Inconel 718 3D printing, on a 400 mm platform.
The nickel superalloy that turbine and rocket engine hardware is made of, printed by laser powder bed fusion, heat treated to the wrought specification and machined only where it matters.
Inconel 718 is the most printed superalloy in the world for a reason: it holds its strength to around 650 °C, it resists oxidation and corrosion, it stays ductile at cryogenic temperatures, and it welds, which means it prints. AME runs it on an EOS M 400 in Huntsville, Alabama.
- Service temperature
- 650°C structural, 1200 °F
- Minimum UTS
- 1240MPa, ASTM F3055 after HIP and age
- Density
- 8.19g/cm³
- Cryogenic
- −253°C, still ductile
What Inconel 718 is.
Inconel 718 (UNS N07718, also alloy 718 or IN718) is a precipitation hardened nickel chromium iron superalloy. Roughly half nickel, a fifth chromium, a fifth iron, with niobium, molybdenum, titanium and aluminium doing the work. Niobium is the key: on ageing it forms gamma double prime (Ni3Nb) precipitates that give the alloy its strength, and it forms them slowly, which is what makes 718 weldable and, by extension, printable where other superalloys crack.
| Nickel | 50.0 to 55.0 |
|---|---|
| Chromium | 17.0 to 21.0 |
| Iron | Balance |
| Niobium (plus tantalum) | 4.75 to 5.50 |
| Molybdenum | 2.80 to 3.30 |
| Titanium | 0.65 to 1.15 |
| Aluminium | 0.20 to 0.80 |
| Cobalt | 1.00 max |
| Carbon | 0.08 max |
Properties that matter for printed parts.
| Designation | UNS N07718; alloy 718; IN718 |
|---|---|
| Density | 8.19 g/cm³ (0.296 lb/in³) |
| Melting range | 1260 to 1336 °C |
| Service temperature | Structural to about 650 °C (1200 °F); oxidation resistant beyond |
| Cryogenic | Retains strength and ductility to −253 °C |
| Tensile, HIP plus solution and age | UTS 1240 to 1400 MPa; yield 920 to 1230 MPa; elongation 12 to 20 percent, by heat treatment and orientation |
| ASTM F3055 minimums | UTS 1240 MPa, elongation 12 percent, after HIP, solution and age |
| Hardness after ageing | About 40 HRC |
| Corrosion | Good in oxidising and reducing environments; resists stress corrosion cracking |
| Weldability | Excellent; slow gamma double prime kinetics, which is why it prints |
ASTM F3055 is the specification for 718 made by powder bed fusion. It defines the heat treatment classes and the minimum tensile properties a printed part must meet; AMS 5662 and 5663 are the wrought references the industry compares against. Properly HIP’d and aged LPBF 718 meets those minimums. Program allowables come from your own coupon testing.
How we print it.
Inconel 718 runs on our EOS M 400 with a 1 kW laser, 40 micron layers and an argon atmosphere. Parts come off the plate at better than 99.5 percent density. Powder lots are traced from certificate to build, and parameters are locked once a part is qualified, so a repeat run twelve months later is the same part.
Because 718 is age hardened, sequence matters. A common route for a flight part is:
- Stress relief on the plate.
- Removal from the plate by wire EDM.
- Support removal and any rough machining, while the alloy is still soft.
- Hot isostatic pressing to close porosity, typically around 1160 °C at 100 MPa.
- Solution treatment near 955 to 980 °C, then a double age near 720 °C and 620 °C, about 18 hours in total, per AMS 2774 and ASTM F3055.
- Finish machining, inspection, surface finishing.
Machining after ageing is possible but slow; 718 is one of the harder alloys on cutters. Printing near net shape and leaving stock only on interfaces is where the process pays for itself.
What people print in 718.
- Rocket engine injectors, manifolds, turbopump housings and ducts.
- Gas turbine cases, vanes, seals and brackets.
- Valve bodies and fittings for cryogenic and hot gas service.
- Heat exchangers with printed in passages.
- Tooling and fixtures that see heat.
- Test articles and prototypes for materials programs.
Inconel 718 against Inconel 625.
625 is solid solution strengthened and cannot be aged; it is easier to print, more corrosion resistant, and weaker. 718 is age hardened to roughly twice the yield strength and is the choice for structural parts to 650 °C. If the part is a hot gas path fitting with no real load, 625 is fine. If it is a housing under pressure at temperature, it is 718.
Design notes for printed 718.
- Walls: 0.5 mm minimum, 1 mm comfortable. Keep sections consistent.
- Supports on anything that overhangs more than 45 degrees; chamfer or teardrop where you can.
- Residual stress is high in 718. Avoid long unsupported spans; expect stress relief before the part leaves the plate.
- Add 0.5 to 1 mm of machining stock on sealing faces, bores and fits.
- Thread after machining, not in the print.
- Give every internal cavity a powder escape hole.
The full set of rules is on the laser powder bed fusion page. We check them before quoting.
Questions we get asked.
Can Inconel 718 be 3D printed?
Yes. It is one of the most established alloys in laser powder bed fusion. Its strengthening phase forms slowly, which makes 718 weldable and therefore printable without the cracking that troubles many other superalloys.
How strong is 3D printed Inconel 718?
After hot isostatic pressing, solution treatment and ageing, ultimate tensile strength is above 1240 MPa and yield above about 900 MPa, with elongation of 12 percent or more. That meets the ASTM F3055 minimums for powder bed fusion 718 and is comparable to wrought AMS 5662 material.
What temperature can Inconel 718 withstand?
It carries structural load to around 650 °C (1200 °F) and resists oxidation well beyond that. Above about 650 °C the strengthening precipitates begin to coarsen and strength falls. It also stays ductile down to liquid hydrogen temperature, which is why it is used in cryogenic rocket hardware.
Is Inconel 718 hard to 3D print?
It is easier than most superalloys. The work is in managing residual stress, which is high, and in sequencing heat treatment and machining correctly. Cracking is not the problem it is with the higher gamma prime alloys.
How much does Inconel 718 3D printing cost?
More than stainless or aluminium: the powder costs several times as much and the part needs HIP, solution and age, and machining on interfaces. Small parts start in the hundreds of dollars, complex hardware in the thousands. See the cost guide for what moves the number.
Does 3D printed Inconel need heat treatment?
Yes, for any structural use. Stress relief is always done before parts are cut from the plate. Solution treatment and ageing develop the strength. HIP is added for fatigue critical and pressure boundary parts.
Inconel 718 or titanium?
Ti-6Al-4V is about half the density and is the choice for light structures that stay below roughly 350 °C. Inconel 718 is the choice when the part runs hot, sees hot gas, or has to hold pressure at temperature. AME runs 718; titanium can be brought on for programs with the volume.
Go deeper.
GRCop-42 3D printing
NASA’s copper alloy for chamber liners and injectors.
ProcessLaser powder bed fusion
How the machine works, the design rules, and LPBF next to powder metallurgy.
ServiceMetal 3D printing service
What the job includes, the specifications, and how to choose a shop.
PricingMetal 3D printing cost
Six cost drivers, typical ranges, and how to bring the number down.
PrimerMetal additive manufacturing
The process families, the standards, and where laser powder bed fusion fits.
LocationMetal 3D printing in Huntsville, AL
Next to Redstone Arsenal and Marshall. Visit the shop.
Request a quote
Send the 718 part. We’ll tell you if it builds.
Pricing, a heat treatment route and an honest read on the geometry, from an engineer.