Hastelloy C276
Stud Bolts
UNS N10276
Hastelloy C276 — When Broadest Coverage Matters
Hastelloy C276 (UNS N10276) contains the highest molybdenum content in the commercial Ni-Cr-Mo alloy family — 15–17% Mo — combined with 14.5–16.5% Cr and 3–4.5% W. This composition makes C276 the engineer’s first choice when the process environment is mixed, uncertain, or capable of switching between oxidising and reducing states. Unlike alloys optimised for a specific acid type, C276 performs excellently across both oxidising acids (HNO₃, hypochlorite), reducing acids (H₂SO₄, HCl at lower concentrations), organic acids, and chlorinated solvents simultaneously.
The key difference in stud bolt application: specify C276 when the flanged joint connects equipment handling mixed or multiple acid streams, chlorinated process fluids, or when the corrosive conditions are not precisely defined. For pure oxidising chloride service (FGD scrubbers), our Hastelloy C22 stud bolts provide superior pitting resistance. For purely reducing HCl at all concentrations, our Hastelloy B3 stud bolts are the specification of choice. C276 covers the broad middle ground where neither is definitively specified.
Akbar Fasteners Pvt. Ltd. machines C276 stud bolts from ASTM B574 certified UNS N10276 solution-annealed bar. Every lot PMI-verified against the MTC before production. Matched C276 heavy hex nuts from same certified heat supplied as sets for complete ASME B16.5 flange assemblies with single documentation.
| Element | Min % | Max % | Typical |
|---|---|---|---|
| Nickel (Ni) | Balance | — | ~57% |
| Molybdenum (Mo) | 15.0 | 17.0 | ~16% |
| Chromium (Cr) | 14.5 | 16.5 | ~15.5% |
| Tungsten (W) | 3.0 | 4.5 | ~4% |
| Iron (Fe) | 4.0 | 7.0 | ~5.5% |
| Cobalt (Co) | — | 2.5 | — |
| Manganese (Mn) | — | 1.0 | — |
| Carbon (C) | — | 0.010 | — |
| Silicon (Si) | — | 0.08 | — |
| Vanadium (V) | — | 0.35 | — |
Hastelloy C276 Stud Bolt Configurations
All configurations machined from ASTM B574 solution-annealed UNS N10276 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 C276 heavy hex nut. Class 150–2500. The most common C276 stud bolt configuration for chemical plant mixed-media service and multi-fluid process plants.
Equal-End Stud Bolt
Threaded ends of equal length with a plain centre shank — confirms correct nut engagement during tightening. Essential for high-integrity ASME B16.5 flanged joints in chemical reactors and agitated vessel nozzles in mixed acid service where over- or under-engagement is a safety issue.
Unequal-End Stud
One end screws permanently into a tapped nozzle or equipment body; the nut is applied to the other. Common in chemical process equipment with tapped nozzle connections, agitated vessel covers, and heat exchanger tube-side headers in mixed corrosive service. Thread engagement per ASME B1.1.
Medium-High Pressure Stud
Standard stud bolt sets for Class 600 and Class 900–1500 flanged joints in high-pressure chemical reactor nozzles, high-pressure heat exchanger covers, and offshore chemical injection systems where C276’s broad corrosion resistance in mixed media is combined with Class 900+ pressure ratings. M24–M100.
Long Shank / Custom
Extended plain shank for accommodation of thick insulation between flanges, thermal expansion, or large face-to-face gasket distance. Lengths to 3,000mm. Used in chemical plant expansion joints, insulated process flanges in mixed acid service, and offshore pipeline joints in corrosive service.
Inch UNC/UNF & Custom
Inch thread UNC/UNF for US projects, left-hand thread, non-standard diameters, and drawing-specific configurations. C276 stud bolts for pharmaceutical multipurpose reactors handling variable acid media, and bespoke offshore chemical plant. Send drawing to sales@akbarfasteners.in.
ASME B16.5 C276 Stud Bolt Lengths — Class 150 to 2500
Standard lengths per ASME B16.5 / ASME B18.31.2 including two C276 heavy hex nuts. All in mm. Compare with our Hastelloy C22 stud bolt table for oxidising chloride / FGD 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 N10276 · 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 ASTM B574 Hastelloy fastener range. Full heat traceability from mill certificate to dispatch.
Industry Applications
Hastelloy C276 stud bolts are specified when mixed acid media, chlorinated solvents, or uncertain corrosive conditions require the broadest single-alloy protection in ASME B16.5 flanged joints.
Chemical Processing
multipurpose plant flanges
Oil & Gas
offshore mixed media
Offshore Platforms
seawater + acid service
Marine & Naval
chemical dosing systems
Pulp & Paper
mixed acid recovery joints
Desalination
brine circuit flanges
Pharmaceutical
CIP system flanges
Waste Treatment
scrubber nozzle joints
Complete Documentation Package
Heat & Lot Traceable
Conformance
100% Lots Verified
Tensile · Hardness
TÜV · BV · Lloyds
Select the Right Hastelloy Grade
C276 for mixed media, C22 for oxidising chloride, B3 for reducing HCl — choose the grade matched to your service environment. All from one ISO 9001:2015 certified source.
Hastelloy B3 Stud Bolts
For reducing HCl and H₂SO₄ service where B3 outperforms C276. Near-zero corrosion in HCl at all concentrations. Class 150–2500, M12–M100 to 3,000mm.
View Page →Hastelloy C22 Stud Bolts
For FGD scrubbers and oxidising chloride service where C22’s higher Cr gives superior pitting resistance over C276. Class 150–2500, M12–M100.
View Page →Hastelloy C276 Threaded Rods
Full-length C276 threaded rods for chemical plant hanger systems, equipment tie-rods, and long-reach applications. M6–M100, lengths to 3,000mm.
View Page →ASTM B574 Hastelloy Fasteners
Full Hastelloy range — C276, C22, C4, B3, B2 as stud bolts, hex bolts, hex nuts, washers. Grade selection matrix for your corrosion environment.
View All Grades →Need Hastelloy C276
Stud Bolts Now?
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