Specifying Cheese Head Screws in Grade 12.9 Steel pairs the dimensional form of Cheese Head Screws (ISO 7048 / DIN 7985) with the engineering properties of Grade 12.9 Steel. This page explains when to choose the grade, how it behaves in service, and which grades to compare it against.
Why Choose Grade 12.9 Steel for Cheese Head Screws
The highest common strength class, for high-load machine assembly. For cheese head screws, 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 |
Galvanic & Galling Considerations
For cheese head screws 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 Cheese Head Screws, 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 Cheese Head Screws Available in Grade 12.9 Steel
| Size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Cross recess | Reference standard |
|---|---|---|---|---|---|
| M1.6 | 0.35 | 3.0 | 1.6 | PH0 | ISO 7048 / DIN 7985 (cross) / ISO 1207 (slotted) |
| M2 | 0.4 | 3.8 | 2.0 | PH1 | ISO 7048 / DIN 7985 (cross) / ISO 1207 (slotted) |
| M2.5 | 0.45 | 5.0 | 2.5 | PH1 | ISO 7048 / DIN 7985 (cross) / ISO 1207 (slotted) |
| M3 | 0.5 | 5.5 | 3.0 | PH1 | ISO 7048 / DIN 7985 (cross) / ISO 1207 (slotted) |
| M3.5 | 0.6 | 6.0 | 3.5 | PH2 | ISO 7048 / DIN 7985 (cross) / ISO 1207 (slotted) |
| M4 | 0.7 | 7.0 | 4.0 | PH2 | ISO 7048 / DIN 7985 (cross) / ISO 1207 (slotted) |
| M5 | 0.8 | 8.5 | 5.0 | PH2 | ISO 7048 / DIN 7985 (cross) / ISO 1207 (slotted) |
| M6 | 1.0 | 10.0 | 6.0 | PH3 | ISO 7048 / DIN 7985 (cross) / ISO 1207 (slotted) |
| M8 | 1.25 | 13.0 | 8.0 | PH3 | ISO 7048 / DIN 7985 (cross) / ISO 1207 (slotted) |
| M10 | 1.5 | 16.0 | 10.0 | PH4 | ISO 7048 / DIN 7985 (cross) / ISO 1207 (slotted) |