Grade 8.8 Steel (class 8.8) is the workhorse medium-carbon alloy grade for structural joints. When tapered roller bearing are specified in this grade, the dimensions remain per ISO / DIN; the material determines corrosion behavior (requires plating (zinc) for corrosion protection) and the service temperature range (up to approx. +300 °C). Both are covered below with the size table.
Why Choose Grade 8.8 Steel for Tapered Roller Bearing — ISO / DIN (Series 116)
The workhorse medium-carbon alloy grade for structural joints. For tapered roller bearing — iso / din (series 116), 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 |
Galvanic & Galling Considerations
For tapered roller bearing — iso / din (series 116) 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 Tapered Roller Bearing — ISO / DIN (Series 116), class 10.9 or 12.9 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 Tapered Roller Bearing — ISO / DIN (Series 116) Available in Grade 8.8 Steel
| Bore d (mm) | Outer diameter D (mm) | Total width T (mm) | Cone angle (deg) | Dynamic load C (kN) | Reference standard |
|---|---|---|---|---|---|
| 20 | 47 | 15.25 | 15 | 30.0 | ISO 355 / GB/T 297 |
| 25 | 52 | 16.25 | 15 | 34.0 | ISO 355 / GB/T 297 |
| 30 | 62 | 17.25 | 15 | 49.5 | ISO 355 / GB/T 297 |
| 35 | 72 | 18.25 | 15 | 69.0 | ISO 355 / GB/T 297 |
| 40 | 80 | 19.75 | 15 | 81.5 | ISO 355 / GB/T 297 |
| 50 | 90 | 21.75 | 15 | 93.0 | ISO 355 / GB/T 297 |
| 60 | 110 | 23.75 | 15 | 142 | ISO 355 / GB/T 297 |
| 80 | 140 | 28.25 | 15 | 224 | ISO 355 / GB/T 297 |