Hastelloy B3
Stud Bolts
Why Hastelloy B3 for Stud Bolts
Hastelloy B3 (UNS N10675 / DIN 2.4600) is the most advanced Ni-Mo alloy available for reducing acid service. Its predecessor B2 suffered from precipitation of Ni₄Mo ordered phases at grain boundaries during slow cooling, drastically reducing corrosion resistance in the sensitised zone. B3 eliminates this entirely through precisely controlled additions of chromium, iron, and tungsten — making it safe to use in as-manufactured stud bolt condition without post-fabrication solution annealing.
For stud bolts specifically, B3’s advantage over B2 is decisive. Stud bolts pass through flanges, are often tightened hot, cooled slowly, and retorqued — exactly the thermal cycling that exposes B2’s grain-boundary weakness. B3 maintains its corrosion resistance through all of this, making it the specified choice for HCl alkylation units, hydrobromic acid service, and phosphoric acid reactors where flange integrity is critical.
All Akbar Fasteners Pvt. Ltd. Hastelloy B3 stud bolts are manufactured from ASTM B335 certified bar stock, PMI-verified on receipt, and supplied with full mill traceability, dimensional certification, and NABL mechanical test reports.
| Element | % Min | % Max | Typical |
|---|---|---|---|
| Nickel (Ni) | Balance | Balance | ~65% |
| Molybdenum (Mo) | 27.0 | 32.0 | ~30% |
| Chromium (Cr) | 1.0 | 3.0 | ~1.5% |
| Iron (Fe) | 1.0 | 3.0 | ~2.0% |
| Tungsten (W) | 2.5 | 4.0 | ~3.0% |
| Cobalt (Co) | — | 3.0 | — |
| Manganese (Mn) | — | 3.0 | — |
| Silicon (Si) | — | 0.10 | <0.1% |
| Carbon (C) | — | 0.01 | <0.01% |
| Phosphorus (P) | — | 0.03 | — |
| Sulfur (S) | — | 0.03 | — |
Hastelloy B3 Stud Bolt Types
All types manufactured in Hastelloy B3 with complete dimensional and material documentation.
Fully Threaded Studs
Threaded end to end. Standard for ASME B16.5 pressure piping. B3 equivalent of A193 B7M for reducing acid flange service. Most common configuration.
Double-End Stud Bolts
Threaded at both ends with plain shank at centre. Equal thread length both sides. Used in ASME B16.5 flange assemblies requiring symmetrical nut engagement.
Tap-End Stud Bolts
Short threaded tap end screws into a tapped hole; longer nut end takes a hex nut. Used for equipment flanges bolted to valve bodies, pump housings and pressure vessels.
Threaded Rods / All-Stud
Continuous threaded rod in custom cut lengths. Multiple nuts engageable along the entire length. Used in heat exchanger tie-rods and custom flanged connections.
Standard Sizes — ASME B16.5 Stud Bolts
Lengths and diameters per ASME B16.5. Three pressure classes shown. Custom lengths and special engagement available. All dimensions in mm.
| Pipe Size | Stud Dia. | Length (mm) | No. of Studs | Thread Pitch | Nut Height |
|---|---|---|---|---|---|
| ½″ (DN 15) | M12 | 80 | 4 | 1.75 | 10 mm |
| ¾″ (DN 20) | M12 | 90 | 4 | 1.75 | 10 mm |
| 1″ (DN 25) | M16 | 100 | 4 | 2.0 | 13 mm |
| 1½″ (DN 40) | M16 | 110 | 4 | 2.0 | 13 mm |
| 2″ (DN 50) | M16 | 120 | 4 | 2.0 | 13 mm |
| 2½″ (DN 65) | M20 | 130 | 4 | 2.5 | 16 mm |
| 3″ (DN 80) | M20 | 140 | 4 | 2.5 | 16 mm |
| 4″ (DN 100) | M20 | 150 | 8 | 2.5 | 16 mm |
| 6″ (DN 150) | M24 | 170 | 8 | 3.0 | 19 mm |
| 8″ (DN 200) | M24 | 185 | 8 | 3.0 | 19 mm |
| 10″ (DN 250) | M27 | 200 | 12 | 3.0 | 22 mm |
| 12″ (DN 300) | M27 | 215 | 12 | 3.0 | 22 mm |
| 14″ (DN 350) | M30 | 240 | 12 | 3.5 | 24 mm |
| 16″ (DN 400) | M30 | 255 | 16 | 3.5 | 24 mm |
| 18″ (DN 450) | M36 | 280 | 16 | 4.0 | 29 mm |
| 20″ (DN 500) | M36 | 295 | 20 | 4.0 | 29 mm |
| 24″ (DN 600) | M42 | 330 | 20 | 4.5 | 34 mm |
