[ Nuts ]
Hastelloy C-276 Heavy Hex Nuts
Patriot Bolt machines Hastelloy C-276 heavy hex nuts from certified ASTM B574 bar (UNS N10276). C-276 nuts pair with C-276 studs for flanges in wet chlorine, strong acids and mixed chemical service.
We make C-276 nuts to ASTM F467, to B574 bar properties or to your drawing, alone or with matching studs. Every order ships with mill test reports traceable to the heat.
[ Quick Specs ]
Hastelloy C-276 Heavy Hex Nuts at a Glance
- Material
- Hastelloy C-276, UNS N10276
- Specifications
- ASTM F467 (Ni 276) · ASTM B574 / ASME SB574 bar
- F467 requirements
- 110 ksi min proof stress (hex), 20 HRC min
- Style
- Heavy hex to ASME B18.2.2
- Matching stud
- C-276 stud bolts
Why Engineers Specify C-276 Nuts
- Same alloy as the stud. Matching nut and stud material avoids galvanic corrosion in severe chemical service.
- Broad acid resistance. About 16% molybdenum and 15.5% chromium resist both reducing acids and oxidizers.
- Defined nut requirements. ASTM F467 lists C-276 as alloy Ni 276, with a proof stress and minimum hardness for each lot.
- Galling. C-276 can gall. Use a compatible anti-seize on assembly.
C-276 Nut Specifications
ASTM F467 covers nonferrous nuts from 1/4 to 1-1/2 in. Heavy hex nuts carry a proof stress 8 percent higher than regular hex because of their deeper thread engagement. Larger nuts are machined from ASTM B574 bar.
| Specification | Proof stress, min | Hardness, min | Tensile, min (bar) | Yield (0.2%), min (bar) |
|---|---|---|---|---|
| ASTM F467 Ni 276, hex | 110 ksi | 20 HRC | — | — |
| ASTM F467 Ni 276, heavy hex | 119 ksi | 20 HRC | — | — |
| ASTM B574 bar, solution annealed | — | — | 100 ksi | 41 ksi |
Put the specification on your purchase order so the nuts are made and tested to it.
Hastelloy C-276 Chemical Composition
| Element | Weight % |
|---|---|
| Nickel | Balance |
| Molybdenum | 15.0–17.0 |
| Chromium | 14.5–16.5 |
| Iron | 4.0–7.0 |
| Tungsten | 3.0–4.5 |
| Cobalt | 2.5 max |
| Manganese | 1.0 max |
| Vanadium | 0.35 max |
| Silicon | 0.08 max |
| Carbon | 0.010 max |
Limits per the current edition of the specification. The mill test report for your heat is the controlling document.
Nut Styles
- Heavy hex nuts to ASME B18.2.2, the standard style for flange studs.
- Heavy hex jam nuts where a thinner nut is needed.
- Threads: UNC through 1 in and 8UN above 1 in, or the thread on your drawing.
Applications and Industries
- Chemical processing: Chlorination, acid and mixed-chemical service. See Petrochemical & Refining.
- Pollution control: Flue gas desulfurization scrubbers and ducting.
- Sour oil and gas: Wellhead and process flanges in H2S service. See Oil & Gas.
Certification and Traceability
Patriot Bolt is ISO 9001:2015 certified. Each Hastelloy C-276 order includes mill test reports traceable to the heat, along with a certificate of conformance to the specification on your purchase order.
Nuts are marked with the material and our identification.
Compare Hastelloy C-276 with other bolting grades in our Fastener Materials Matrix.
Hastelloy C-276 Heavy Hex Nuts FAQ
Which specification covers C-276 nuts?
ASTM F467 covers C-276 nuts as alloy Ni 276, from 1/4 to 1-1/2 in. Larger nuts are machined from ASTM B574 bar.
How strong are C-276 nuts?
Under ASTM F467, Ni 276 nuts have a 110 ksi minimum proof stress for hex nuts and 20 HRC minimum hardness. Heavy hex nuts are rated 8 percent higher.
Should C-276 nuts be used with C-276 studs?
Yes. Matching materials avoid galvanic corrosion and keep the whole joint at the same corrosion resistance.
Do you make matching C-276 studs?
Yes. We machine Hastelloy C-276 stud bolts, so the stud and nuts can come from one source.
Request a Quote
Send us the alloy, nut style, thread size, specification and quantity, or upload your drawing. Our team will confirm the material and lead time. Call (281) 581-0176 or request a quote.