Patriot Bolt machines Hastelloy C-276 stud bolts from certified ASTM B574 round bar for flanges in the harshest chemical service. Alloy C-276 (UNS N10276) is a low-carbon nickel-molybdenum-chromium alloy with tungsten. It resists strong oxidizers, reducing acids, wet chlorine and chlorides, which is why it is often the material of last resort when other alloys fail.
We make C-276 studs to the specification on your purchase order or to your drawing. Every order ships with mill test reports traceable to the heat.
Hastelloy C-276 Stud Bolts at a Glance
- Also called
- Alloy C-276 · UNS N10276 · W.Nr. 2.4819
- Material specs
- ASTM B574 / ASME SB574 bar · ASTM F468 (Ni 276) · NACE MR0175 / ISO 15156-3
- Strength
- 100 ksi min tensile, 41 ksi min yield (ASTM B574, solution annealed)
- Corrosion
- Wet chlorine, hypochlorite, ferric and cupric chlorides, sulfuric and hydrochloric acids
- Configurations
- Fully threaded, double-end and tap-end
Why Engineers Specify Hastelloy C-276 Stud Bolts
In mixed or upset chemical service, the stud is often the part that fails first. Fluids wick into the threads and the flange crevice, and conditions can swing between oxidizing and reducing. C-276 handles both.
- Broad acid resistance. About 16% molybdenum and 15.5% chromium resist both reducing acids and strong oxidizers.
- Chlorine and chlorides. It is one of the few alloys that withstands wet chlorine gas, hypochlorite and chlorine dioxide.
- Pitting and stress-corrosion cracking. It resists pitting and chloride stress-corrosion cracking where stainless steels fail.
- Low carbon. Very low carbon and silicon limit grain-boundary precipitation after heat exposure.
Hastelloy C-276 Stud Bolt Specifications
C-276 bolting is usually ordered to ASTM B574 bar. ASTM F468 also covers nonferrous bolts and studs in C-276 (alloy Ni 276), with full-size test requirements.
| Specification | Tensile | Yield (0.2%), min | Elongation, min | Hardness |
|---|---|---|---|---|
| ASTM B574, solution annealed bar | 100 ksi min | 41 ksi | 40% | — |
| ASTM F468, Ni 276 | 110–140 ksi | 45 ksi | 25% | 20–32 HRC |
Annealed C-276 is much weaker than B7. For high-preload joints, confirm the stud size and torque with your engineer.
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 |
Typical limits for UNS N10276. The mill test report for your heat is the controlling document.
Stud Configurations
- Fully threaded studs, threaded end to end, for flange bolting where grip length varies.
- Double-end studs, threaded on both ends with an unthreaded center.
- Tap-end studs, with one end made to thread into a tapped hole.
C-276 can gall. Use a compatible thread lubricant or anti-seize.
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.
Compare Hastelloy C-276 with other bolting grades in our Fastener Materials Matrix.
Hastelloy C-276 Stud Bolts FAQ
Is Hastelloy C-276 the same as Alloy C-276?
Yes. HASTELLOY is a trade name. Alloy C-276, Hastelloy C-276 and UNS N10276 all refer to the same alloy.
When should I use C-276 instead of Inconel 625 studs?
C-276 has more molybdenum and adds tungsten, so it is often chosen for reducing acids, wet chlorine and mixed chemical service. 625 is stronger and is common in seawater and subsea work.
Is C-276 approved for sour service?
Alloy C-276 is listed in NACE MR0175 / ISO 15156-3 for hydrogen sulfide environments, within the limits that standard sets.
Do you make matching nuts?
Yes. We also machine Hastelloy C-276 nuts, so the stud and nut can come from one source.
Request a Quote
Send us the stud configuration, diameter, length, thread, specification and quantity, or upload your drawing. Our team will confirm the material and lead time. Call (281) 581-0176 or request a quote.
Also in Hastelloy C-276: Socket head cap screws · Hex head cap screws · Nuts · All stud bolts