Property Class 12.9 Steel Socket Nuts (Hex Drive, Round Body) 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 Socket Nuts (Hex Drive, Round Body)
The highest common strength class, for high-load machine assembly. For socket nuts (hex drive, round body), 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 socket nuts (hex drive, round body) 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 Socket Nuts (Hex Drive, Round Body), 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 Socket Nuts (Hex Drive, Round Body) Available in Property Class 12.9 Steel
| Thread size | Outer diameter (mm) | Nut height m (mm) | Hex socket s (mm) | Socket depth (mm) | Material | Finish | Note |
|---|---|---|---|---|---|---|---|
| M4 | 8.0 | 8.0 | 4.0 | 3.5 | Alloy steel | Black oxide | Fits 8 mm bore |
| M5 | 10.0 | 10.0 | 5.0 | 4.5 | Alloy steel | Black oxide | Fits 10 mm bore |
| M6 | 12.0 | 12.0 | 6.0 | 5.5 | Alloy steel | Black oxide | Fits 12 mm bore |
| M8 | 15.0 | 15.0 | 8.0 | 7.0 | Alloy steel | Black oxide | Fits 15 mm bore |
| M10 | 18.0 | 18.0 | 10.0 | 9.0 | Alloy steel | Black oxide | Fits 18 mm bore |
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 size is the obvious variable and rarely the interesting one — height for clearance, across-flats for the tool already in the cell, and the locking feature for the vibration actually present. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
