Wexmar performs Inconel 718 CNC machining for aerospace hardware, defense components, fasteners, shafts and high-temperature fittings. Alloy 718 (UNS N07718) is a precipitation-hardenable nickel-chromium superalloy that keeps high strength to roughly 1300 F and resists creep and fatigue. It ranks among the harder alloys routinely cut in a production shop, and success depends on sequence and tooling discipline. We turn, mill and Swiss-machine 718 at our facility in Canastota, New York.
Inconel 718 machinability, annealed versus aged
Approximate ratings on the AISI 1212 = 100 scale are about 12 for solution-annealed 718 and about 8 for aged material, which typically runs near 40 HRC. The alloy combines hot hardness, rapid work hardening, abrasive carbides and low thermal conductivity, so the insert sees high heat and high pressure at the same time. Expect surface speeds well below those used on stainless steel and cycle times several times longer than the same geometry in alloy steel. Tool cost per part is a real line item on 718 quotes, and we price it honestly rather than assuming ideal tool life.
Machine before or after aging?
The main process decision on 718 is when to age. Roughing in the annealed condition is faster and easier on tooling, but aging causes slight size change and some distortion. A common sequence is to rough annealed, age through qualified outside processors, then finish critical features in the aged condition. Machining fully aged bar from the start avoids a heat treat round trip and is often sensible for small parts, at the cost of slower cutting. We state the chosen sequence on the quote.
Tolerances and finish
Typical tolerances are plus or minus 0.0005 in. on turned diameters and plus or minus 0.001 in. on milled features, including after aging when finish passes follow heat treatment. Typical finishes are 63 Ra as machined and 32 Ra on finished bores, seal diameters and bearing seats. Values are typical and depend on geometry and material condition.
Tooling and chip control in alloy 718
- Coated carbide with sharp but honed edges for finishing, and ceramic inserts for roughing annealed stock where setups are rigid.
- Constant chip load and no dwell, because a rubbing edge work hardens the surface and shortens the life of the next tool.
- High-pressure coolant aimed at the cutting zone to control heat and break the tough, springy chips.
- Planned insert indexing by part count rather than running to failure, which protects size and finish on long runs.
- Thread milling for internal threads in aged material, where tapping carries high breakage risk.
- Deburring programmed with chamfer tools, since 718 burrs are hard and will not brush off.
Heat treat and finish options
Bar is commonly ordered to AMS 5662 in the solution-treated condition or AMS 5663 in the aged condition. Solution treatment and precipitation aging to the specification on the drawing are performed through qualified outside processors, and their certs, including hardness results, ship with the parts. Passivation and other surface treatments are also arranged through qualified outside processors.
Common Inconel 718 parts
- Shafts, spindles and pins: CNC turning with live tooling
- High-strength fasteners, studs and bushings up to 32 mm diameter: Swiss machining
- Brackets, mounts and flanged housings: horizontal milling with pallet changers
- Spring retainers, seal rings and high-temperature fittings: CNC lathes
- Build-to-print defense and aerospace hardware with FAI in AS9102 format
Cost index versus 6061 aluminum
| Material | Approx. machinability (1212 = 100) | Cost index vs 6061 | Notes |
|---|---|---|---|
| Inconel 718 | ~12 annealed, ~8 aged | 8.0 | Age hardenable superalloy |
| Inconel 625 | ~15 | 7.0 | Used annealed, corrosion focus |
| Hastelloy C276 | ~12 | 9.0 | Chemical service |
| Monel K500 (aged) | ~15 | 6.0 | Nickel-copper, age hardened |
| Ti-6Al-4V | ~22 | 5.0 | Lighter, lower temperature limit |
| 17-4 PH stainless (Cond A) | ~40 | 2.8 | Lower cost PH option |
| 6061-T6 aluminum | ~180 | 1.0 | Cost index baseline |
The values are typical and illustrative for a comparable part; actual quotes depend on geometry, quantity, tolerances and mill pricing.
Industries served
Alloy 718 parts from our shop support aerospace hardware, defense and government build-to-print programs, industrial turbine and pump equipment, and instrumentation. DFARS 252.225-7009 specialty-metals-compliant sourcing is available, along with material certs, heat-lot traceability and CMM reports. Learn more about our government and defense machining. For parts that need corrosion resistance more than strength, compare Inconel 625.
Getting a quote
For aged Inconel 718 machining or annealed work, upload a drawing for an instant estimate or call (315) 400-2654. A human estimator confirms every quote, including heat treat sequence and material specification.