For cylindrical roller bearing in Grade 8.8 Steel, the controlling selection factors are corrosion exposure, strength requirement and service temperature. The grade data for Grade 8.8 Steel (class 8.8) is summarized below together with every size supplied.
Why Choose Grade 8.8 Steel for Cylindrical Roller Bearing — ISO / DIN (Series 114)
The workhorse medium-carbon alloy grade for structural joints. For cylindrical roller bearing — iso / din (series 114), this matters when requires plating (zinc) for corrosion protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | class 8.8 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | up to approx. +300 °C |
| Corrosion characteristic | Requires plating (zinc) for corrosion protection |
Corrosion Behavior in Service
Carbon and alloy steel cylindrical roller bearing — iso / din (series 114) 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 114) 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 114) Available in Grade 8.8 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 |