Guides / Materials

Inconel 718 on 5-Axis Machines: What to Expect

September 26, 2026

Inconel 718 shows up on drawings for a reason: it holds strength at temperatures that would soften most other alloys, which is why it appears in turbine, aerospace and high heat industrial parts. That same property is what makes it one of the more demanding alloys a 5-axis shop quotes.

Why it cuts the way it does

Inconel 718 work hardens as the tool passes over it, meaning the surface gets harder from the cutting action itself. A tool that dwells too long or runs too slow can harden the material faster than it removes it, which then damages the next pass. It also has low thermal conductivity, so heat concentrates at the cutting edge instead of leaving with the chip, accelerating tool wear.

The practical result: cycle times on Inconel 718 commonly run three to six times longer than the same geometry in aluminum, and tool costs run higher because inserts wear out faster and need more frequent replacement.

What it means for the setup

Rigid fixturing matters more on Inconel than on almost any other common alloy, since any deflection under cutting forces both hurts finish and accelerates tool failure. Shops that run it regularly use lower cutting speeds, sharper coated tools and more conservative stepover than they would for steel of similar hardness. First article proof-out often takes longer, since speeds and feeds get dialed in specific to the geometry rather than reused from a standard recipe.

Tolerance and finish

±0.025 mm is a realistic target for critical features, tighter than that adds meaningful cost since finishing passes have to run slower and lighter to protect both the tool and the part surface. Surface finish as-machined is comparable to what a shop achieves on stainless steel, though getting there takes longer.

Typical Inconel 718 parts

• Turbine and compressor components
• High temperature aerospace brackets and fittings
• Oil and gas downhole tooling
• Nuclear and high heat industrial hardware

Cost and lead time

Inconel 718 costs more per kilogram of raw material than aluminum or stainless, and costs more per hour of machine time on top of that. Lead time often runs longer too, both because the material itself may need to be ordered and because fewer shops actively run it, which narrows the field willing to quote quickly.

What to send with your RFQ

Confirm whether the part needs a material certificate, common for aerospace and energy applications, and state it on the RFQ rather than assuming it. If your design allows a choice between Inconel and a less demanding alloy, ask the shop for the real price difference before assuming Inconel is required.

The short version

Inconel 718 is not harder to hold a tolerance on than other alloys, it is harder to cut, which shows up as more machine time, faster tool wear and more careful setup. Confirm material certification needs and a realistic tolerance up front, and expect the quote and lead time to reflect the alloy, not the shop being difficult.

Frequently asked questions

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