(supersedes all previous editions)
Inconel 718 is a high strength nickel base superalloy used for cryogenic temperatures up to long term service at 1200°F. The alloy is readily fabricated and may be welded in either the annealed or precipitation (age) hardened condition. Anneal 1700 -1850°F, air cool or faster. Age 1325°F 8 hours, furnace cool to hold at 1150°F, for a total aging time of 18 hours, air cool. Alloy 718 will show a contraction of 0.0008 inch/inch after precipitation hardening.
Alloy 718, a nickel based superalloy, developed initially for use in rotating parts in aerospace and gas turbine applications, has become the preferred material for the manufacture of Wellhead Components, Auxiliary and Down Hole Tools, and Sub-Surface Safety Valves.
The alloy also possesses excellent sub zero toughness and resistance to hydrogen embrittlement, both factors which can be as important as strength and corrosion resistance. Normally supplied using a 'double vacuum melt' process - either VIM/VAR (vacuum induction melting, followed by vacuum arc remelting), or VIM/ESR (vacuum induction melting, followed by electro slag refining), though an air melt and double VAR melting practice is also permitted by many material specifications.
Strength levels up to 150 KSI 0.2% PS can be achieved by either careful heat treatment and/or a restricted chemical analysis.
Disclaimer: Recommendations are for guidance only, and the suitability of a material for a specific application can be confirmed only when we know the actual service conditions. Continuous development may necessitate changes in technical data without notice. This datasheet is only valid for Alleima materials.