Influence of hydrogen on tensile and fatigue life properties of 304/308 austenitic stainless steel butt welded joints

Saburo Okazaki, Hisao Matsunaga, Masami Nakamura, Saburo Matsuoka, Shigeru Hamada

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

To investigate the influence of hydrogen on the tensile and fatigue life properties of welded joints of 304/308 austenitic stainless steels, slow strain rate tensile (SSRT) tests and fatigue life tests were conducted in laboratory air using hydrogen exposed specimens. The specimens were fabricated from welded plates, and to elucidate the role of weld structure on hydrogen-induced degradation, the welded joint was solution-treated. In the SSRT tests of the as-welded (AW) joint, a non-exposed specimen failed at the base metal (BM), whereas a hydrogen-exposed specimen failed near the weld toe. In the case of the solution-treated-welded (STW) joint, the non-exposed specimen failed at the part of solution treated weld metal, whereas an H-exposed specimen failed near the weld toe. As a result, internal hydrogen significantly degraded the elongation of the AW joint. In the fatigue test, all the specimens failed near the weld toe. Internal hydrogen degraded the fatigue life considerably. However, the pre-charging led to little, if any, reduction in the fatigue limit. Similarly to the AW joint, hydrogen gas exposure notably degraded the fatigue life of the STW joint and led to little reduction in the fatigue limit. To investigate the relationship between the hydrogen-induced degradation and strain-induced martensitic transformation during fatigue testing, the volume fraction of ferrite in the broken specimens was measured by a ferrite scope. The volume fraction of martensitic transformation increased with an increase in the stress amplitude. These experimental results implied that the hydrogen-induced fatigue life degradation in the welded joint was closely related to the martensitic transformation during the fatigue process. The mechanisms of both the degradation in fatigue life and non-degradation in fatigue limit will be discussed further.

Original languageEnglish
Title of host publicationMaterials and Fabrication
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791851685
Publication statusPublished - Jan 1 2018
EventASME 2018 Pressure Vessels and Piping Conference, PVP 2018 - Prague, Czech Republic
Duration: Jul 15 2018Jul 20 2018

Publication series

NameAmerican Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
Volume6B-2018
ISSN (Print)0277-027X

Other

OtherASME 2018 Pressure Vessels and Piping Conference, PVP 2018
CountryCzech Republic
CityPrague
Period7/15/187/20/18

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering

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  • Cite this

    Okazaki, S., Matsunaga, H., Nakamura, M., Matsuoka, S., & Hamada, S. (2018). Influence of hydrogen on tensile and fatigue life properties of 304/308 austenitic stainless steel butt welded joints. In Materials and Fabrication (American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP; Vol. 6B-2018). American Society of Mechanical Engineers (ASME).