When Fender Washers are required in Grade 12.9 Steel, the alternative grades and the trade-offs between them matter as much as the dimensions. This page covers both, plus mechanical and corrosion data.
Why Choose Grade 12.9 Steel for Fender Washers
The highest common strength class, for high-load machine assembly. For fender washers, 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 fender washers 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 Fender Washers, 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 Fender Washers Available in Grade 12.9 Steel
| For bolt size | Inner diameter d1 min (mm) | Outer diameter d2 max (mm) | Thickness h (mm) | Reference standard | Notes |
|---|---|---|---|---|---|
| M3 | 3.2 | 9.0 | 0.8 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
| M4 | 4.3 | 12.0 | 1.0 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
| M5 | 5.3 | 15.0 | 1.2 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
| M6 | 6.4 | 18.0 | 1.6 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
| M8 | 8.4 | 24.0 | 2.0 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
| M10 | 10.5 | 30.0 | 2.5 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
| M12 | 13.0 | 37.0 | 3.0 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
| M14 | 15.0 | 44.0 | 3.0 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
| M16 | 17.0 | 50.0 | 3.0 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
| M20 | 21.0 | 60.0 | 4.0 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
| M24 | 25.0 | 72.0 | 5.0 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
| M30 | 31.0 | 90.0 | 6.0 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
| M36 | 37.0 | 110.0 | 8.0 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |