Hastelloy B3
Fasteners
Hastelloy B3 Hex Bolts
Hex bolts manufactured from ASTM B335 certified UNS N10675 bar. Available in full thread (DIN 933) and partial thread (DIN 931). The 28–33% Mo content delivers near-zero corrosion in boiling concentrated HCl — the mandatory specification for HCl synthesis reactor closure bolts where 316L would fail within hours.
Standard and heavy hex head configurations. Matching B3 heavy hex nuts available as a set. PMI-verified, NABL tested, full MTC supplied.
| Spec | Details |
|---|---|
| Material | UNS N10675 / B3 |
| Size Range | M6 — M100 |
| Standard | DIN 931 · DIN 933 · ISO 4014 |
| Thread | Metric · UNC · UNF |
| UTS | ≥ 760 MPa |
| 0.2% YS | ≥ 345 MPa |
| Elongation | ≥ 40% |
| Hardness | ≤ 241 HBW |
Hastelloy B3 Stud Bolts
Fully threaded and double-end stud bolts for ASME B16.5 flanged pressure joints in reducing acid service. Matching B3 heavy hex nuts supplied as a certified set. Equal and unequal end lengths available. Thread engagement per ASME PCC-1.
Critical for HCl plant nozzle joints, acid reactor pressure boundaries, and pharmaceutical autoclave assemblies where any foreign material contamination must be eliminated.
| Spec | Details |
|---|---|
| Material | UNS N10675 / B3 |
| Size Range | M12 — M100 |
| Max Length | 3,000 mm |
| Standard | ASME B16.5 · DIN 976 · ASTM B335 |
| Config | Fully Threaded · Equal · Unequal End |
| Press. Class | ASME 150# to 2500# |
| Nuts | Heavy Hex — matched UNS N10675 |
| Docs | MTC · COC · PMI · NABL |
Hastelloy B3 Hex Nuts
Standard hex nuts (DIN 934) and heavy hex nuts (ASME B18.2.2) in Hastelloy B3. Manufactured from the same certified UNS N10675 mill heat as our bolts — ensuring identical composition for galvanic compatibility in acid service. Coupling nuts (DIN 6334) available for rod-to-rod joints.
| Spec | Details |
|---|---|
| Material | UNS N10675 / B3 |
| Size Range | M6 — M100 |
| Standard | DIN 934 · ASME B18.2.2 · DIN 6334 |
| Types | Std Hex · Heavy Hex · Coupling |
| Thread | Metric · UNC · UNF |
| Hardness | ≤ 241 HBW |
| Docs | MTC · COC · PMI · NABL |
Hastelloy B3 Socket Cap Screws
ISO 4762 socket head cap screws in B3 for instrumentation, valve bodies, pump casings, and enclosed equipment. The hex socket drive provides 3× stronger engagement than a hex head — critical where bolt faces may partially corrode between maintenance cycles.
| Spec | Details |
|---|---|
| Material | UNS N10675 / B3 |
| Size Range | M3 — M36 |
| Standard | ISO 4762 · DIN 912 · DIN 6912 |
| Drive | Hex Socket · Torx on request |
| Head | Socket Head · Button · Flat Head |
| UTS | ≥ 760 MPa |
Hastelloy B3 Threaded Rods
Fully threaded rods (DIN 975 / DIN 976) in Hastelloy B3, cut from ASTM B335 bar in lengths up to 3,000 mm. Thread rolled or cut. Used for reactor agitator shaft seals, expansion joints, and structural hanger rods in acid plant ductwork.
| Spec | Details |
|---|---|
| Material | UNS N10675 / B3 |
| Diameter | M6 — M100 |
| Max Length | 3,000 mm |
| Standard | DIN 975 · DIN 976 · ASTM B335 |
| Thread Form | Metric · UNC · UNF · BSW |
| Ends | Square · Chamfered · Custom |
Hastelloy B3 Set Screws
Fully threaded grub/set screws in Hastelloy B3 for shaft locking, flow control plugs, and position adjustment in acid service equipment. Specified in pharma hydrogenation where corrosion product contamination is unacceptable, and HCl environments where 316L grubs fail within one cycle.
| Spec | Details |
|---|---|
| Material | UNS N10675 / B3 |
| Size Range | M3 — M24 |
| Standard | DIN 913–916 · ISO 4026–4029 |
| Point Styles | Flat · Cone · Dog · Cup · Oval |
| Drive | Hex Socket (Allen) |
Why B3 Outperforms Every Reducing-Acid Alternative
Hastelloy B3 (UNS N10675) is a nickel-molybdenum-chromium-tungsten alloy — the third generation of the B-series. Its 28–33% molybdenum content is the highest of any commercially available nickel alloy, delivering near-zero corrosion in non-oxidising acids at any concentration up to boiling point.
