Hastelloy B3
Bolts
Hastelloy B3 — Third-Generation Ni-Mo Alloy
Hastelloy B3 (UNS N10675) is the most advanced nickel-molybdenum alloy commercially available. The controlled additions of chromium (1–3%), iron (1–3%), and tungsten (2.5–4%) over the B2 composition eliminate ordered Ni₄Mo intermetallic phase formation during slow cooling — eliminating the sensitisation failure mode that affected thick bolt sections in B and B2.
For hex bolt and stud bolt applications, this thermal stability improvement is decisive. A B3 bolt machined from a 60mm bar retains the same corrosion performance as thin sheet, whereas B2 may exhibit knife-line attack at grain boundaries. This makes Hastelloy B3 the preferred bolting alloy for high-integrity HCl and reducing acid flanged assemblies.
With the highest molybdenum content of any commercially produced alloy, B3 outperforms SS 316L in HCl by orders of magnitude, and exceeds Hastelloy C276 in pure reducing acid environments where chloride-induced pitting is not the primary concern.
| 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 | — |
| Silicon (Si) | — | 0.10 | <0.1% |
| Carbon (C) | — | 0.01 | <0.01% |
| Phosphorus (P) | — | 0.030 | — |
| Sulfur (S) | — | 0.030 | — |
Hastelloy B3 Bolt Types
All configurations manufactured from certified UNS N10675 bar stock with full dimensional inspection and material documentation.
Hex Head Bolts
DIN 931 partial thread and DIN 933 full thread. ISO 4014/4017. M6–M160, lengths to 3000mm. Standard and heavy hex.
Stud Bolts
Fully threaded for ASME B16.5/B16.47 flanged joints. Double-end and full-thread. Inch UNC/UNF and metric.
Eye Bolts
DIN 580 lifting eye bolts for corrosive chemical environments. Working load per ISO 3266. M8–M64.
U-Bolts
Round and square bend U-bolts for HCl pipe clamp applications. Custom leg length and thread length.
Double-End Studs
Equal and unequal leg studs for tap-end and through-hole fastening. DIN 938/939 or custom.
Standard Sizes — Hex Bolts (DIN 931 / ISO 4014)
All dimensions per DIN 931 / ISO 4014. Custom lengths, heavy hex, ASME stud bolt patterns available. All dimensions in mm.
| Bolt Size | Thread Pitch | AF (mm) | Head Height k | Shank d₂ | Std Length (mm) | Wt (kg/pc) |
|---|---|---|---|---|---|---|
| M6 | 1.00 | 10 | 4.0 | 6.0 | 20–80 | 0.0052 |
| M8 | 1.25 | 13 | 5.3 | 8.0 | 20–100 | 0.0117 |
| M10 | 1.50 | 17 | 6.4 | 10.0 | 25–120 | 0.0225 |
| M12 | 1.75 | 19 | 7.5 | 12.0 | 30–150 | 0.0395 |
| M16 | 2.00 | 24 | 10.0 | 16.0 | 40–200 | 0.0982 |
| M20 | 2.50 | 30 | 12.5 | 20.0 | 50–250 | 0.1916 |
| M24 | 3.00 | 36 | 15.0 | 24.0 | 60–300 | 0.3295 |
| M30 | 3.50 | 46 | 18.7 | 30.0 | 80–400 | 0.6728 |
| M36 | 4.00 | 55 | 22.5 | 36.0 | 100–500 | 1.1664 |
| M42 | 4.50 | 65 | 26.0 | 42.0 | 120–600 | 1.9310 |
| M48 | 5.00 | 75 | 30.0 | 48.0 | 150–700 | 2.9380 |
| M56 | 5.50 | 85 | 35.0 | 56.0 | 150–800 | 4.6200 |
| M64 | 6.00 | 95 | 40.0 | 64.0 | 200–900 | 6.9100 |
| M72 | 6.00 | 105 | 45.0 | 72.0 | 200–1000 | 9.8700 |
| M80 | 6.00 | 115 | 50.0 | 80.0 | 200–1200 | 13.620 |
| M100 | 6.00 | 145 | 63.0 | 100.0 | 300–2000 | 26.670 |
| M120 | 6.00 | 170 | 75.0 | 120.0 | 300–2500 | 46.100 |
| M160 | 6.00 | 225 | 100.0 | 160.0 | 400–3000 | 110.40 |
* Custom lengths to 3000mm, left-hand thread, heavy hex, ASME stud bolt patterns available — send drawing to sales@akbarfasteners.in
Material Performance
Properties of Hastelloy B3 in the annealed condition per ASTM B335. Results from NABL-accredited laboratory reports.
