Property Class 8.8 Steel (ISO 898-1 property class 8.8) is the workhorse medium-carbon alloy class for structural joints. When hexagon weld nuts are specified in this grade, the dimensions remain per DIN 929; the material determines corrosion behavior (requires plating (zinc) for corrosion protection) and the service temperature range (commonly limited to approx. +300 °C; confirm against the coating and the load). Both are covered below with the size table.
Why Choose Property Class 8.8 Steel for Hexagon Weld Nuts
The workhorse medium-carbon alloy class for structural joints. For hexagon weld nuts, this matters when requires plating (zinc) for corrosion protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 8.8 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
| Corrosion characteristic | Requires plating (zinc) for corrosion protection |
Galvanic & Galling Considerations
For hexagon weld nuts 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 Hexagon Weld Nuts, 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 Hexagon Weld Nuts Available in Property Class 8.8 Steel
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e (mm) | Nut height m (mm) | Pilot diameter d2 (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M3 | 0.5 | 7.5 | 8.15 | 3 | 4.5 | DIN 929 |
| M4 | 0.7 | 9 | 9.83 | 3.5 | 6 | DIN 929 |
| M5 | 0.8 | 10 | 10.95 | 4 | 7 | DIN 929 |
| M6 | 1.0 | 11 | 12.02 | 5 | 8 | DIN 929 |
| M8 | 1.25 | 14 | 15.38 | 6.5 | 10.5 | DIN 929 |
| M10 | 1.5 | 17 | 18.74 | 8 | 12.5 | DIN 929 |
| M12 | 1.75 | 19 | 20.91 | 10 | 14.8 | DIN 929 |
| M14 | 2.0 | 22 | 24.27 | 11 | 16.8 | DIN 929 |
| M16 | 2.0 | 24 | 26.51 | 13 | 18.8 | DIN 929 |
