Very Long Life Fatigue Behavior of Q345 Bridge Steel

Abstract:

Using the ultrasonic fatigue testing technique, specimens of Q345 bridge steel with two types of shape (round and plate) were performed in ambient air at room temperature with a stress ratio of R=-1. The very long life fatigue property of Q345 was studied and the initiation mechanisms of fatigue cracks were investigated and analyzed with SEM. The results show that the two types of specimen present different S-N curve characteristics in the region of 105-109 cycles. The S-N curve of round specimens shows continuously decreasing tendency, while the S-N curve of plate specimens has a steep decreasing step and an asymptotic horizontal one. The fatigue strength of round specimen is higher than that of plate specimen. Fatigue failure initiates from the surface before 107cycles with high stess level while at internal inclusion in the very long life fatigue regime.

• Periodical: Applied Mechanics and Materials (Volumes 217-219)
• Pages: 407-410
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.217-219.407
• Online since: November 2012
• Authors: Xiao Zhao
• Keywords: Crack Initiation, Q345, S-N Curve, Very Long Life Fatigue

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