1 Introduction
2 Current state of knowledge
2.1 Non-metallic inclusions
2.2 Classic S-N curves
2.3 Experimental results in and above the very high cycle fatigue regime
2.3.1 Standard specimens
2.3.2 Gears
2.4 Modified S-N curves in the VHCF range
2.5 S-N curves based on stochastic distributions
2.6 Summary of the current state of knowledge
3 Systematic investigations of the bending fatigue strength of case-carburized, shot-peened gears in the VHCF range
3.1 Material variants, test gears and test rigs
Variant | V1–V8 | V9 | V10–V15, V18 | V16, V17 |
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Material | 16MnCr5, 20MnCr5 & 18NiCr5‑4 | 20MnCr5, 18CrNiMo7‑6 & 18CrMnMoNi9-5‑5 | 18CrNiMo7‑6 | |
Production route | Open melted & electro-slag-remelted (ESR) | |||
Continuous & ingot casting | ||||
Normal module mn in mm | 1.5 | 5 | 10 | |
Number of teeth of test gear | Pinion: 59 | 24 | 24 | |
Test rig | FZG back-to-back test rig & pulsator test rig | Pulsator test rig |
3.2 Experimental results
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Pulsator test rig:
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Normal module mn = 1.5 mm: 15 · 106 load cycles
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Normal module mn = 5 mm: 10 · 106 load cycles
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Normal module mn = 10 mm: 10 · 106 load cycles
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FZG back-to-back test rig: 30 · 106 load cycles