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Product Overview
Metric Grade 8.8 washers are high-strength carbon steel flat washers manufactured to complement Grade 8.8 bolts and fasteners in structural and mechanical assemblies. These washers are produced from medium carbon steel, quenched and tempered to achieve a minimum tensile strength of 800 MPa and a yield strength of 640 MPa, as specified in ISO 898-1 and EN 14399-6 standards.
Grade 8.8 washers are designed to distribute load, prevent surface damage, and reduce the risk of bolt loosening under dynamic or vibrational loads. They are widely used in construction, automotive, heavy machinery, and general engineering applications where reliable clamping force and consistent preload are critical.
| Material | Medium Carbon Steel, Grade 8.8 |
| Standard | ISO 7089 / ISO 7090 / DIN 125 / EN 14399-6 |
| Hardness | 200-300 HV |
| Tensile Strength | 800 MPa min |
| Yield Strength | 640 MPa min |
| Finish | Plain, Zinc Plated, Hot Dip Galvanized |
| Diameter Range | M6-M64 |
| Thickness Range | 1.6-8.0 mm |
| Application | Structural, Automotive, Machinery |
Complete the Fastener Set
Technical Data
| Size (M) | Inner Dia (mm) | Outer 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 |
| Standard | Covers | Thread |
|---|---|---|
| ISO 7089 | Plain washers | Metric |
| ISO 7090 | Chamfered washers | Metric |
| DIN 125 | Flat washers | Metric |
| EN 14399-6 | Structural washers | Metric |
| ASME B18.22.1 | Plain washers (inch) | UNC/UNF |
| Material Standard | Requirement |
|---|---|
| ISO 898-1 | Mechanical properties |
| EN 14399-6 | Structural bolting assemblies |
| EN 10204 3.1 | Mill test certificate |
| ISO 4042 | Coating requirements |
Material Chemistry
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.25-0.55 |
| Manganese (Mn) | 0.50-1.65 |
| Phosphorus (P) | 0.035 max |
| Sulfur (S) | 0.035 max |
| Silicon (Si) | 0.10-0.50 |
| Chromium (Cr) | 0.30 max |
| Nickel (Ni) | 0.30 max |
| Copper (Cu) | 0.25 max |
| Molybdenum (Mo) | 0.08 max |
Fastener Performance
| Bolt Size | Recommended Washer OD (mm) | Recommended Washer Thickness (mm) |
|---|---|---|
| M8 | 16 | 1.6 |
| M10 | 20 | 2.0 |
| M12 | 24 | 2.5 |
| M16 | 30 | 3.0 |
| M20 | 37 | 3.0 |
| M24 | 44 | 4.0 |
| M30 | 56 | 4.0 |
| M36 | 66 | 5.0 |
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