| Property | Value |
|---|---|
| Ultimate Tensile Strength | ≥760 MPa |
| 0.2% Proof Stress | ≥345 MPa |
| Elongation | ≥40% |
| Hardness — Max. | 241 HB / 100 HRB |
| Max. Service Temperature | 550°C (1020°F) |
| Min. Service Temperature | –196°C (cryogenic) |
| Density | 9.22 g/cm³ |
| Melting Range | 1370–1418°C |
| Thermal Conductivity | 11.1 W/m·K @ 100°C |
| Elastic Modulus | 214 GPa |
| Coeff. of Expansion | 10.0 µm/m·°C |
| Electrical Resistivity | 137 µΩ·cm |
Standards We Manufacture To
Every Hastelloy B3 bolt manufactured, tested, and certified to the applicable standard. Full documentation with every order.
Where Hastelloy B3 Bolts Are Specified
B3’s molybdenum content makes it the standard specification for the most severe reducing acid environments worldwide.
HCl Synthesis Plants
absorber towers
Chemical Processing
reducing acid units
Pharmaceutical
API synthesis
Pulp & Paper
bleaching sequences
Oil & Gas Refining
sour crude desalters
Fertiliser Plants
fluoride service
Semiconductor
HCl gas systems
Specialty Chemicals
reducing acid processes
How Every B3 Bolt Is Made & Certified
Six documented quality stages from material receipt to dispatch — ISO 9001:2015 certified.
Certified Mill Material Receipt
Hastelloy B3 bar sourced with EN 10204 3.1 MTCs. Every heat logged with full chemical analysis against UNS N10675 limits before entering production.
PMI Verification — XRF Testing
100% incoming PMI using portable XRF. Nickel and molybdenum confirmed against certificate. Non-conforming lots quarantined and returned — no exceptions.
Forging & CNC Machining
Hot forging of hex heads, CNC turning of shank to DIN 931/ISO 4014. First-article inspection issued before full production run.
Thread Rolling & Gauge Inspection
Cold thread rolling per ISO 724. Thread form checked with calibrated go/no-go gauges at 100% final inspection.
NABL Lab Mechanical Testing
Tensile, proof load, hardness per ASTM A370 at NABL-accredited laboratory. Reports traceable to specific heat and lot.
Final Documentation & Dispatch
MTC, COC, PMI report, dimensional report assembled per order. TPI by TÜV, BV or client body co-ordinated if required.
Full Documentation Package
Heat & Lot Traceable
ID Report
Conformance
Tensile · Hardness
TÜV · BV · Lloyds
Matching Hastelloy B3 Components
Same alloy, same heat, same certification — source your complete assembly from one supplier.
Hastelloy B3 Nuts
Heavy hex and standard hex nuts. DIN 934 / ASME B18.2.2. M6–M100. Matching material and certification.
Enquire →Hastelloy B3 Washers
Plain, spring and lock washers. DIN 125 / ISO 7089. M5–M100. Full MTC, PMI, COC.
View Page →Hastelloy B3 Stud Bolt Sets
Complete stud bolt and nut sets for ASME B16.5 flanged joint assembly. All pressure classes.
Enquire →Hastelloy C276 Bolts
For oxidising + reducing environments where B3 is not suitable. Same size range and documentation.
Enquire →Specify Size & Standard.
We’ll Certify It.
Size, type, quantity, standard, and documentation requirements. Akbar Fasteners Pvt. Ltd. responds within 24 hours with pricing, lead time, and full documentation list.