Property Class 12.9 Steel Thin Castle Nuts (DIN 937) combine the dimensional form of DIN 937 with the material properties of grade ISO 898-1 property class 12.9: requires plating or black-oxide protection, magnetic, service range commonly limited to approx. +300 °C; confirm against the coating and the load. This page summarizes the grade data, its corrosion behavior in service, the comparable grades, and the sizes supplied.
Why Choose Property Class 12.9 Steel for Thin Castle Nuts (DIN 937)
The highest common strength class, for high-load machine assembly. For thin castle nuts (din 937), 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 thin castle nuts (din 937) 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 Thin Castle Nuts (DIN 937), 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 Thin Castle Nuts (DIN 937) Available in Property Class 12.9 Steel
| Thread size | Pitch (mm) | Width across flats s (mm) | Total height m (mm) | Height vs DIN 935 | Slot width n (mm) | Split pin size | Reference standard |
|---|---|---|---|---|---|---|---|
| M10 | 1.5 | 17.0 | 8.0 | approx. 70% | 2.8 | 2.5 x 30 | DIN 937 |
| M12 | 1.75 | 19.0 | 10.0 | approx. 71% | 3.5 | 3.2 x 36 | DIN 937 |
| M16 | 2.0 | 24.0 | 13.0 | approx. 76% | 4.5 | 4 x 40 | DIN 937 |
| M20 | 2.5 | 30.0 | 16.0 | approx. 80% | 4.5 | 4 x 50 | DIN 937 |
| M24 | 3.0 | 36.0 | 19.0 | approx. 79% | 5.5 | 5 x 63 | DIN 937 |
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.
