Abstract
This paper presents the results of an experimental study of gas metal arc welded, GMAW, cruciform joints made of common construction steel S355. The hypothesis is that smooth undercuts in as welded conditions can give enhanced fatigue properties similarly as post treated welds. Undercuts are generally seen as a defect or imperfection. Welders try to avoid these and repair them when they occur, which result in increased production lead time. Post weld improvement methods i.e. grinding or high-frequency-impact treatment (HFMI) as fatigue-enhancing post-treatment methods enforce amongst other effects a certain smooth undercut-shaped groove in the treated weld toe region. The obtained shallower weld toe transition reduces the geometrical notch effect and increases fatigue strength. This paper presents a study whereas welded specimens with a weld toe geometry similar to what is obtained by weld toe grinding or HFMI-treatment, has been produced, fatigue tested and analyzed. The improvement of the fatigue strength is comparable to post-weld treated specimens. It has proven to be an efficient way to achieve high-quality welds without introducing any additional operations in production, thus enabling weight reduction using cost-effective methods.
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Acknowledgments
The authors would like to acknowledge the Swedish Agency for Innovation Systems, VINNOVA, for funding the research projects LIGHTSTRUCT (Lightweight high-performance welded structures) and WIQ (Weight reduction by improved weld quality). Gratitude to the KK-foundation for the support to the research school SiCoMap at University West and to Volvo Construction Equipment for the opportunity to perform research. Special appreciations also to Mr. Rasim Toptas at Volvo Construction Equipment in Braås, who welded the specimens and helped the authors to evolve the theories into practice.
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Recommended for publication by Commission XIII - Fatigue of Welded Components and Structures
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Åstrand, E., Stenberg, T., Jonsson, B. et al. Welding procedures for fatigue life improvement of the weld toe. Weld World 60, 573–580 (2016). https://doi.org/10.1007/s40194-016-0309-9
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DOI: https://doi.org/10.1007/s40194-016-0309-9