Alloy 718 - UNS N07718
Nickel-chromium-molybdenum alloy 718, also called Nickel 718 and Inconel 718, is a Gamma Prime strengthened alloy with excellent mechanical properties at elevated temperatures, as well as cryogenic temperatures. Suitable for temperatures upto around 1300° F. Can be readily worked and age hardened.
Excellent strength from -423 degrees F to 1300 degrees F (-253 degrees C to 705 degrees C). Age hardenable and may be welded in fully aged condition, Excellent oxidation resistance up to 1800 degrees F (980 degrees C). Typically sold in the solution annealed temper, but can be ordered aged, cold worked, or cold worked & aged.
Alloy 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.
- Good mechanical properties: tensile, fatigue and creep-rupture.
- Excellent welding characteristics, resistant to postweld age cracking.
- Oxidation resistant throughout its useful temperature range.
Uses for this alloy tend to be in the field of gas turbines components and cryogenic stroage tanks. Jet engines, pump bodies and parts, rocket motors and thrust reversers, nuclear fuel element spacers, hot extrusion tooling. Other popular uses are high strength bolting, and down hole shafting.
|Ni + Co||Cr||Cb + Ta||Ma||Ti||Al||Co||C||Mn||Si||P||S||B||Cu||Fe|
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.
|Ultimate Tensile (ksi)||Yield Strength (ksi)||Elong. % in 2 in.|
HPA also does a full line of high strength Nickel based alloys.
The typical properties listed on page one can be provided in rounds, sheet, strip & plate. We have the equipment to produce small quantities in special sizes to meet our customers’ specific needs.
|Metal Type||UNS N07718|
|Bar||ASTM B637 AMS 5662 AMS 5663 AMS 5664 PWA 1009 PWA 1010 GE B50TF15|
|Sheet||ASTM B670 AMS 5596 AMS 5597 PWA 1033 GE B50TF14 ASTM B670 ASTM B637|
|Plate||ASTM B670 AMS 5596 AMS 5597 PWA 1033 GE B50TF14 ASTM B670 ASTM B637|
|Pipe||AMS 5589 AMS 5590|
|Tube||AMS 5589 AMS 5590|
|Forging||ASTM B637 AMS 5562 AMS 5663 AMS 5664 PWA 1009 PWA 1010 GE B50TF15|
|Weld Wire||A5.14 ERNiFeCr-2|
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. Detailed machining parameters are presented Tables 16 and 17. General plasma cutting recommendations are presented in Table 18.