SEED Guides Shaft-loads Factors >

8.1 Residual Stress
Residual stress, in a shaft subject to fluctuating loads, affects the maximum allowable stress in service.

A compressive residual stress can improve the fatigue strength of a material by inhibiting crack initiation and growth.

Thus, manufacturing processes such as shot peening, hammering, and cold rolling, are preferrable to processes that result in tensile residual stress, such as chromium plating.

It is difficult to estimate a factor for residual stress, but it is unlikely to fall outside the range 0.5 < Ka <1.5.

In the absence of special treatment, a machined shaft would be expected to have Ka = 0.9.