Property Class 12.9 Steel Shear Nuts (Breakaway Security Nuts) are supplied to our own published dimensions — this is a trade-series article rather than one covered by a dimensional standard, so confirm the figures against the part you are replacing. 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.
Why Choose Property Class 12.9 Steel for Shear Nuts (Breakaway Security Nuts)
The highest common strength class, for high-load machine assembly. For shear nuts (breakaway security 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 |
Galvanic & Galling Considerations
For shear nuts (breakaway security 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 Shear Nuts (Breakaway Security Nuts), class 8.8 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 Shear Nuts (Breakaway Security Nuts) Available in Property Class 12.9 Steel
| Thread size | Cone diameter (mm) | Nut height m (mm) | Drive hex across flats (mm) | Nominal shear torque (Nm) | Material | Finish | Removal |
|---|---|---|---|---|---|---|---|
| M6 | 14.0 | 10.0 | 10 | 10 | Steel | Zinc plated | Cut / split |
| M8 | 17.0 | 12.0 | 13 | 22 | Steel | Zinc plated | Cut / split |
| M10 | 20.0 | 14.0 | 17 | 45 | Steel | Zinc plated | Cut / split |
| M12 | 24.0 | 16.0 | 19 | 75 | Steel | Hot-dip galv | Cut / split |
| M16 | 30.0 | 20.0 | 24 | 180 | Steel | Hot-dip galv | Cut / split |
Dimensions are independent of the material: every size above is available in Property Class 12.9 Steel.
Custom manufacturing · Made to drawing
Need this nut in a grade that is not listed?
Grade 12 9 Steel is one of the grades the catalog describes. Thread, height, across-flats, property class, locking feature and flange form can all be varied, including thread sizes the standard series does not run to. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
