UNS N07718 AMS 5589 Seamless Tube Nickel Alloys

The Composition of Nickel Inconel 718

The composition of the particular alloy is the following: 

*Not exclusively to the element mentioned, but that one predominates other elements that are used only in minimal quantities.

Fabrication and Working Instructions 

It is highly recommended to follow the next instructions when Nickel Inconel 718 is heated, in order to minimize oxide layers forming.

• Fuels used for the heating must be extremely low in sulfur;
• Both the furnace and material should be heated at the correct temperatures;
• Before putting it into the furnace, completelyclean the alloy from oil, paint, grease, and shop soil;
• For forging or open annealing, the furnace atmosphere should be slightly reducing, with at least 2% carbon monoxide;
• Keep the pressure in the furnace slightly positive so that there is no air infiltration;

Please note that in reducing atmospheres, a green-black film of oxide forms (easy to remove). In oxidizing atmospheres, on the other hand, a black scale forms that is very difficult to remove.

Nickel Inconel 718 joint efficiency when welding is about 100% for parts that have been annealed, welded and aged. Due to the slow response, it can be age-hardened directly, without any sort of stress relief. Welding should be done with the gas tungsten-arc process, using the proprietary Nickel Filler Metal 718.

If the Alloy Nickel Inconel 718 is cold-worked or precipitation hardened, use of silver brazing compounds is not recommended, as they can cause stress and crackling to the alloy. Brazing compounds with cadmium should also be avoided because that element can aggravate the cracking that started from silver or other elements.