Inconel® 718
Inconel® 718 - UNS N07718 - W. Nr. 24668 - Nickel Alloy 718 - NiCr Alloy
Home > All Alloys > Inconel® 718
| Table of Contents | |
|---|---|
| Datasheet | Chemistry |
| Inventory | Applications |
| General Data | Mechanical Properties |
| Specifications | Machining, Welding, & Processing |
| References | |
Nickel-chromium-molybdenum alloy 718 is a Gamma Double Prime strengthened alloy with excellent mechanical properties at elevated temperatures, as well as cryogenic temperatures. Suitable for temperatures up to around 1300 °F. Can be readily worked and age hardened.
Excellent strength from -423 °F to 1300 °F (-253 °C to 705 °C). Age hardenable and may be welded in fully aged condition, Excellent oxidation resistance up to 1800 °F (980 °C). Typically sold in the solution annealed temper, but can be ordered aged, cold worked, or cold worked & aged.
Datasheet
View or download our 718 datasheet here
Chemistry*
| Min% | Max% | |
|---|---|---|
| Ni (+Co) | 50.00 | 55.00 |
| Cr | 17.00 | 21.00 |
| Fe | Bal. | |
| Nb (+Ta) | 4.75 | 5.50 |
| Mo | 2.80 | 3.30 |
| Ti | 0.65 | 1.15 |
| Al | 0.20 | 0.80 |
| Co | 1.00 | |
| C | 0.08 | |
| Mn | 0.35 | |
| Si | 0.35 | |
| P | 0.015 | |
| S | 0.015 | |
| B | 0.006 | |
| Cu | 0.30 |
Typical Inventory
Round Bar, Loose Coil, Plate, Billet
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Applications
Uses for this alloy tend to be in the field of gas turbine components and cryogenic storage tanks. Alloy 718 is commonly used in jet engines, pump bodies and parts, rocket motors and thrust reversers, and hot extrusion tooling. Other popular uses are high strength bolting and down hole shafting.
General Data
Alloy 718 is a high strength, nickel base, superalloy used for cryogenic temperatures up to long term service at 1200 °F. This alloy is readily fabricated and may be welded in either the annealed or precipitation hardened (aged) condition. 718 is annealed at 1700-1850 °F and air cooled or faster. It is aged at 1325 °F for 8 hours, furnace cooled to hold at 1150 °F, for a total aging time of 18 hours, then air cooled. Alloy 718 will show a contraction of 0.0008 inch/inch after precipitation hardening.
- Good mechanical properties: tensile, fatigue, and creep-rupture.
- Excellent welding characteristics and resistant to postweld age cracking.
- Oxidation resistant throughout its useful temperature range.
Mechanical Properties
The typical properties listed can usually be provided in rounds, sheet, strip, plate, & custom forgings. We have the equipment to produce small quantities in special sizes to meet our customers’ specific needs. The table below shows Special Metals' Nominal Room-Temperature Mechanical Properties of Alloy 718 Bars, Forgings, & Rings and Sheet, Strip, & Plate. For most common forms and exceptions, check out the datasheet linked underneath the table.
| Form | Spec. | UTS ksi (MPa) | YS ksi (MPa) | Elong. in 2 in., % | Reduced Area, % | Hardness |
|---|---|---|---|---|---|---|
| Bar, Forged, & Ring | AMS 5662 & 5663 | 180-185 (1241-1276) | 150 (1034) | 6-12 | 8-15 | 331 BHN |
| Sheet, Strip, & Plate | AMS 5596 | 180 (1241) | 150 (1034) | 12 | HRC 36 |
UTS = Ultimate Tensile Strength, YS = Yield Strength
Link to Special Metals' datasheet on Inconel® 718Common Specifications
Note that the specifications listed are common for this alloy but are for reference only and may be specific to a certain form. The specifications listed are not comprehensive nor indicative of any edition, revision, or similar such as an amendment. Please, reach out to our sales department to request the Material Test Report (MTR) or to confirm your required specifications.
| Form | Standard |
|---|---|
| Identification | UNS N07718, DIN 17744, DIN 17750-17754, W. Nr. 2.4668 |
| Bar | AMS 5662, AMS 5663, AMS 5664, ASTM B637, ASME SB637 |
| Sheet, Plate, or Strip | AMS 5596, AMS 5597, ASTM B670, ASME SB670 |
| Tube | AMS 5589, AMS 5590 |
| Forging | ASTM B637, AMS 5562, AMS 5663, AMS 5664 |
| Weld Wire | AWS A5.14 ERNiFeCr-2/ AMS 5832 |
Machining
Nickel and cobalt based alloys can be difficult to machinine. However, it should be emphasized that these alloys can be machined using conventional production methods at satisfactory rates. These alloys harden rapidly, generate high heat during cutting, weld to the cutting tool surface and offer high resistance to metal removal because of their high shear strengths. The following are key points which should be considered during machining operations:
- CAPACITY - Machine should be rigid and overpowered as much as possible.
- RIGIDITY - Work piece and tool should be held rigid. Minimize tool overhang.
- TOOL SHARPNESS - Make sure tools are sharp at all times. Change to sharpened tools at regular intervals rather than out of necessity. A 0.015 inch wear land is considered a dull tool.
- TOOLS - Use positive rake angle tools for most machining operations. Negative rake angle tools can be considered for intermittent cuts and heavy stock removal. Carbide-tipped tools are suggested for most applications. High speed tools can be used, with lower production rates, and are often recommended for intermittent cuts.
- POSITIVE CUTS - Use heavy, constant, feeds to maintain positive cutting action. If feed slows and the tool dwells in the cut, work hardening occurs, tool life deteriorates and close tolerances are impossible.
- LUBRICATION - lubricants are desirable. Soluble oils are recommended especially when using carbide tooling.
References
Link to Special Metals' datasheet on Inconel® 718Inconel® is a registered trademark of the Special Metals Corporation group of companies.
Data referring to mechanical properties and chemical analyses are the result of tests performed on specimens obtained from specific locations of the products in accordance with prescribed sampling procedures; any warranty thereof is limited to the values obtained at such locations and by such procedures. There is no warranty with respect to values of the materials at other locations.