Property Class 8.8 Steel Vented Vacuum Screws are supplied to ISO 4762. The grade provides requires plating (zinc) for corrosion protection and is magnetic; the practical service range is commonly limited to approx. +300 °C; confirm against the coating and the load. Property data, grade comparison and the full size table follow.
Why Choose Property Class 8.8 Steel for Vented Vacuum Screws
The workhorse medium-carbon alloy class for structural joints. For vented vacuum screws, this matters when requires plating (zinc) for corrosion protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 8.8 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
| Corrosion characteristic | Requires plating (zinc) for corrosion protection |
Corrosion Behavior in Service
Carbon and alloy steel vented vacuum 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 vented vacuum 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 Vented Vacuum Screws Available in Property Class 8.8 Steel
| Thread size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Hex socket s (mm) | Vent hole diameter (mm) | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|
| M3 | 0.5 | 5.5 | 3.0 | 2.5 | 0.8 | 6~30 | ISO 4762 vented |
| M4 | 0.7 | 7.0 | 4.0 | 3 | 1.0 | 8~40 | ISO 4762 vented |
| M5 | 0.8 | 8.5 | 5.0 | 4 | 1.2 | 10~50 | ISO 4762 vented |
| M6 | 1.0 | 10.0 | 6.0 | 5 | 1.5 | 10~60 | ISO 4762 vented |
| M8 | 1.25 | 13.0 | 8.0 | 6 | 2.0 | 12~80 | ISO 4762 vented |
| M10 | 1.5 | 16.0 | 10.0 | 8 | 2.5 | 16~80 | ISO 4762 vented |
