Alloy 718 (UNS N07718, 2.4668) is a high-strength, corrosion-resistant nickel chromium alloy. The additions of Nb, Ti and Al form a series of precipitates with Ni during the controlled solution annealing and ageing process steps, resulting in a significant increase in strength and hardness of this alloy compared with alternative nickel alloys. It can be supplied in a variety of different strength levels or conditions, depending upon the extent of the ageing heat treatment.
The alloy is used in the Oil and Gas and chemical production industries on account of its high strength and resistance to chlorides, stress corrosion and sulphide stress cracking. Applications include valve trim, pump shafts and down-hole components. Alloy 718 is also used in jet engine and high-speed airframe parts such as wheels, spacers and buckets plus high-temperature bolts and fasteners.
Alloy 718 can be readily machined in either annealed or age-hardened conditions. Age-hardened conditions give a better surface finish with the annealed condition giving a longer tool life.
Inconel is a trademark of Special Metal Inc, covering a family of nickel-chromium alloys.