Property Class 12.9 Steel T-Slot Nuts are supplied to DIN 508. The grade provides requires plating or black-oxide protection and is magnetic; the practical service range is commonly limited to approx. +300 °C; confirm against the coating and the load. Property data, grade comparison and the full size table follow.
Why Choose Property Class 12.9 Steel for T-Slot Nuts
The highest common strength class, for high-load machine assembly. For t-slot nuts, this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 12.9 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
| Corrosion characteristic | Requires plating or black-oxide protection |
Corrosion Behavior in Service
Carbon and alloy steel t-slot nuts require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.
Galvanic & Galling Considerations
For t-slot 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.
Sizes of T-Slot Nuts Available in Property Class 12.9 Steel
| Thread size | T-slot width (mm) | Nut width b (mm) | Total height h (mm) | Key height h1 (mm) | Hook width e (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M5 | 6 | 8.0 | 8.0 | 4.5 | 6.4 | DIN 508 / GN505 |
| M6 | 8 | 10.0 | 10.0 | 5.5 | 8.4 | DIN 508 / GN505 |
| M8 | 10 | 12.0 | 12.0 | 7.0 | 10.4 | DIN 508 / GN505 |
| M8 | 12 | 14.0 | 12.0 | 7.0 | 12.4 | DIN 508 / GN505 |
| M10 | 12 | 14.0 | 14.0 | 8.0 | 12.4 | DIN 508 / GN505 |
| M10 | 14 | 16.0 | 14.0 | 8.0 | 14.4 | DIN 508 / GN505 |
| M12 | 14 | 16.0 | 17.0 | 10.0 | 14.4 | DIN 508 / GN505 |
| M12 | 18 | 20.0 | 17.0 | 10.0 | 18.4 | DIN 508 / GN505 |
| M16 | 18 | 20.0 | 20.0 | 12.0 | 18.4 | DIN 508 / GN505 |
| M16 | 22 | 25.0 | 20.0 | 12.0 | 22.4 | DIN 508 / GN505 |
| M20 | 22 | 25.0 | 25.0 | 15.0 | 22.4 | DIN 508 / GN505 |
| M20 | 28 | 32.0 | 25.0 | 15.0 | 28.4 | DIN 508 / GN505 |
| M24 | 28 | 32.0 | 30.0 | 18.0 | 28.4 | DIN 508 / GN505 |


