Fatigue strength of spring steel with small scratches

Y. Nishimura, K. Yanase, Y. Ikeda, Y. Tanaka, N. Miyamoto, S. Miyakawa, M. Endo
  • Fatigue & Fracture of Engineering Materials & Structures, February 2018, Wiley
  • DOI: 10.1111/ffe.12793

Torsional fatigue strength of a high-strength spring steel, SWOSC-V, with small scratches

Photo by Nikola Treći on Unsplash

Photo by Nikola Treći on Unsplash

What is it about?

We performed a series of fatigue tests to examine the torsional fatigue behavior of a high-strength spring steel (JIS G 3561, SWOSC-V) in the presence of small scratches. Based on the square-roo-area parameter model, we investigated the sensitivity of the hard steel to small scratches in HCF (high cycle fatigue) and VHCF (very high cycle fatigue) regimes.

Why is it important?

1) Peculiar fatigue behavior in the VHCF regime was not observed. 2) Non-propagating mode I cracks were observed at the root of scratch at fatigue limit. 3) The square-root-area parameter model is applicable even for small scratches, and the scratch depth, t, has the significant effect. However, the torsinal fatigue strength slightly depends on the mismatch angle between the scratch direction and the principal stress direction.

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http://dx.doi.org/10.1111/ffe.12793

The following have contributed to this page: Masahiro Endo and Prof Keiji Yanase