Property Class 8.8 Steel Pin-in-Torx Security Screws combine the dimensional form of ISO 14583 with the material properties of grade ISO 898-1 property class 8.8: requires plating (zinc) for corrosion 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 8.8 Steel for Pin-in-Torx Security Screws
The workhorse medium-carbon alloy class for structural joints. For pin-in-torx security 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 |
Galvanic & Galling Considerations
For pin-in-torx security 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 Pin-in-Torx Security Screws, class 10.9 or 12.9 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 Pin-in-Torx Security Screws Available in Property Class 8.8 Steel
| Thread size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Drive | Security bit | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|
| M3 | 0.5 | 5.6 | 2.4 | Pin-in-Torx | TR10 | 6~30 | ISO 14583 |
| M4 | 0.7 | 8.0 | 3.1 | Pin-in-Torx | TR20 | 8~40 | ISO 14583 |
| M5 | 0.8 | 9.5 | 3.7 | Pin-in-Torx | TR25 | 8~50 | ISO 14583 |
| M6 | 1.0 | 12.0 | 4.6 | Pin-in-Torx | TR30 | 10~60 | ISO 14583 |
| M8 | 1.25 | 16.0 | 6.0 | Pin-in-Torx | TR40 | 12~60 | ISO 14583 |
