iso fAILURE mode classification for gears (ISO 10825)
▶ View photo: a second, distinct gear damage exampleView photo: a second, distinct gear damage example
Failure modes of various machine elements are presented in chapter 7
Table 7.1: Failure mode classification for gears (ISO 10825).
1. Indications of
surface disturbances		 1.1 Sliding wear 1.1.1 Normal wear
(Running in wear)
1.1.1.1 Moderate wear
1.1.1.2 Polishing
1.1.2 Abrasive wear
1.1.3 Excessive wear
1.1.4 Moderate scratching
(Scoring)
1.1.5 Severe scratching
1.1.6 Interference wear
1.2 Corrosion 1.2.1 Chemical corrosion
1.2.2 Fretting corrosion
1.2.3 Scaling
1.3 Overheating
1.4 Erosion 1.4.1 Cavitation erosion
1.4.2 Hydraulic erosion
1.5 Electric erosion
2. Scuffing
3. Permanent
deformations		 3.1 Indentation
3.2 Plastic deformation 3.2.1 Plastic deformation
by rolling
3.2.2 Plastic deformation
by tooth hammer
3.3 Rippling
3.4 Ridging
3.5 Burrs
4. Surface fatigue
phenomena		 4.1 Pitting 4.1.1 Initial pitting
4.1.2 Progressive pitting
4.1.3 Micro pitting
4.2 Flake pitting
4.3 Spalling
4.4 Case crushing
5. Fissures and cracks 5.1 Hardening cracks
(Quench cracks)
5.2 Grinding cracks
5.3 Fatigue cracks
6. Tooth breakage 6.1 Overload breakage 6.1.1 Brittle fracture
6.1.2 Ductile fracture
6.1.3 Semi-brittle fracture
6.2 Tooth shear
6.3 Breakage after
plastic deformation
(Smeared fracture)
6.4 Fatigue breakage 6.4.1 Bending fatigue
6.4.2 Tooth breakage