Grade 12.9 Steel Cheese Head Screws are stocked to ISO 7048 / DIN 7985. 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 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 |
Corrosion Behavior in Service
Carbon and alloy steel cheese head screws 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 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.
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) |