STP942: Effect of Nitrogen on Creep-Fatigue Interaction in Austenitic Stainless Steels at 600°C

    Nilsson, J-O
    Research Metallurgist, Research & Development Centre, Mechanical Metallography, AB Sandvik Steel, Sandviken,

    Pages: 15    Published: Jan 1988


    Abstract

    Three austenitic stainless steels (AISI 316, AISI 316LN, and 253MA) have been investigated at 600°C with respect to fatigue and creep-fatigue behavior. Transmission electron microscopy showed that cross-slip and climb of dislocations are inhibited in AISI 316LN and 253MA due to the presence of nitrogen in solid solution. This results in a planar slip character and a concomitant increase in fatigue strength. However, during creep-fatigue deformation, nitrogen has an adverse effect on strength. This can be explained as an enhanced interaction between creep and fatigue due to the generation of high stresses in the grain boundary regions, caused by inhibited recovery.

    Keywords:

    low-cycle fatigue, high-temperature fatigue, creep-fatigue interaction, intergranular fracture, austenitic stainless steels


    Paper ID: STP24505S

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP24505S


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