nickel content (>58%). However, it provides strong performance at temperatures more than 800degC.   nb. Special Metals suggest service temperatures from cryogenic up to 980degC for their Inconel 625 product, although mechanical properties do start to drop off more significantly from 650-700degC.

The high nickel content of Inconel 625 ensures that it forms a protective oxide layer when exposed to elevated temperatures, thereby preventing any further oxidation. Given this ability to tolerate high temperatures, Inconel 625 is an obvious candidate for aerospace applications. Engine components towards the exhaust-side are commonly machined from Alloy 625, such as nozzles, seals, heat shields, valves and fasteners.

Langley Alloys current stockholding goes from ½” (12.7mm) to 10” (254mm) diameter solid bars. We are also able to offer in-house inspection, testing and CNC machining (such as deep hole boring) to simplify your supply chain.

Inconel is a registered trademark of Special Metals Corporation.

Got any Questions? Get in Touch

For more information about nickel-based alloys, please don’t hesitate to contact us today. We would be happy to answer any questions that you may have regarding specifications and common applications.

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