Analysis of Causes of Delayed Fracture in 30MnSi Pre stressed PC Steel Bars and Improvement Measures
In response to the problem of delayed fracture of prestressed PC steel bars produced by downstream customers using 30MnSi wire rods during storage,transportation,and other processes,the causes were analyzed.The delayed fracture of PC steel bars and 30MnSi wire rods were studied,and the chemical composition,metallographic structure,macroscopic morphology of fracture surface,and non-metallic inclusions of prestressed PC steel bars were detected using a direct reading spectrometer and optical microscope.The microscopic morphology of the delayed fracture surface was observed using a scanning electron microscope,and the energy spectrum analysis of steel inclusions was conducted.After in-depth research,it was found that the main reason for the delayed fracture of PC steel bars is the presence of large levels of C-type inclusions inside the steel,and the secondary reason is the presence of martensite in the microstructure.By analyzing the causes and optimizing the heat treatment processes for smelting,continuous casting,and downstream deep processing,the problem of delayed fracture of PC steel bars in downstream deep processing products has been effectively solved.
PC steel roddelayed fractureinternal inclusions and abnormal tissuesheat treatment process
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