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Product Overview
ASTM A193 Grade B8M nuts are austenitic stainless steel fasteners manufactured from Type 316/316L stainless steel, designated as UNS S31600/S31603. These nuts are solution-annealed and strain-hardened to achieve enhanced mechanical properties, making them ideal for high-pressure, high-temperature bolted joints in corrosive environments. B8M nuts are widely specified for use with B8M bolts and studs in petrochemical, power generation, and marine applications where superior resistance to chlorides and acids is required.
All B8M nuts are produced to ASTM A194 Grade 8M or 8MLN standards for compatible mechanical and corrosion performance. They are available in both heavy hex and regular hex patterns, with full traceability and certification per EN 10204 3.1 or 3.2.
| Material | Stainless Steel 316/316L |
| UNS Number | S31600 / S31603 |
| DIN Number | 1.4401 / 1.4404 |
| Material Standard | ASTM A193 Grade B8M |
| Nut Standard (Metric) | DIN 934 / ISO 4032 |
| Nut Standard (Inch) | ASME B18.2.2 |
| Thread Form | ISO Metric / UNC / UNF |
| Size Range | M6-M100 / ¼"-4" |
| Proof Load | 600 MPa (87 ksi) min |
| Tensile Strength | 515 MPa (75 ksi) min |
| Hardness | Max 223 HB / 95 HRB |
Complete the Fastener Set
Technical Data
| Size (M) | Pitch (mm) | A/F (mm) | Height (mm) |
|---|---|---|---|
| M6 | 1.0 | 10 | 5 |
| M8 | 1.25 | 13 | 6.5 |
| M10 | 1.5 | 17 | 8 |
| M12 | 1.75 | 19 | 10 |
| M16 | 2.0 | 24 | 13 |
| M20 | 2.5 | 30 | 16 |
| M24 | 3.0 | 36 | 19 |
| M30 | 3.5 | 46 | 24 |
| M36 | 4.0 | 55 | 29 |
| M42 | 4.5 | 65 | 34 |
| M48 | 5.0 | 75 | 38 |
| M56 | 5.5 | 85 | 45 |
| M64 | 6.0 | 95 | 51 |
| M72 | 6.0 | 105 | 58 |
| M80 | 6.0 | 115 | 65 |
| M100 | 6.0 | 145 | 80 |
| Standard | Covers | Thread |
|---|---|---|
| DIN 934 | Hex nuts | Metric |
| ISO 4032 | Hex nuts | Metric |
| ASME B18.2.2 | Hex & heavy hex nuts | UNC/UNF |
| ASTM A194 8M | Heavy hex nuts | UNC/UNF |
| ASTM A194 8MLN | Low carbon nuts | UNC/UNF |
| Material Standard | Requirement |
|---|---|
| ASTM A193 B8M | Bar/forging - S31600/S31603 |
| ASTM A194 8M/8MLN | Nut mechanical |
| EN 10204 3.1 | Mill test certificate |
| EN 10204 3.2 | TPI-witnessed MTC |
Material Chemistry
| Element | Composition (%) |
|---|---|
| Chromium (Cr) | 16.0-18.0 |
| Nickel (Ni) | 10.0-14.0 |
| Molybdenum (Mo) | 2.00-3.00 |
| Manganese (Mn) | 2.00 max |
| Silicon (Si) | 1.00 max |
| Carbon (C) | 0.08 max (B8M), 0.03 max (B8MLN) |
| Phosphorus (P) | 0.045 max |
| Sulfur (S) | 0.030 max |
| Nitrogen (N) | 0.10 max |
| Iron (Fe) | Balance |
Fastener Performance
| Nut Size | Proof Load (kN) | Recommended Torque (Nm) |
|---|---|---|
| M12 | 84 | 70 |
| M16 | 146 | 170 |
| M20 | 229 | 340 |
| M24 | 332 | 590 |
| M30 | 520 | 1200 |
| M36 | 753 | 2100 |
| M42 | 1040 | 3200 |
| M48 | 1400 | 4500 |
Industry Applications
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