Hastelloy C-276 (UNS N10276)
The universal chemical-process alloy — resists oxidising and reducing acids, wet chlorine and sour gas — and the F468 fastener grade Ni 276.
What Hastelloy C-276 is.
Hastelloy C-276 is a nickel alloy with 16 percent molybdenum, 15.5 percent chromium and 3.7 percent tungsten, and a very low carbon and silicon content that keeps it free of grain-boundary precipitates after welding. That combination resists both oxidising and reducing environments: wet chlorine, hypochlorite, sulfuric, hydrochloric and phosphoric acids, and hydrogen sulfide.
ASTM B574 covers the rod; ASTM F468 covers C-276 fasteners as Ni 276. We machine C-276 studs, bolts, nuts and components from certified B574 rod.
Chemical composition.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Nickel | Ni | balance | — |
| Molybdenum | Mo | 15.0 | 17.0 |
| Chromium | Cr | 14.5 | 16.5 |
| Iron | Fe | 4.0 | 7.0 |
| Tungsten | W | 3.0 | 4.5 |
| Cobalt | Co | — | 2.5 |
| Manganese | Mn | — | 1.0 |
| Vanadium | V | — | 0.35 |
| Carbon | C | — | 0.010 |
| Silicon | Si | — | 0.08 |
| Phosphorus | P | — | 0.04 |
| Sulfur | S | — | 0.03 |
Values per ASTM B574-18 Table 1 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Mechanical properties.
| Condition and size | Tensile strength, min (ksi) | Yield strength 0.2%, min (ksi) | Elongation, min (%) |
|---|---|---|---|
| Solution annealed — all sizes | 100 | 41 | 40 |
Values per ASTM B574-18 Table 5 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
| Nominal diameter (in.) | Hardness | Full-size tensile (ksi) | Full-size yield, min (ksi) | Machined tensile, min (ksi) | Machined yield, min (ksi) | Elongation in 4D, min (%) |
|---|---|---|---|---|---|---|
| All sizes | 20–32 HRC | 110–140 | 45 | 110 | 45 | 25 |
Values per ASTM F468-23 Table 2 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team. Full-size tensile range and yield; machined-specimen minimums in the last three columns.
| Nut style | Hardness, min | Proof stress, min (ksi) |
|---|---|---|
| Hex and hex flange | 20 HRC | 110 |
| Heavy hex, large hex flange and thick | 20 HRC | 119 |
Values per ASTM F467-24 Table 2 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Specifications that apply.
How Hastelloy C-276 ships from Houston.
- Full-thread studs and stud bolts
- Hex and heavy hex bolts
- Socket head cap screws
- Hex nuts in the same alloy
- Threaded rod
- Machined components from certified bar
Hastelloy C-276 fasteners we make.
Every item is manufactured to your drawing or standard in Hastelloy C-276, imperial or metric, with an EN 10204 3.1 certificate.
What is Hastelloy C-276?
C-276 was the first of the modern low-carbon C-family alloys. Molybdenum and tungsten give it resistance to reducing acids and to pitting and crevice corrosion in chlorides; chromium gives resistance to oxidising media; and holding carbon below 0.01 percent and silicon below 0.08 percent prevents the carbide precipitation that made the original alloy C sensitive to welding. The result is a single alloy that handles most of the aggressive streams in a chemical plant. F468 lists it as Ni 276 with 110 to 140 ksi full-size tensile and 45 ksi yield.
Testing, certification and marking
- Tensile and hardness tested per lot on the finished product
- Grade or alloy marking F468T on bolts and F467T on nuts and manufacturer's identification on every piece
- EN 10204 3.1 material test report with heat number and chemistry; 3.2 witness available
Hastelloy C-22 (UNS N06022)
The higher-chromium C alloy — better than C-276 in oxidising acids, ferric and cupric chlorides and wet chlorine, with the same resistance to pitting and stress-corrosion cracking.
ASTM B335 rod · F468 / F467 list the related N10001 alloyHastelloy B-2 (UNS N10665)
The hydrochloric-acid alloy — 28 % molybdenum for all concentrations of HCl and other reducing acids — and the F468 fastener grade Ni 335.
ASTM B446 bar · ASTM F468 / F467 fastenersInconel 625 (UNS N06625)
The corrosion all-rounder — 120 ksi in the annealed condition, resistant to seawater, sour gas, acids and oxidation to 1800 °F, and the F468 nickel fastener grade Ni 625.