Very long life fatigue tests were carried out on 16Mn steel base metal and its welded joint by using the ultrasonic fatigue testing technique. Specimen shapes (round and plate) were considered for both the base metal and welded joint. The results show that the specimens present different S-N curve characteristics in the region of 105-109 cycles. The round specimens showed continuously decreasing tendency while plate specimens showed a steep decreasing step and an asymptotic horizontal one. The fatigue strength of round specimen was found higher than plate specimen. The fatigue strength of as-welded joint was 45.0% of the base material for butt joint and 40% for cruciform as-welded joint. It was found that fracture can still occur in butt joint beyond 5x6 cycles. The cruciform joint has a fatigue limit in the very long life fatigue regime (107-109 cycles). Fatigue strength of butt as-welded joint was much higher as compared to cruciform as-welded joint. Improvement in fatigue strength of welded joint was found due to UPT. The observation of fracture surface showed crack mainly initiated from welded toe at fusion areas or geometric discontinuity sites at the surface in butt joint and from welded toe in cruciform joint.
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- 16 Mn
- very high cycle fatigue
- welded joint
- S-N curve
- crack initiation mechanism
Liu, Y., He, C., Huang, C., Khan, M. K., & Wang, Q. (2014). Very long life fatigue behaviors of 16Mn steel and welded joint. Structural Engineering and Mechanics, 52(5), 889-901. https://doi.org/10.12989/sem.2014.52.5.889