2015:38 Evaluation of fatigue in austenitic stainless steel pipe components

Background

Transferability of experimental results obtained for smooth test specimens under constant amplitude loading to realistic components subjected to variable amplitude loading is an important issue in the design against fatigue.

There is a lack of experimental fatigue data for austenitic steel components and the present study is an important contribution to fill this gap.

Objective

The present study is aimed to investigate the margins of the ASME design curve for austenitic stainless steel, by performing fatigue experiments on a realistic welded austenitic stainless steel piping component. A particular focus is on high cycle fatigue and variable amplitude loading.

The main results from the study are:

  • The results indicate extensive conservatism in the ASME fatigue procedure. The ASME fatigue design procedure represents a survival probability in excess of the prescribed survival probability of 95 %.
  • A more detailed evaluation of the extent of the margins will largely depend on the weld fatigue reduction factor for the specific component.
  • The constant amplitude results indicated longer lives in comparison to the variable amplitude results.
  • The derivation of reliable design curves should be based on realistic variable amplitude loading.