[ Nuts ]
Hastelloy C-22 Heavy Hex Nuts
Patriot Bolt machines Hastelloy C-22 heavy hex nuts from certified ASTM B574 bar (UNS N06022). C-22 nuts pair with C-22 studs so the whole joint has the same resistance to pitting, crevice corrosion and mixed acids.
We make C-22 nuts alone or with matching studs. Every order ships with mill test reports traceable to the heat.
[ Quick Specs ]
Hastelloy C-22 Heavy Hex Nuts at a Glance
- Material
- Hastelloy C-22, UNS N06022
- Bar specification
- ASTM B574 / ASME SB574
- Style
- Heavy hex to ASME B18.2.2
- Key elements
- 20–22.5% Cr, 12.5–14.5% Mo, 2.5–3.5% W
- Matching stud
- C-22 stud bolts
Why Engineers Specify C-22 Nuts
- Same alloy as the stud. Matching nut and stud material avoids galvanic corrosion in acid and chloride service.
- Crevice resistance. The nut face and threads trap fluid. C-22 resists the pitting and crevice attack that starts there.
- Galling. Like other nickel alloys, C-22 can gall. Use a compatible anti-seize on assembly.
C-22 Bar Properties
Nuts are machined from ASTM B574 bar, which sets these minimum properties.
| Specification and condition | Tensile, min | Yield (0.2%), min | Elongation, min |
|---|---|---|---|
| ASTM B574, solution annealed bar | 100 ksi | 45 ksi | 45% |
Hastelloy C-22 Chemical Composition
| Element | Weight % |
|---|---|
| Nickel | Balance |
| Chromium | 20.0–22.5 |
| Molybdenum | 12.5–14.5 |
| Tungsten | 2.5–3.5 |
| Iron | 2.0–6.0 |
| Cobalt | 2.5 max |
| Manganese | 0.50 max |
| Vanadium | 0.35 max |
| Silicon | 0.08 max |
| Carbon | 0.015 max |
| Phosphorus | 0.02 max |
| Sulfur | 0.02 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: Mixed-acid, chlorinated and oxidizing process flanges. See Petrochemical & Refining.
- Pollution control: Scrubber and ducting flanges.
- Sour oil and gas: Flanges in H2S and chloride service, within NACE MR0175 limits. See Oil & Gas.
Certification and Traceability
Patriot Bolt is ISO 9001:2015 certified. Each Hastelloy C-22 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-22 with other bolting grades in our Fastener Materials Matrix.
Hastelloy C-22 Heavy Hex Nuts FAQ
Should C-22 nuts be used with C-22 studs?
Yes. Matching materials avoid galvanic corrosion and keep the whole joint at the same corrosion resistance.
Can C-22 nuts be used on C-276 studs?
The two alloys are close in corrosion behavior and are sometimes mixed, but most specifications call for matching materials. Follow your project specification.
What bar specification is used?
ASTM B574 / ASME SB574, which covers UNS N06022 bar.
Do you make matching C-22 studs?
Yes. We machine Hastelloy C-22 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.