Hastelloy C22
Stud Bolts
UNS N06022
Why Specify Hastelloy C22 Over C276
Both Hastelloy C22 (UNS N06022) and Hastelloy C276 (UNS N10276) are Ni-Cr-Mo alloys with broad corrosion resistance across oxidising and reducing media. The critical difference is chromium content: C22 contains 20–22.5% Cr versus C276’s 14.5–16.5%, and adds tungsten (2.5–3.5%) alongside molybdenum (12.5–14.5%). This higher Cr content gives C22 distinctly superior resistance to pitting, crevice corrosion, and stress corrosion cracking in oxidising chloride environments — the failure modes most relevant to flanged pressure joints.
In practical terms: C22 stud bolts are specified when the service environment contains oxidising acids (HNO₃, HClO₄), mixed acid streams, wet chlorine, hypochlorite, or FGD (flue gas desulphurisation) scrubber service — where C276 may exhibit localised pitting under operating conditions. C22 also demonstrates better resistance to ferric and cupric chlorides. For purely reducing acid environments (HCl, H₂SO₄ reducing), our Hastelloy B3 stud bolts remain the specification of choice.
Akbar Fasteners Pvt. Ltd. machines C22 stud bolts from ASTM B574 certified UNS N06022 bar stock, XRF PMI-verifies every lot against the mill certificate before production, and dispatches with NABL-accredited mechanical test reports, MTC, and COC. Matched C22 heavy hex nuts from same heat on request.
| Element | Min % | Max % | Typical |
|---|---|---|---|
| Nickel (Ni) | Balance | — | ~57% |
| Chromium (Cr) | 20.0 | 22.5 | ~22% |
| Molybdenum (Mo) | 12.5 | 14.5 | ~13% |
| Tungsten (W) | 2.5 | 3.5 | ~3% |
| Iron (Fe) | 2.0 | 6.0 | ~4% |
| Cobalt (Co) | — | 2.5 | — |
| Manganese (Mn) | — | 0.5 | — |
| Carbon (C) | — | 0.010 | — |
| Silicon (Si) | — | 0.08 | — |
| Vanadium (V) | — | 0.35 | — |
Hastelloy C22 Stud Bolt Configurations
All configurations machined from ASTM B574 solution-annealed UNS N06022 bar. Custom end lengths, thread engagement per ASME PCC-1, and non-standard diameters on request.
Fully Threaded Stud
Thread runs the complete length — standard for ASME B16.5 raised-face and ring-joint flanged pressure joints. Both ends receive a C22 heavy hex nut. Class 150–2500. The most common C22 stud bolt configuration for FGD scrubber nozzles and mixed acid process flanges.
Equal-End Stud Bolt
Threaded ends of equal length with a plain centre shank — confirms correct nut engagement length during tightening. Essential for high-integrity flanged joints in FGD ductwork and wet scrubber systems where over- or under-engagement is a safety issue. M12–M100.
Unequal-End Stud
One end screws permanently into a tapped nozzle or valve body; the nut is applied to the other. Used in oxidising chloride service chemical reactor nozzles and agitated vessel covers where permanent thread engagement on one side is required. Thread engagement per ASME B1.1.
FGD Scrubber Studs
Hastelloy C22 is the primary stud bolt alloy for FGD (flue gas desulphurisation) absorber tower nozzles and ductwork flanges — where wet SO₂ gas combined with oxidising chloride creates the mixed-acid environment that makes C276 insufficient and C22 mandatory. Class 300–600, M20–M64.
Long Shank / Thermal
Extended plain shank for thermal expansion accommodation in high-temperature chemical process flanges and agitated reactor covers. C22’s thermal stability up to 650°C makes it suitable for elevated temperature oxidising acid service where stress corrosion cracking resistance is required.
