AISI 347 austenitic steel is, as an example, used in nuclear energy piping systems. Piping
filled with superheated steam or cooled water is particularly exposed to high stresses, whereupon
local material properties in the pipes can change significantly, especially in the case of additional
corrosive influences, leading to aging of the material. In the absence of appropriate information, such
local material property variations are currently covered rather blanketly by safety factors set during
the design of those components. An increase in qualified information could improve the assessment
of the condition of such aged components. As part of the collaborative project “Microstructure-based
assessment of the maximum service life of core materials and components subjected to corrosion and
fatigue (MiBaLeB)”, the short-time procedure, StrainLife, was developed and validated by several
fatigue tests. With this procedure, a complete S–N curve of a material can be determined on the
basis of three fatigue tests only, which reduces the effort compared to a conventional approach
significantly and is thus ideal for assessing the condition of aged material, where the material is often
rare, and a cost-effective answer is often very needed. The procedure described is not just limited to
traditional parameters, such as stress and strain, considered in destructive testing but rather extends
into parameters derived from non-destructive testing, which may allow further insight into what
may be happening within a material’s microstructure. To evaluate the non-destructive quantities
measured within the StrainLife procedure and to correlate them with the aging process in a material,
several fatigue tests were performed on unnotched and notched specimens under cyclic loading at
room and elevated temperatures, as well as under various media conditions, such as distilled water
and reactor pressure vessel boiling water (BWR) conditions