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Product Overview
ASTM A193 Grade B8 bolts are high-performance stainless steel fasteners manufactured from austenitic stainless steel, specifically Type 304 (UNS S30400), and are solution-annealed and carbide solution treated to ensure optimal corrosion resistance and mechanical strength. These bolts are widely specified for pressure vessels, piping, valves, and flanged connections in chemical, petrochemical, and power generation industries due to their excellent resistance to oxidation and general corrosion.
Grade B8 bolts are available in both Class 1 (annealed) and Class 2 (strain-hardened) conditions, offering a balance of ductility and strength. They are the industry standard for bolting in ASME B16.5 flanges, heat exchangers, and process equipment where reliable performance in elevated temperatures and corrosive environments is required.
| Material | Stainless Steel 304 (AISI 304) |
| UNS Number | S30400 |
| DIN Number | 1.4301 |
| Material Standard | ASTM A193 |
| Bolt Standard (Metric) | DIN 931 / DIN 933 / ISO 4014 |
| Bolt Standard (Inch) | ASME B18.2.1 |
| Thread Form | ISO Metric / UNC / UNF |
| Diameter Range | M6-M100 / ¼"-4" |
| Tensile Strength | 515 MPa (Class 1) / 860 MPa (Class 2) |
| Yield Strength | 205 MPa (Class 1) / 600 MPa (Class 2) |
| Hardness | Max 223 HBW (Class 1) / 321 HBW (Class 2) |
Complete the Fastener Set
Technical Data
| Size (M) | Pitch (mm) | A/F (mm) | Head Ht (mm) | Min L (mm) | Max L (mm) |
|---|---|---|---|---|---|
| M6 | 1.0 | 10 | 4.0 | 10 | 200 |
| M8 | 1.25 | 13 | 5.3 | 12 | 250 |
| M10 | 1.5 | 17 | 6.4 | 16 | 300 |
| M12 | 1.75 | 19 | 7.5 | 20 | 400 |
| M16 | 2.0 | 24 | 10.0 | 25 | 500 |
| M20 | 2.5 | 30 | 12.5 | 30 | 600 |
| M24 | 3.0 | 36 | 15.0 | 40 | 600 |
| M30 | 3.5 | 46 | 18.7 | 50 | 800 |
| M36 | 4.0 | 55 | 22.5 | 60 | 1000 |
| M42 | 4.5 | 65 | 26.0 | 80 | 1000 |
| M48 | 5.0 | 75 | 30.0 | 100 | 1200 |
| M56 | 5.5 | 85 | 35.0 | 120 | 1500 |
| M64 | 6.0 | 95 | 40.0 | 140 | 2000 |
| M72 | 6.0 | 105 | 45.0 | 160 | 2000 |
| M80 | 6.0 | 115 | 50.0 | 180 | 2500 |
| M100 | 6.0 | 145 | 63.0 | 200 | 3000 |
| Standard | Covers | Thread |
|---|---|---|
| DIN 931 | Hex bolts, partial thread | Metric |
| DIN 933 | Hex bolts, full thread | Metric |
| ISO 4014 | Hex head screws, partial | Metric |
| ISO 4017 | Hex head screws, full | Metric |
| ASME B18.2.1 | Hex & heavy hex bolts | UNC/UNF |
| ASME B16.5 | Stud bolts for flanges | UNC |
| MSS SP-75 | Stud bolts, high-pressure | UNC |
| Material Standard | Requirement |
|---|---|
| ASTM A193 | Bolting - S30400 |
| ASTM A194 | Companion nuts |
| EN 10204 3.1 | Mill test certificate |
| EN 10204 3.2 | TPI-witnessed MTC |
Material Chemistry
| Element | Composition (%) |
|---|---|
| Chromium (Cr) | 18.0-20.0% |
| Nickel (Ni) | 8.0-11.0% |
| Carbon (C) | 0.08% max |
| Manganese (Mn) | 2.00% max |
| Silicon (Si) | 1.00% max |
| Phosphorus (P) | 0.045% max |
| Sulfur (S) | 0.030% max |
| Nitrogen (N) | 0.10% max |
| Iron (Fe) | Balance |
Fastener Performance
| Bolt Size | Dry (Nm) | Lubricated (Nm) | Clamp Load (kN) |
|---|---|---|---|
| M12 | 70 | 56 | 28 |
| M16 | 170 | 136 | 57 |
| M20 | 340 | 272 | 89 |
| M24 | 590 | 472 | 128 |
| M30 | 1200 | 960 | 206 |
| M36 | 2100 | 1680 | 298 |
| M42 | 3300 | 2640 | 420 |
| M48 | 4800 | 3840 | 570 |
Industry Applications
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