Custom / Non-Standard
Left-hand thread, inch UNC/UNF, non-standard diameters, lengths to 3,000mm, and drawing-specific configurations. C22 stud bolts for pharmaceutical reactors, nuclear plant water treatment, and bespoke chemical plant projects. Send drawing to sales@akbarfasteners.in.
ASME B16.5 C22 Stud Bolt Lengths — Class 150 to 2500
Standard lengths per ASME B16.5 / ASME B18.31.2 including two heavy hex nuts. All in mm. Compare with our Hastelloy B3 stud bolt dimension table for reducing acid service. Custom lengths to 3,000mm.
| Dia. (M) | Thread Pitch | Class 150 (mm) | Class 300 (mm) | Class 600 (mm) | Class 900 (mm) | Class 1500 (mm) | Class 2500 (mm) |
|---|---|---|---|---|---|---|---|
| METRIC — UNS N06022 · ASTM B574 · SOLUTION ANNEALED | |||||||
| M12 | 1.75 mm | 90 | 100 | 115 | 125 | 140 | — |
| M16 | 2.0 mm | 100 | 110 | 125 | 140 | 160 | — |
| M20 | 2.5 mm | 110 | 125 | 140 | 160 | 185 | 215 |
| M24 | 3.0 mm | 125 | 140 | 160 | 180 | 210 | 245 |
| M30 | 3.5 mm | 145 | 165 | 190 | 215 | 255 | 300 |
| M36 | 4.0 mm | 170 | 195 | 225 | 260 | 305 | 360 |
| M42 | 4.5 mm | 195 | 225 | 265 | 305 | 355 | 420 |
| M48 | 5.0 mm | 220 | 260 | 300 | 345 | 400 | 475 |
| M56 | 5.5 mm | — | 290 | 340 | 390 | 455 | 545 |
| M64 | 6.0 mm | — | 325 | 380 | 440 | 515 | 615 |
| M72 – M100 | 6.0 mm | — | — | Custom | Custom | Custom | — |
* Confirmed on order against flange dimensions. Inch UNC/UNF available. Custom to 3,000mm — sales@akbarfasteners.in
Standards We Manufacture & Test To
Same quality system as our Hastelloy B3 stud bolts and complete exotic alloy range. Full heat traceability from mill certificate to dispatch.
Industry Applications
Hastelloy C22 is the specification where oxidising chloride environments, mixed acids, wet chlorine, or FGD service make C276 insufficient — applications demanding the highest pitting and crevice resistance available.
FGD Scrubbers
wet SO₂ flange joints
Chemical Processing
oxidising chloride service
Oil & Gas
offshore Cl⁻ environments
Desalination Plants
concentration stage
Pulp & Paper
hypochlorite service
Pharmaceutical
CIP system flanges
Offshore Platforms
subsea manifold flanges
Waste Treatment
scrubber nozzle joints
Complete Documentation Package
Heat & Lot Traceable
Conformance
100% Lots Verified
Tensile · Hardness
TÜV · BV · Lloyds
Compare Hastelloy Grades for Your Service
Choose the right Hastelloy grade — C22 for oxidising chloride/FGD, B3 for reducing acids, C276 for broad mixed-media service.
Hastelloy B3 Stud Bolts
For HCl and reducing acid service where C22 is not specified. Near-zero corrosion in HCl at all concentrations. ASME B16.5 Class 150–2500. M12–M100.
View Page →ASTM B574 Hastelloy Fasteners
Full Hastelloy range under one ASTM standard. Grade selection matrix — C276 vs C22 vs B3 corrosion environments. All product forms available.
View All Grades →Hastelloy Fasteners — India
Complete Hastelloy manufacturer page — six grades as bolts, studs, nuts, washers. Grade selection guidance and export to 50+ countries from Mumbai.
View Range →Hastelloy B3 Fasteners
Full B3 range — hex bolts, hex nuts, washers, socket screws. Product selector tabs with dimensional data. Complete matched assembly from one source.
View Page →Need Hastelloy C22
Stud Bolts Now?
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