Alloy 718 – What Is It? Alloy 718 To AMS5662

UNS N07718 (Alloy 718) is often seen as the workhorse of the nickel-chromium alloy range, with many applications in Aerospace, General Engineering and the Oil & Gas industry. The grade is one of a type that is precipitation-hardenable, and which, with its addition of niobium, molybdenum, aluminium and titanium, provides a metal that is relatively high strength, and has excellent creep-stress rupture strength and good corrosion resistance. It is easy to weld and durable at high temperatures, although has a spread of operating temperatures of between -200°C and +550°C.

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Alloy 718 is well suited for use in fasteners, pump and valves, turbine parts, motor components, springs, cryogenic tanks, and down-hole applications and tools.

However, as with most grades, there are different variations rather than just one “Alloy 718”.

This article is one of a series that will explain each variant and pin-point differences:

This first article detailed the “Oil & Gas” API 6A CRA properties. This second article will concentrate on AMS5662. A third will address AMS5663 properties, and finally the fourth will discuss the general engineering ASTM B637 standard requirements.

I will compare and contrast API 6A 718 and AMS 5662 below. However, be aware that many end users of Alloy 718 may write their own specifications, usually extending certain requirements of the standards detailed below, and such specifications must always be checked to ensure material conforms with the requirements.

Our AMS5662 stock range stretches between 38 mm to 177 mm in diameter.

Alloy 718 To AMS5662

For bars, forgings, flash welded rings and stock for the same. Typically used for parts requiring high resistance to creep and stress rupture up to 704o C and oxidation resistance up to 902o C. Parts are typically formed or machined, then precipitation heat treated to develop their required properties. AMS5662 material therefore comes with “capability” test results, where the test piece has been aged at the required times and temperatures, then tested to show what results would be achieved with that ageing treatment.

The next paper in the series will consider AMS5663 properties.

Please contact Broder Metals Group Limited, either through the webform section of the website or by any of the other contact methods list on the website if you have any questions.

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Alloy 718 – What Is It? Alloy 718 To AMS5662