| Pipe Size | Stud Dia. | Length (mm) | No. of Studs | Thread Pitch | Nut Height |
|---|---|---|---|---|---|
| ½″ (DN 15) | M16 | 100 | 4 | 2.0 | 13 mm |
| ¾″ (DN 20) | M16 | 110 | 4 | 2.0 | 13 mm |
| 1″ (DN 25) | M16 | 120 | 4 | 2.0 | 13 mm |
| 1½″ (DN 40) | M20 | 135 | 4 | 2.5 | 16 mm |
| 2″ (DN 50) | M20 | 145 | 8 | 2.5 | 16 mm |
| 2½″ (DN 65) | M24 | 165 | 8 | 3.0 | 19 mm |
| 3″ (DN 80) | M24 | 175 | 8 | 3.0 | 19 mm |
| 4″ (DN 100) | M27 | 195 | 8 | 3.0 | 22 mm |
| 6″ (DN 150) | M30 | 225 | 12 | 3.5 | 24 mm |
| 8″ (DN 200) | M36 | 265 | 12 | 4.0 | 29 mm |
| 10″ (DN 250) | M39 | 295 | 16 | 4.0 | 31 mm |
| 12″ (DN 300) | M42 | 320 | 16 | 4.5 | 34 mm |
| 14″ (DN 350) | M45 | 355 | 20 | 4.5 | 36 mm |
| 16″ (DN 400) | M52 | 390 | 20 | 5.0 | 42 mm |
| 18″ (DN 450) | M52 | 415 | 24 | 5.0 | 42 mm |
| 20″ (DN 500) | M56 | 445 | 24 | 5.5 | 45 mm |
| 24″ (DN 600) | M64 | 510 | 24 | 6.0 | 51 mm |
| Pipe Size | Stud Dia. | Length (mm) | No. of Studs | Thread Pitch | Nut Height |
|---|---|---|---|---|---|
| ½″ (DN 15) | M16 | 115 | 4 | 2.0 | 13 mm |
| ¾″ (DN 20) | M20 | 130 | 4 | 2.5 | 16 mm |
| 1″ (DN 25) | M20 | 140 | 4 | 2.5 | 16 mm |
| 1½″ (DN 40) | M24 | 165 | 4 | 3.0 | 19 mm |
| 2″ (DN 50) | M27 | 185 | 8 | 3.0 | 22 mm |
| 3″ (DN 80) | M30 | 215 | 8 | 3.5 | 24 mm |
| 4″ (DN 100) | M36 | 255 | 8 | 4.0 | 29 mm |
| 6″ (DN 150) | M42 | 305 | 12 | 4.5 | 34 mm |
| 8″ (DN 200) | M48 | 360 | 12 | 5.0 | 38 mm |
| 10″ (DN 250) | M56 | 415 | 16 | 5.5 | 45 mm |
| 12″ (DN 300) | M64 | 475 | 20 | 6.0 | 51 mm |
| 14″ (DN 350) | M72 | 525 | 20 | 6.0 | 58 mm |
| 16″ (DN 400) | M80 | 580 | 20 | 6.0 | 64 mm |
| 18″ (DN 450) | M90 | 640 | 20 | 6.0 | 72 mm |
| 20″ (DN 500) | M90 | 680 | 24 | 6.0 | 72 mm |
| 24″ (DN 600) | M100 | 760 | 24 | 6.0 | 80 mm |
* Custom lengths, non-standard pitches and special engagement requirements manufactured on request — send specification to sales@akbarfasteners.in
Standards We Manufacture To
Every Hastelloy B3 stud bolt is manufactured, tested, and certified to the applicable international standard. Full documentation supplied with every order.
Where Hastelloy B3 Studs Are Specified
B3’s unmatched HCl and reducing acid resistance makes it the first-choice specification in environments that destroy SS and other Ni alloys.
HCl Alkylation Units
in HCl process streams
Chemical Reactors
process equipment
Pharmaceutical
flanged connections
Pulp & Paper
pressure vessels
Offshore / Subsea
wellhead flanges
Fertiliser Plants
HF service studs
Semiconductor
handling equipment
Hydrobromic Acid
reaction vessels
Complete Documentation Package
Heat & Lot Traceable
Conformance
XRF Verified
Tensile · Hardness
TÜV · BV · Lloyds
Related Hastelloy B3 Products
Source your complete flanged joint assembly from one certified supplier — same alloy, same heat, same documentation.
Hastelloy B3 Nuts
Heavy hex nuts to match B3 stud bolts. ASME B18.2.2. M6–M100. Matching material certificate and heat number available.
Enquire →Hastelloy B3 Washers
Plain flat and spring washers in Hastelloy B3. DIN 125 / ISO 7089. M6–M100. PMI report and MTC supplied.
View Product →Hastelloy B3 Hex Bolts
DIN 931/933 hex bolts in Hastelloy B3 for applications requiring hex head access. M6–M72. Full MTC.
Enquire →Hastelloy C276 Studs
For mixed oxidising/reducing environments. C276 where both acid types are present or chloride pitting is a concern.
Enquire →Need Hastelloy B3
Stud Bolts Fast?
Tell us flange class, pipe size, and quantity — or send your stud bolt schedule. We respond within 24 hours with pricing, lead time, and documentation list.