Particular fatigue resistance of stabilized stainless steel: Endurance limit, strength and ductility of fatigued steel

Jussi Solin (Corresponding author), Jouni Alhainen, Esko Arilahti, Tommi Seppänen, Wolfgang Mayinger

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

Abstract

Comprehensive experimental research on fatigue performance of niobium stabilized (type 347) X6CrNiNb1810mod steel has revealed particular features of cyclic performance. This paper reports and discusses on the endurance limit behavior studied by strain controlled HCF tests at room and elevated temperatures. In contrast to carbon steels, stainless steels can tolerate notable amounts of plastic strain and display broad hysteresis loops at and below endurance limit. Together with pronounced secondary hardening, this results to abrupt endurance limit behavior. The modified Miner rule with S-N -curves extrapolated to low amplitudes is generally applicable for carbon steels, but not for stainless. Effectiveness of the endurance limit even with variable amplitude straining was shown for 347 type steel. Extrapolation of e-N curves beyond a few million cycles is conservative. An increase of temperature decreases, but does not vanish the endurance limit. Another peculiar feature of the studied stainless steel is its superior ductility, which is not affected by partial fatigue 'damage'. Five LCF tests at 325°C and 0.22 = ea = 0.5% were interrupted beyond the half-life condition (N/N25 = 0.5) at 0.5 = CUF = 0.9. Cyclic straining was directly followed by monotonic pulling to fracture. Surprisingly low correlation between tensile properties and fatigue usage was observed. The ultimate tensile strength was preserved within 10 MPa (2.5%) in all cases. Yield strength and elongation remained practically unchanged by pre-fatigue. This paper provides new experimental results. They are discussed together with earlier observations on the same steel extracted from a pipe, which has been manufactured for use in primary loop of a German NPP.

Original languageEnglish
Title of host publicationASME 2019 Pressure Vessels and Piping Conference, PVP 2019
Subtitle of host publicationCodes and Standards
PublisherAmerican Society of Mechanical Engineers ASME
Number of pages7
Volume1
ISBN (Electronic)978-0-7918-5892-9
DOIs
Publication statusPublished - 2019
MoE publication typeA4 Article in a conference publication
EventASME 2019 Pressure Vessels and Piping Conference, PVP 2019 - San Antonio, United States
Duration: 14 Jul 201919 Jul 2019

Conference

ConferenceASME 2019 Pressure Vessels and Piping Conference, PVP 2019
CountryUnited States
CitySan Antonio
Period14/07/1919/07/19

Keywords

  • Endurance limit
  • Fatigue
  • Stainless
  • Strain

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    Solin, J., Alhainen, J., Arilahti, E., Seppänen, T., & Mayinger, W. (2019). Particular fatigue resistance of stabilized stainless steel: Endurance limit, strength and ductility of fatigued steel. In ASME 2019 Pressure Vessels and Piping Conference, PVP 2019: Codes and Standards (Vol. 1). [PVP2019-93317] American Society of Mechanical Engineers ASME. https://doi.org/10.1115/PVP2019-93317