Property Class 12.9 Steel Hexalobular Socket Head Cap Screws combine the dimensional form of ISO 14579 with the material properties of grade ISO 898-1 property class 12.9: requires plating or black-oxide 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 12.9 Steel for Hexalobular Socket Head Cap Screws
The highest common strength class, for high-load machine assembly. For hexalobular socket head cap screws, 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 hexalobular socket head cap 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 Hexalobular Socket Head Cap 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 Hexalobular Socket Head Cap Screws Available in Property Class 12.9 Steel
| Size | Drive size | A (mm) | t_mean (mm) | Length range l (mm) | Reference standard |
|---|---|---|---|---|---|
| M2 | T6 | 1.75 | 0.8 | 3~20 | ISO 14579 |
| M2.5 | T8 | 2.4 | 1.0 | 4~25 | ISO 14579 |
| M3 | T10 | 2.8 | 1.2 | 5~30 | ISO 14579 |
| M4 | T20 | 3.95 | 1.7 | 6~40 | ISO 14579 |
| M5 | T25 | 4.5 | 1.9 | 8~50 | ISO 14579 |
| M6 | T30 | 5.6 | 2.3 | 10~60 | ISO 14579 |
| M8 | T45 | 7.95 | 3.2 | 12~80 | ISO 14579 |
| M10 | T50 | 8.95 | 3.8 | 16~100 | ISO 14579 |
| M12 | T55 | 11.35 | 5.0 | 20~120 | ISO 14579 |
| (M14) | T60 | 13.45 | 5.8 | 25~140 | ISO 14579 |
| M16 | T70 | 15.7 | 6.8 | 25~160 | ISO 14579 |
| (M18) | T80 | 17.75 | 7.8 | 30~180 | ISO 14579 |
| M20 | T90 | 20.2 | 9.0 | 30~200 | ISO 14579 |
Dimensions are independent of the material: every size above is available in Property Class 12.9 Steel.
Custom manufacturing · Made to drawing
Need this screw in a grade that is not listed?
Grade 12 9 Steel is one of the grades the catalog describes. Material and finish are usually what drives a special — a grade the standard part is not stocked in, or a coating chosen against a salt-spray figure instead of a default. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
