Effect of microstructure on fatigue crack growth behavior of surface‐ and middle‐layer materials of thick high‐strength bridge steel plates

The effects of microstructure on the fatigue crack growth behavior of surface‐ and middle‐layer materials of high‐strength bridge steel (including steel Q370qE, Q420qE, and Q500qE) plates were investigated. The microstructures are captured via an optical microscope, and fracture morphologies are exa...

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Bibliographic Details
Published in:Fatigue & fracture of engineering materials & structures 2023-02, Vol.46 (2), p.485-500
Main Authors: Ke, Lu, Li, Youlin, Chen, Zheng, Feng, Zheng, Yan, Banfu, Zhu, Furui, Yuan, Peng
Format: Article
Language:English
Subjects:
Crack propagation
fatigue crack growth
Fatigue cracks
Fatigue failure
fatigue fracture morphology
Fractions
Fracture mechanics
Grain size
high‐strength steel
Metal fatigue
microstructural characteristic
Microstructure
Morphology
Optical microscopes
Steel plates
Striations
Structural steels
tensile property
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Summary:The effects of microstructure on the fatigue crack growth behavior of surface‐ and middle‐layer materials of high‐strength bridge steel (including steel Q370qE, Q420qE, and Q500qE) plates were investigated. The microstructures are captured via an optical microscope, and fracture morphologies are examined by scanning electron microscopy. The results indicate that for materials with different strength grades of steel plates at the same sampling locations, the higher the strength grade, the lower the fatigue crack growth rate (FCGR). In addition, materials with smaller equivalent grain sizes or higher volume fractions of the second hard phase exhibit lower FCGR for the surface‐ and middle‐layer materials of the identical strength‐grade steel plate. The fatigue fracture morphological examination results show that typical fatigue striations along with secondary cracks are observed in the stable crack growth region of three high‐strength bridge steel plates. Moreover, fatigue steps are observed in steel Q500qE, which has the lowest FCGR, indicating that the fatigue steps contribute significantly to resisting the fatigue crack propagation. Highlights The microstructural characteristics of thick high‐strength bridge steel plates were investigated. The tensile properties and fatigue crack growth rates of the surface‐ and middle‐layer materials were compared. The effects of microstructural characteristics on the fatigue crack growth behavior were revealed. Fatigue fracture features of thick high‐strength steel plates were examined.
ISSN:8756-758X
1460-2695
DOI:10.1111/ffe.13879