Inconel CNC Machining
718 & 625 Superalloy Parts
Nickel superalloys punish sloppy machining. We mill and turn Inconel 718 and 625 with the rigid setups, tooling discipline and stress-aware process planning they demand, as a subcontractor for aerospace, energy and chemical-processing customers worldwide.
Ginwate provides Inconel CNC machining services from Dongguan, China, precision CNC milling and CNC turning of Inconel 718 and Inconel 625 to ±0.005 mm, from a single prototype to ongoing subcontract production. Every batch ships with EN 10204 3.1 mill certificates, CMM inspection reports on request, and full traceability from bar stock to finished part.
Machining Inconel is a different discipline from machining steel or aluminum. Nickel-based superalloys work-harden the moment a tool rubs instead of cuts, hold their strength at red heat, and wear out carbide many times faster than steel does. Shops that treat Inconel like tough stainless burn tools, blow tolerances, and miss deliveries, which is why most buyers hand nickel-alloy work to a machining subcontractor that runs it every week. Our 5-axis machining centers and turning cells run dedicated nickel-alloy tooling and process sheets, so quoted prices and delivery dates hold.
Typical Inconel parts we machine include turbine and compressor components, combustor hardware, valve trim and seats, downhole oil-and-gas tools, exhaust and bellows components, and marine hardware, for aerospace, energy and chemical-processing customers in North America, Europe and Australia.
Inconel Grades We Machine
Both major grades are stocked in bar and plate; related nickel alloys are sourced to order with full mill certification.
| Grade | Condition | Hardness | Character | Typical parts |
|---|---|---|---|---|
| Inconel 718 | Solution annealed / aged | 36-45 HRC (aged) | Age-hardenable Ni-Cr superalloy; the aerospace workhorse for parts serving up to ~700 °C. | Turbine and compressor components, fasteners, downhole tools, high-temp fixtures |
| Inconel 625 | Annealed | ≤ 240 HB | Solid-solution strengthened; outstanding corrosion and seawater resistance without heat treatment. | Chemical processing, marine hardware, exhaust and bellows components |
| Monel 400 / Hastelloy | Per spec | Per spec | Related Ni-alloys we machine on request under the same process controls. | Valves, pumps, chemical plant components |
Why Inconel Machining Is Hard, and How We Do It
Superalloys reward process discipline and punish improvisation. These are the four battles every Inconel part goes through, and our standard answers to them.
Work hardening
Inconel hardens ahead of the cutting edge if tools rub instead of cut. We run rigid setups with positive-geometry carbide and ceramic tooling, and never let an edge dwell.
Heat at the cutting zone
With thermal conductivity around a tenth of aluminum's, heat concentrates in the tool. Lower surface speeds, strong chip loads, and high-pressure coolant keep edges alive.
Tool wear economics
Tooling cost per part is many times that of steel. Our process plans budget tool life per feature, so quoted prices hold and finish quality stays consistent to the last part.
Tolerance under stress
Residual stress can move a superalloy part after roughing. Critical Inconel parts are roughed, stress-settled, then finish-machined to hold ±0.005 mm where it matters.
Inconel 718 vs 625: Which Should You Specify?
Choose Inconel 718 when the part needs strength: it age-hardens to 36-45 HRC and keeps that strength up to roughly 700 °C, which is why it dominates turbine, fastener and downhole-tool work. It is the harder of the two to machine, especially in the aged condition, so critical dimensions are finish-machined after heat treatment.
Choose Inconel 625 when the enemy is corrosion: it needs no heat treatment, welds easily, and shrugs off seawater, chlorides and aggressive process chemistry, the natural pick for marine hardware, chemical plant components, and exhaust or bellows parts. It machines somewhat more predictably than aged 718, though it is gummier in the annealed state. If you are unsure, tell us the operating temperature and environment with your RFQ and we will confirm the grade during the free DFM review.
Inconel Machining Speeds & Feeds
Starting points for annealed Inconel 718 with rigid workholding, the parameters we begin from before tuning per feature. Aged material runs slower.
| Operation | Tooling | Cutting speed | Key rule |
|---|---|---|---|
| Milling — roughing | Coated carbide | 20–25 m/min (65–80 SFM) | Climb mill, chip load ≥ 0.05 mm/tooth so the edge cuts under the work-hardened layer |
| Milling — finishing | Sharp positive carbide | 25–35 m/min | Light radial engagement, high-pressure coolant straight at the cutting zone |
| Milling — roughing | Ceramic (SiAlON) | 150–300 m/min | Run dry in short bursts; for bulk stock removal on rigid setups only |
| Turning | Coated carbide | 30–50 m/min | Feed ≥ 0.15 mm/rev; never let the insert dwell or rub |
| Drilling | Carbide, through-coolant | 15–20 m/min | Peck cycles with through-tool coolant; back out before the corner loads up |
Inconel Machining Specifications
Inconel Machining FAQ
Do you machine Inconel 718 and 625?+
Yes. Inconel 718 and 625 are the two grades we machine most, alongside related nickel alloys such as Monel 400 and Hastelloy on request. Both milling and turning, prototypes through production.
Is Inconel hard to machine?+
Yes, Inconel is among the most difficult common engineering alloys to machine, with a machinability rating around 10-15% of free-machining steel. It work-hardens ahead of the cutting tool, keeps its strength at cutting temperatures, and its low thermal conductivity drives heat into the tool edge instead of the chip. It machines reliably with rigid setups, sharp positive-geometry carbide or ceramic tooling, and disciplined speeds and feeds, which is why most companies send Inconel parts to a specialist machining subcontractor rather than running them in-house.
What speeds and feeds should I use for machining Inconel 718?+
As a starting point for annealed Inconel 718: carbide milling at 20-35 m/min (65-115 SFM) with a chip load of at least 0.05 mm per tooth, carbide turning at 30-50 m/min with feeds of 0.15 mm/rev or more, and ceramic roughing at 150-300 m/min run dry. The rule that matters most is to keep the tool cutting under the work-hardened layer, light feeds that let the edge rub will harden the surface and destroy the next pass. Aged 718 (36-45 HRC) runs slower still.
Can you work as an Inconel machining subcontractor for ongoing production?+
Yes. We run ongoing subcontract production for overseas customers: fixed process sheets, CMM reports with every shipment, full material traceability, and DDP delivery. A single trial part is a normal way to start.
What tolerances can you hold on Inconel parts?+
Standard ±0.01 mm, ±0.005 mm routinely on critical dimensions, and ±0.001 mm on selected critical features. Superalloy parts are roughed and finish-machined separately to manage residual stress.
Why is Inconel machining more expensive than steel?+
Tool wear is the driver: cutting speeds are a fraction of steel's and inserts wear many times faster, so machine time and tooling per part are both higher. Good DFM, generous radii, realistic tolerances, honest surface-finish callouts, reduces cost meaningfully.
Do you supply material certificates for Inconel?+
Yes. Mill certificates (EN 10204 3.1) accompany the raw material, and each shipment can include CMM dimensional reports and full traceability from bar to finished part.
Related Capabilities
Have an Inconel part to quote?
Upload your CAD and drawing, an engineer reviews DFM and returns a detailed quote within 24 hours. Single trial parts welcome.
Get a Free Quote