NI · 10 grades
Nickel Superalloys
The materials that keep their strength when everything else has given up.
Nickel superalloys are specified for hot sections, corrosive service and anywhere a part has to hold strength at 600–1000 °C. They pay for it on the machine: Inconel 718 work-hardens almost instantly, so a tool that rubs for one revolution has already ruined the surface. Everything about machining them - rigidity, feed rate, tool path - is designed to keep the cutter under the work-hardened layer.
What this family does well, and where it bites
- Strength retained to 700 °C and beyond, where steel has long since crept
- Work-hardens on contact: light passes and dwelling are how parts get scrapped
- Ceramic and whisker-reinforced tooling for roughing hardened or cast forms
- Certified, heat-lot traceable stock only - substitutions are not acceptable
Industries served
- Aerospace
- Energy & Oil & Gas
- Chemical Processing
- Power Generation
- Marine
Nickel Superalloys grades we machine
Each grade page carries the properties as supplied, what heat treatment does or does not do to it, the achievable surface finish, starting cutting parameters and the DFM notes that matter for that specific grade.
Inconel 718
1/10~331 HB (~36 HRC aged) · 1,240–1,300 MPa (aged)
The bottom of our scale and the reason the scale exists.
Inconel 625
2/10~200 HB (annealed) · 930 MPa
Harder to machine than the 600-series grades and easier than 718.
Inconel 600
2/10~175 HB · 655 MPa
The mildest of the common nickel alloys to machine - still awkward, but it work-hardens less aggressively than 625 and far less than 718.
Inconel 738
1/10~380 HB (cast and aged) · ~1,000 MPa (cast, at room temperature)
A cast nickel superalloy for turbine blades, supplied as a casting rather than bar.
Monel 400
3/10~150 HB · 550 MPa
The most forgiving of the nickel alloys: it machines closer to a tough stainless than to a superalloy, although it work-hardens and galls like its relatives.
Hastelloy C-276
1/10~190 HB (annealed) · 790 MPa
One of the hardest materials in this catalogue: very tough, work-hardening, and abrasive.
Hastelloy X
2/10~180 HB · 760 MPa
A nickel-chromium-iron-molybdenum alloy for high-temperature structural service.
Waspaloy
1/10~36–40 HRC (aged) · 1,275 MPa (aged)
A precipitation-hardened nickel alloy for turbine discs: harder than 718 at temperature and comparable to machine, which is to say slowly and with planned tool consumption.
Nimonic 80A
1/10~35–40 HRC (aged) · 1,100 MPa (aged)
A precipitation-hardened nickel-chromium alloy for exhaust valves and high-temperature springs.
Incoloy 825
2/10~200 HB · 620 MPa
A nickel-iron-chromium alloy with molybdenum and copper: easier to machine than the nickel-rich superalloys and still resistant to a wide range of corrosive media.
Questions buyers ask
- Why is Inconel 718 so much harder to machine than titanium?
- It keeps its strength at temperatures where titanium has softened. Titanium is hard on the tool because it does not carry heat away; Inconel is hard on the tool because the chip is still strong and abrasive when it leaves the cut, and the alloy strain-hardens the moment the tool stops cutting cleanly.
- Can you machine Inconel castings as well as bar stock?
- Yes, but the cast skin is abrasive and often has to be removed with a ceramic insert before any finishing pass. Cast superalloy also behaves differently lot to lot, so we would want the casting specification and heat lot before quoting a finished dimension.