When E-Clips (External Snap Rings) 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 E-Clips (External Snap Rings)
The highest common strength class, for high-load machine assembly. For e-clips (external snap rings), 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 |
Corrosion Behavior in Service
Carbon and alloy steel e-clips (external snap rings) 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 e-clips (external snap rings) 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 E-Clips (External Snap Rings) Available in Grade 12.9 Steel
| Groove diameter (mm) | Shaft diameter range (mm) | Outside diameter (mm) | Thickness s (mm) | Reference standard | Notes |
|---|---|---|---|---|---|
| 1.2 | 1.4~2.0 | 3.0 | 0.3 | DIN 6799 | E-clip, radial-fit external retaining |
| 1.5 | 2.0~2.5 | 3.8 | 0.4 | DIN 6799 | E-clip, radial-fit external retaining |
| 1.9 | 2.5~3.2 | 4.8 | 0.4 | DIN 6799 | E-clip, radial-fit external retaining |
| 2.3 | 3.2~4.0 | 6.0 | 0.6 | DIN 6799 | E-clip, radial-fit external retaining |
| 3.2 | 4.0~5.0 | 7.4 | 0.6 | DIN 6799 | E-clip, radial-fit external retaining |
| 4.0 | 5.0~7.0 | 9.0 | 0.7 | DIN 6799 | E-clip, radial-fit external retaining |
| 5.0 | 7.0~9.0 | 11.0 | 0.7 | DIN 6799 | E-clip, radial-fit external retaining |
| 6.0 | 9.0~11.0 | 12.2 | 0.8 | DIN 6799 | E-clip, radial-fit external retaining |
| 7.0 | 11.0~14.0 | 14.3 | 0.9 | DIN 6799 | E-clip, radial-fit external retaining |
| 8.0 | 14.0~18.0 | 16.2 | 1.0 | DIN 6799 | E-clip, radial-fit external retaining |
| 9.0 | 18.0~24.0 | 18.0 | 1.0 | DIN 6799 | E-clip, radial-fit external retaining |
| 10.0 | 24.0~31.0 | 20.2 | 1.2 | DIN 6799 | E-clip, radial-fit external retaining |
| 12.0 | 31.0~38.0 | 23.2 | 1.2 | DIN 6799 | E-clip, radial-fit external retaining |
| 15.0 | 38.0~45.0 | 29.0 | 1.5 | DIN 6799 | E-clip, radial-fit external retaining |
| 19.0 | 45.0~55.0 | 37.0 | 1.75 | DIN 6799 | E-clip, radial-fit external retaining |
| 24.0 | 55.0~70.0 | 44.0 | 2.0 | DIN 6799 | E-clip, radial-fit external retaining |