Grade 8.8 Steel Hex Bolts, Grade C combine the dimensional form of ISO 4016 with the material properties of grade class 8.8: requires plating (zinc) for corrosion protection, magnetic, service range up to approx. +300 °C. This page summarizes the grade data, its corrosion behavior in service, the comparable grades, and the sizes supplied.
Why Choose Grade 8.8 Steel for Hex Bolts, Grade C
The workhorse medium-carbon alloy grade for structural joints. For hex bolts, grade c, this matters when requires plating (zinc) for corrosion protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | class 8.8 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | up to approx. +300 °C |
| Corrosion characteristic | Requires plating (zinc) for corrosion protection |
Galvanic & Galling Considerations
For hex bolts, grade c in steel, the dominant compatibility issue is hydrogen embrittlement at high property classes (10.9 and above) when electroplated. Plating must be followed by an appropriate baking treatment, or a non-electroplated finish (mechanical zinc, zinc flake) should be substituted.
Comparable Grades
For Hex Bolts, Grade C, class 10.9 or 12.9 is the comparable strength step. Move up when the joint preload approaches the proof load of the current class; move down when the joint is over-specified. For corrosion-critical service, switch to stainless A2 or A4.
Sizes of Hex Bolts, Grade C Available in Grade 8.8 Steel
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e min (mm) | Head height k (mm) | Product grade | Reference standard |
|---|---|---|---|---|---|---|
| M5 | 0.8 | 8.0 | 8.63 | 3.35 | Grade C | ISO 4016 / DIN 601 |
| M6 | 1.0 | 10.0 | 10.89 | 4.15 | Grade C | ISO 4016 / DIN 601 |
| M8 | 1.25 | 13.0 | 14.2 | 5.45 | Grade C | ISO 4016 / DIN 601 |
| M10 | 1.5 | 17.0 | 18.72 | 6.58 | Grade C | ISO 4016 / DIN 601 |
| M12 | 1.75 | 19.0 | 20.88 | 7.68 | Grade C | ISO 4016 / DIN 601 |
| M14 | 2.0 | 22.0 | 24.49 | 9.25 | Grade C | ISO 4016 / DIN 601 |
| M16 | 2.0 | 24.0 | 26.75 | 10.18 | Grade C | ISO 4016 / DIN 601 |
| M18 | 2.5 | 27.0 | 29.56 | 11.72 | Grade C | ISO 4016 / DIN 601 |
| M20 | 2.5 | 30.0 | 33.53 | 12.72 | Grade C | ISO 4016 / DIN 601 |
| M22 | 2.5 | 32.0 | 35.72 | 14.5 | Grade C | ISO 4016 / DIN 601 |
| M24 | 3.0 | 36.0 | 39.55 | 15.35 | Grade C | ISO 4016 / DIN 601 |
| M27 | 3.0 | 41.0 | 45.2 | 17.92 | Grade C | ISO 4016 / DIN 601 |
| M30 | 3.5 | 46.0 | 50.85 | 19.75 | Grade C | ISO 4016 / DIN 601 |
| M36 | 4.0 | 55.0 | 60.79 | 23.35 | Grade C | ISO 4016 / DIN 601 |
| M42 | 4.5 | 65.0 | 71.3 | 27.05 | Grade C | ISO 4016 / DIN 601 |
| M48 | 5.0 | 75.0 | 82.6 | 31.07 | Grade C | ISO 4016 / DIN 601 |