Residual stress effects during near-threshold fatigue crack growth

W. Geary*, J.E. King

*Corresponding author for this work

    Research output: Contribution to journalArticle

    Abstract

    The fatigue crack propagation behaviour of a low alloy, boron-containing steel has been examined after austenitizing at 900°C or 1250°C and tempering at a range of temperatures up to 400°C. Fatigue threshold values were found to vary with austenitizing and tempering treatment in a range between 3.3 to 6 MPa √m when tested at a stress ratio (R) of 0.2. Crack propagation rates in the Paris regime were insensitive to heat treatment variations. The crack propagation path was essentially transgranular in all conditions with small regions of intergranular facets appearing at growth rates around the knee of the da/dN vs ΔK curve. The crack front shape showed marked retardation in the centre of the specimen at low tempering temperatures. Experimental determinations and computer predictions of residual stress levels in the specimens indicated that this was due to a central residual compressive stress resulting from differential cooling rates and the volume change associated with the martensite transformation. The results are discussed in terms of microstructural and residual stress effects on fatigue behaviour. © 1987.

    Original languageEnglish
    Pages (from-to)11-16
    Number of pages6
    JournalInternational Journal of Fatigue
    Volume9
    Issue number1
    DOIs
    Publication statusPublished - Jan 1987

    Keywords

    • C-Mn-B steel
    • fatigue
    • fatigue crack propagation
    • fatigue threshold
    • heat treatment
    • residual stress

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