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Product Overview
ASTM A307 Grade B washers are carbon steel flat washers manufactured to meet the requirements of ASTM A307 for use with Grade B bolts and studs in piping flanges and pressure vessel connections. These washers are designed to provide a smooth, load-distributing bearing surface under the head of a bolt or nut, preventing damage to the connected material and ensuring uniform clamping force. ASTM A307 Grade B washers are commonly specified for moderate-strength, non-critical bolted joints in structural, piping, and general industrial applications where high strength or corrosion resistance is not required.
Produced from low-carbon steel, these washers are hot-rolled or cold-formed and supplied in plain, zinc-plated, or hot-dip galvanized finishes. They are compatible with both inch and metric fasteners and are widely used in conjunction with ASTM A307 Grade B bolts and nuts for flange assemblies, structural steelwork, and equipment mounting.
| Material | Carbon Steel |
| Grade | ASTM A307 Grade B |
| Material Standard | ASTM A307 |
| Washer Standard (Inch) | ASME B18.22.1 |
| Washer Standard (Metric) | DIN 125 / ISO 7089 |
| Finish | Plain, Zinc Plated, Hot-Dip Galvanized |
| Hardness | Max 85 HRB |
| Diameter Range | 1/4"-4" (M6-M100) |
| Thickness Range | 1.6-8.0 mm |
| Tensile Strength (Bolt) | 414 MPa (60 ksi) min |
| Yield Strength (Bolt) | 207 MPa (30 ksi) min |
Complete the Fastener Set
Technical Data
| Nominal Size | Inside Dia. (in) | Outside Dia. (in) | Thickness (in) |
|---|---|---|---|
| 1/4" | 0.281 | 0.625 | 0.065 |
| 3/8" | 0.406 | 0.875 | 0.083 |
| 1/2" | 0.531 | 1.062 | 0.109 |
| 5/8" | 0.656 | 1.312 | 0.134 |
| 3/4" | 0.812 | 1.500 | 0.148 |
| 1" | 1.062 | 2.000 | 0.188 |
| 1-1/4" | 1.375 | 2.500 | 0.219 |
| 1-1/2" | 1.625 | 3.000 | 0.250 |
| 2" | 2.062 | 3.750 | 0.312 |
| 2-1/2" | 2.562 | 4.500 | 0.375 |
| 3" | 3.062 | 5.250 | 0.438 |
| 4" | 4.062 | 7.000 | 0.562 |
| Size (M) | Inside Dia. (mm) | Outside Dia. (mm) | Thickness (mm) |
|---|---|---|---|
| M6 | 6.4 | 12 | 1.6 |
| M8 | 8.4 | 16 | 1.6 |
| M10 | 10.5 | 20 | 2.0 |
| M12 | 13.0 | 24 | 2.5 |
| M16 | 17.0 | 30 | 3.0 |
| M20 | 21.0 | 37 | 3.0 |
| M24 | 25.0 | 44 | 4.0 |
| M30 | 31.0 | 56 | 4.0 |
| M36 | 37.0 | 66 | 5.0 |
| M42 | 43.0 | 78 | 6.0 |
| M48 | 49.0 | 92 | 6.0 |
| M56 | 57.0 | 105 | 8.0 |
| M64 | 65.0 | 115 | 8.0 |
| M72 | 73.0 | 130 | 8.0 |
| M80 | 81.0 | 140 | 8.0 |
| M100 | 101.0 | 180 | 8.0 |
| Standard | Covers | Thread |
|---|---|---|
| ASME B18.22.1 | Plain washers (inch) | Inch |
| DIN 125 | Flat washers (metric) | Metric |
| ISO 7089 | Flat washers (metric) | Metric |
| DIN 126 | Heavy duty washers | Metric |
| BS 4320 | Form A/B/C/D washers | Metric/Inch |
| Material Standard | Requirement |
|---|---|
| ASTM A307 | Carbon steel, Grade B |
| ASTM F844 | General purpose washers |
| EN 10204 3.1 | Mill test certificate |
| EN 10204 3.2 | TPI-witnessed MTC |
Material Chemistry
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.27 max |
| Manganese (Mn) | 0.60-0.90 |
| Phosphorus (P) | 0.04 max |
| Sulfur (S) | 0.15 max |
| Iron (Fe) | Balance |
Fastener Performance
| Washer Size | Recommended Bolt Torque (Nm) | Compatible Bolt Size |
|---|---|---|
| 1/4" | 12 | 1/4"-20 UNC |
| 3/8" | 40 | 3/8"-16 UNC |
| 1/2" | 80 | 1/2"-13 UNC |
| 5/8" | 160 | 5/8"-11 UNC |
| 3/4" | 280 | 3/4"-10 UNC |
| 1" | 570 | 1"-8 UNC |
| 1-1/4" | 1020 | 1-1/4"-7 UNC |
| 1-1/2" | 1700 | 1-1/2"-6 UNC |
Industry Applications
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