NI · superalloy
Nickel Alloy Hastelloy C-276 (UNS N10276)
One of the hardest materials in this catalogue: very tough, work-hardening, and abrasive. It machines slowly and it consumes tooling regardless of what you do.
Quoting this material
- Typical lead time
- 25–40 working days
- Condition
- Annealed
- Achievable finish
- Ra 1.6 µm typical · Ra 0.8 µm best
Machined in-house to your drawing: see the precision CNC machining service and the machine and inspection capability it runs on.
Machinability
Our own 1–10 shop ranking, not a published index: 10 is free-cutting brass C360, 1 is Inconel 718. It ranks how a material behaves on the floor - cycle time, chip control and tool life together. Where a published index exists it is quoted in the note.
One of the hardest materials in this catalogue: very tough, work-hardening, and abrasive. It machines slowly and it consumes tooling regardless of what you do.
Properties as supplied
| Parameter | Value | Unit |
|---|---|---|
| Tensile strength | 790 | MPa |
| Yield strength (0.2%) | 355 | MPa |
| Elongation | 40 | % |
| Hardness | ~190 | HB |
| Corrosion service | Oxidising and reducing media | - |
| Thermal conductivity | 10.2 | W/m·K |
Hardness, tensile and thermal figures are typical published values for the condition stated. Actual mill certificates govern; send the specification with the drawing and we confirm against the certificate before the material is cut.
Condition
Annealed
Heat treatment
Solid-solution strengthened; no ageing. The alloy is designed for corrosion resistance across a wide range of media and retains that resistance as welded without a post-weld heat treatment - which is a large part of its value.
Achievable surface finish
Ra 1.6 µm
Ra 0.8 µm
Surface finish affects the corrosion resistance directly: a torn or smeared surface has less effective chromium and molybdenum at the surface than a cleanly cut one.
Tooling and cutting parameters
Cutting speed
- 15–35 m/min (carbide)
Feed
- 0.06–0.15 mm/rev turning · 0.04–0.10 mm/tooth milling
Tooling
- Fine-grain carbide, tough substrate, sharp positive geometry; expect to consume tooling
Coolant
- High-pressure flood, through-tool where possible
Starting points for carbide on a rigid setup, not a guarantee. The right numbers depend on the machine, the toolholder and the fixturing - ask and we will say what we would actually run.
Typical applications
- Chemical reactor internals
- Flue gas desulphurisation components
- Pharmaceutical process equipment
- Offshore sour gas hardware
- Pollution control scrubbers
DFM notes for this grade
- The reason to buy it is a chemical environment that destroys everything else - if a 625 or a 316L would survive, the C-276 is not earning its cost
- It work-hardens severely, so a running-in cut or a dwell will harden the surface beyond what the tool can cut
- Surface integrity matters for corrosion: rough machining leaves a surface that initiates pitting in chloride service
Questions buyers ask
- Why is C-276 so widely specified in chemical service?
- Because it handles both oxidising and reducing media in one alloy and keeps its corrosion resistance as welded. Most alloys are good in one family of chemistries; C-276 is the general-purpose answer when the process recycles and the chemistry shifts.
- Is there any way to machine it faster?
- Not much. The published numbers put it in the same bracket as 718: low speed, high pressure coolant, sharp geometry and short tool life. What you can control is the number of operations - every setup you design out is a real saving on a part like this.
Grades we would quote instead
Hastelloy X
2/10A nickel-chromium-iron-molybdenum alloy for high-temperature structural service.
Inconel 625
2/10Harder to machine than the 600-series grades and easier than 718.
Monel 400
3/10The 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.