Grade 12.9 Steel Cylindrical Roller Bearing — ISO / DIN (Series 139) pairs the standard ISO / DIN with a Grade 12.9 Steel base material. The sections below cover why engineers select this grade for cylindrical roller bearing — iso / din (series 139), its corrosion and temperature behavior, and the sizes available.
Why Choose Grade 12.9 Steel for Cylindrical Roller Bearing — ISO / DIN (Series 139)
The highest common strength class, for high-load machine assembly. For cylindrical roller bearing — iso / din (series 139), 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 cylindrical roller bearing — iso / din (series 139) 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 cylindrical roller bearing — iso / din (series 139) 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 Cylindrical Roller Bearing — ISO / DIN (Series 139) Available in Grade 12.9 Steel
| Bore d (mm) | Outer diameter D (mm) | Width B (mm) | Dynamic load C (kN) | Limit speed (rpm) | Reference standard |
|---|---|---|---|---|---|
| 20 | 47 | 14 | 28.4 | 11000 | ISO 246 / GB/T 283 |
| 25 | 52 | 15 | 33.5 | 10000 | ISO 246 / GB/T 283 |
| 30 | 62 | 16 | 49.5 | 8500 | ISO 246 / GB/T 283 |
| 35 | 72 | 17 | 67.0 | 7500 | ISO 246 / GB/T 283 |
| 40 | 80 | 18 | 78.0 | 6700 | ISO 246 / GB/T 283 |
| 50 | 90 | 20 | 93.0 | 6000 | ISO 246 / GB/T 283 |
| 60 | 110 | 22 | 138 | 5000 | ISO 246 / GB/T 283 |
| 75 | 130 | 25 | 180 | 4300 | ISO 246 / GB/T 283 |
| 90 | 160 | 30 | 238 | 3600 | ISO 246 / GB/T 283 |