The key B3 improvement over B2: controlled additions of Cr (1–3%), Fe (1–3%) and W (2.5–4%) eliminate the ordered Ni₃Mo intermetallic phase that caused knife-line attack in B2 during slow cooling. For fastener manufacture — where thick hex bolt heads spend extended time in the sensitisation range — this is a critical advantage that B2 cannot offer.
For procurement engineers: B3 eliminates the strict post-weld cooling-rate requirements of B2, making it significantly more manufacturable as bolts and stud bolts without risk of grain-boundary precipitation or sensitisation cracking in service.
| 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 | <0.08% |
| Carbon (C) | — | 0.01 | <0.01% |
| Phosphorus (P) | — | 0.030 | — |
| Sulfur (S) | — | 0.030 | — |
Full Hastelloy B3 Fastener Specifications
All products from ASTM B335 / B333 certified UNS N10675. Mechanical properties per ASTM A370. Custom sizes on request.
| Product | Standard | Size Range | UNS | UTS | 0.2% YS | Hardness |
|---|---|---|---|---|---|---|
| BOLTS | ||||||
| Hex Bolts — Full Thread | DIN 933 / ISO 4017 | M6–M100 | N10675 | ≥760 MPa | ≥345 MPa | ≤241 HBW |
| Hex Bolts — Part. Thread | DIN 931 / ISO 4014 | M6–M100 | N10675 | ≥760 MPa | ≥345 MPa | ≤241 HBW |
| Heavy Hex Bolts | ASME B18.2.3.6M | M12–M100 | N10675 | ≥760 MPa | ≥345 MPa | ≤241 HBW |
| STUD BOLTS | ||||||
| Fully Threaded Stud Bolt | ASME B16.5 / DIN 976 | M12–M100 | N10675 | ≥760 MPa | ≥345 MPa | ≤241 HBW |
| Double-End Stud Bolt | DIN 939 / DIN 938 | M6–M100 | N10675 | ≥760 MPa | ≥345 MPa | ≤241 HBW |
| NUTS | ||||||
| Hex Nuts | DIN 934 / ISO 4032 | M6–M100 | N10675 | — | — | ≤241 HBW |
| Heavy Hex Nuts | ASME B18.2.2 | M12–M100 | N10675 | — | — | ≤241 HBW |
| Coupling Nuts | DIN 6334 | M6–M48 | N10675 | — | — | ≤241 HBW |
| SCREWS & RODS | ||||||
| Socket Cap Screws | ISO 4762 / DIN 912 | M3–M36 | N10675 | ≥760 MPa | ≥345 MPa | ≤241 HBW |
| Set Screws (Grub) | DIN 913–916 | M3–M24 | N10675 | — | — | ≤241 HBW |
| Threaded Rods | DIN 975 / DIN 976 | M6–M100, ≤3000mm | N10675 | ≥760 MPa | ≥345 MPa | ≤241 HBW |
| Eye Bolts / U-Bolts | DIN 580 / Custom | M10–M64 | N10675 | ≥760 MPa | ≥345 MPa | ≤241 HBW |
* Custom sizes, special configurations and non-standard thread forms available — send drawing to sales@akbarfasteners.in
Standards We Manufacture & Test To
Full documentation traceable from raw material heat number to finished fastener dispatch. Every order ships complete.
Industries That Specify Hastelloy B3
B3’s near-zero HCl corrosion rate is irreplaceable in these environments where SS, Duplex, and even C276 are insufficient.
HCl Synthesis Plants
vent & drain assemblies
Chemical Reactors
agitator shaft seals
Pharma Hydrogenation
high-pressure vessels
Pulp & Paper
digester nozzles
Steel Mill Pickling
pickling line fasteners
Petrochemical
acid catalyst service
Semiconductor Fabs
wet etch stations
Fertiliser Plants
fluoride environments
Complete Documentation Package
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Conformance
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Complete Hastelloy & Nickel Alloy Range
Same heat, same documentation — every component for your assembly. Or explore alternatives for different environments.
Hastelloy B3 Washers
Plain, spring and lock washers in B3 to DIN 125 / ISO 7089. M5–M100. Same heat documentation.
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