
Fatigue 141
η
Λ
η, η
The relationship must only be regarded
as a
useful approximation. The condition for
failure is, for instance, affected by the sequence of the different load cycles.
7.3 Factors affecting the fatigue properties of metals
The main factors affecting the fatigue properties of a component are:
1 Stress concentrations caused by component design.
2 Corrosion.
3 Residual stresses.
4 Surface finish/treatment.
5 Temperature.
6 Microstructure of alloy.
7 Heat treatment.
Fatigue of a component depends on the stress amplitude attained, the bigger
the stress amplitude the fewer the stress cycles needed for failure. Stress
concentration ...