Specifying Wedge / Taper Washer — GB/T 852 (Series 084) in Grade 12.9 Steel pairs the dimensional form of Wedge / Taper Washer — GB/T 852 (Series 084) (GB/T 852) with the engineering properties of Grade 12.9 Steel. This page explains when to choose the grade, how it behaves in service, and which grades to compare it against.
Why Choose Grade 12.9 Steel for Wedge / Taper Washer — GB/T 852 (Series 084)
The highest common strength class, for high-load machine assembly. For wedge / taper washer — gb/t 852 (series 084), 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 wedge / taper washer — gb/t 852 (series 084) 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 Wedge / Taper Washer — GB/T 852 (Series 084), 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 Wedge / Taper Washer — GB/T 852 (Series 084) Available in Grade 12.9 Steel
| For bolt size | Inner diameter d1 (mm) | Outer diameter d2 (mm) | Mean thickness t (mm) | Slope | Reference standard |
|---|---|---|---|---|---|
| M3 | 3.5 | 6 | 1.2 | 1:6 | DIN 6917 / GB/T 853 |
| M4 | 4.5 | 8 | 1.6 | 1:6 | DIN 6917 / GB/T 853 |
| M5 | 5.5 | 11 | 2.0 | 1:6 | DIN 6917 / GB/T 853 |
| M6 | 6.5 | 13 | 2.4 | 1:6 | DIN 6917 / GB/T 853 |
| M8 | 8.5 | 17 | 3.2 | 1:6 | DIN 6917 / GB/T 853 |
| M10 | 10.5 | 22 | 4.0 | 1:6 | DIN 6917 / GB/T 853 |
| M12 | 12.5 | 26 | 4.8 | 1:6 | DIN 6917 / GB/T 853 |
| M14 | 14.5 | 30 | 5.6 | 1:6 | DIN 6917 / GB/T 853 |
| M16 | 16.5 | 35 | 6.4 | 1:6 | DIN 6917 / GB/T 853 |
| M18 | 18.5 | 39 | 7.2 | 1:6 | DIN 6917 / GB/T 853 |