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Product Overview
Hastelloy B2 studs are nickel-molybdenum alloy fasteners manufactured from UNS N10665 bar stock conforming to ASTM B335. The alloy’s exceptionally high molybdenum content (26-30%) delivers outstanding resistance to hydrochloric acid at all concentrations and temperatures, including boiling HCl – a performance level unmatched by any stainless steel or standard nickel alloy fastener.
Hastelloy B2 studs are specified in chemical process industries where reducing acid environments, hydrogen chloride gas, and sulfuric acid at moderate concentrations demand a fastener material that will not corrode under flange bolt loads. The alloy conforms to NACE MR0175 hardness limits and is widely used in reactor closures, distillation column flanges, and acid storage vessel nozzle connections worldwide.
| Material | Hastelloy B2 |
| UNS Number | N10665 |
| DIN Number | 2.4617 |
| Material Standard | ASTM B335 |
| Stud Standard (Metric) | DIN 938 / DIN 939 / ISO 4032 |
| Stud Standard (Inch) | ASME B18.31.2 / ASME B16.5 |
| Thread Form | ISO Metric / UNC / UNF |
| Diameter Range | M6-M100 / ¼"-4" |
| Tensile Strength | 760 MPa (110 ksi) min |
| Yield Strength | 350 MPa (51 ksi) min |
| Hardness | Max 35 HRC / 241 HB |
Complete the Fastener Set
Technical Data
| Size (M) | Pitch (mm) | Shank Dia (mm) | Thread Length (mm) | Min L (mm) | Max L (mm) |
|---|---|---|---|---|---|
| M6 | 1.0 | 6.0 | 18 | 20 | 200 |
| M8 | 1.25 | 8.0 | 22 | 25 | 250 |
| M10 | 1.5 | 10.0 | 26 | 30 | 300 |
| M12 | 1.75 | 12.0 | 30 | 35 | 400 |
| M16 | 2.0 | 16.0 | 38 | 45 | 500 |
| M20 | 2.5 | 20.0 | 46 | 55 | 600 |
| M24 | 3.0 | 24.0 | 54 | 65 | 700 |
| M30 | 3.5 | 30.0 | 66 | 80 | 800 |
| M36 | 4.0 | 36.0 | 78 | 100 | 1000 |
| M42 | 4.5 | 42.0 | 90 | 120 | 1200 |
| M48 | 5.0 | 48.0 | 102 | 140 | 1500 |
| M56 | 5.5 | 56.0 | 118 | 160 | 1800 |
| M64 | 6.0 | 64.0 | 134 | 180 | 2000 |
| M72 | 6.0 | 72.0 | 150 | 200 | 2000 |
| M80 | 6.0 | 80.0 | 166 | 220 | 2500 |
| M100 | 6.0 | 100.0 | 200 | 250 | 3000 |
| Standard | Covers | Thread |
|---|---|---|
| DIN 938 | Studs, one-end engagement | Metric |
| DIN 939 | Studs, both-end engagement | Metric |
| ISO 4032 | Hex nuts for studs | Metric |
| ASME B18.31.2 | Continuous thread studs | UNC/UNF |
| ASME B16.5 | Stud bolts for flanges | UNC |
| MSS SP-75 | Stud bolts, high-pressure | UNC |
| ASME B16.47 | Large diameter flange studs | UNC |
| Material Standard | Requirement |
|---|---|
| ASTM B335 | Bar/rod - UNS N10665 |
| ASTM F468 | Fastener mechanical properties |
| NACE MR0175 | Sour service =35 HRC |
| EN 10204 3.1 | Mill test certificate |
| EN 10204 3.2 | TPI-witnessed MTC |
Material Chemistry
| Element | Composition (%) |
|---|---|
| Nickel (Ni) | Balance (min 65%) |
| Molybdenum (Mo) | 26.0-30.0% |
| Iron (Fe) | 2.0% max |
| Chromium (Cr) | 1.0% max |
| Carbon (C) | 0.02% max |
| Manganese (Mn) | 1.0% max |
| Silicon (Si) | 0.10% max |
| Cobalt (Co) | 1.0% max |
| Phosphorus (P) | 0.04% max |
| Sulfur (S) | 0.03% max |
Fastener Performance
| Stud Size | Dry (Nm) | Lubricated (Nm) | Clamp Load (kN) |
|---|---|---|---|
| M12 | 82 | 66 | 30 |
| M16 | 198 | 158 | 72 |
| M20 | 395 | 316 | 115 |
| M24 | 685 | 548 | 167 |
| M30 | 1370 | 1096 | 265 |
| M36 | 2380 | 1904 | 385 |
| M42 | 3800 | 3040 | 530 |
| M48 | 5640 | 4512 | 698 |
Industry Applications
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