Grade 12.9 Steel Woodruff Keys are stocked to DIN 6888. The grade provides requires plating or black-oxide protection and is magnetic; the practical service range is up to approx. +300 °C. Property data, grade comparison and the full size table follow.
Why Choose Grade 12.9 Steel for Woodruff Keys
The highest common strength class, for high-load machine assembly. For woodruff keys, this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | class 12.9 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | up to approx. +300 °C |
| Corrosion characteristic | Requires plating or black-oxide protection |
Corrosion Behavior in Service
Carbon and alloy steel woodruff keys 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 woodruff keys 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 Woodruff Keys Available in Grade 12.9 Steel
| Key width b (mm) | Disc diameter d (mm) | Key height h (mm) | Chord length l (mm) | Shaft groove depth t1 (mm) | Hub groove depth t2 (mm) | Reference standard |
|---|---|---|---|---|---|---|
| 1.0 | 4 | 1.4 | 3.7 | 1.0 | 0.6 | DIN 6888 / ISO 3912 |
| 1.5 | 4 | 1.4 | 3.7 | 1.0 | 0.6 | DIN 6888 / ISO 3912 |
| 2.0 | 5 | 1.8 | 4.7 | 1.4 | 0.6 | DIN 6888 / ISO 3912 |
| 2.0 | 6 | 2.6 | 5.7 | 2.0 | 0.8 | DIN 6888 / ISO 3912 |
| 2.5 | 7 | 3.0 | 6.8 | 2.3 | 1.0 | DIN 6888 / ISO 3912 |
| 3.0 | 7 | 3.0 | 6.8 | 2.3 | 1.0 | DIN 6888 / ISO 3912 |
| 3.0 | 9 | 4.0 | 8.8 | 3.2 | 1.0 | DIN 6888 / ISO 3912 |
| 3.0 | 10 | 4.5 | 9.8 | 3.5 | 1.2 | DIN 6888 / ISO 3912 |
| 4.0 | 9 | 4.0 | 8.8 | 3.2 | 1.0 | DIN 6888 / ISO 3912 |
| 4.0 | 10 | 4.5 | 9.8 | 3.5 | 1.2 | DIN 6888 / ISO 3912 |
| 4.0 | 13 | 6.0 | 12.7 | 5.0 | 1.4 | DIN 6888 / ISO 3912 |
| 5.0 | 10 | 4.5 | 9.8 | 3.5 | 1.2 | DIN 6888 / ISO 3912 |
| 5.0 | 13 | 6.0 | 12.7 | 5.0 | 1.4 | DIN 6888 / ISO 3912 |
| 5.0 | 16 | 7.5 | 15.7 | 6.3 | 1.4 | DIN 6888 / ISO 3912 |
| 6.0 | 13 | 6.0 | 12.7 | 5.0 | 1.4 | DIN 6888 / ISO 3912 |
| 6.0 | 16 | 7.5 | 15.7 | 6.3 | 1.4 | DIN 6888 / ISO 3912 |
| 6.0 | 19 | 9.0 | 18.6 | 7.5 | 1.8 | DIN 6888 / ISO 3912 |
| 8.0 | 19 | 9.0 | 18.6 | 7.5 | 1.8 | DIN 6888 / ISO 3912 |
| 8.0 | 22 | 11.0 | 21.6 | 9.3 | 1.8 | DIN 6888 / ISO 3912 |
| 10.0 | 22 | 11.0 | 21.6 | 9.3 | 1.8 | DIN 6888 / ISO 3912 |
| 10.0 | 25 | 13.0 | 24.5 | 11.0 | 2.3 | DIN 6888 / ISO 3912 |