| The bainitic rail is vulnerable to environmental corrosion during service,which leads to safety problems.Therefore,it is of great significance to study the corrosion behavior of bainitic steel for frog.In this paper,the effect of retained austenite on the corrosion behavior of high carbon bainitic steel was investigated by electrochemical measurement,wear corrosion test,and salt spray corrosion experiment.The microstructure of high carbon bainitic rail steel was characterized by dilatometer,scanning electron microscope and transmission electron microscope.By changing isothermal time,bainitic steels with 28.2 vol.%(RA–28),22.6 vol.%(RA–22)and 15.8 vol.%(RA–15)retained austenite were successfully obtained.The length and thickness of the bainitic ferrite laths in the samples treated by three processes respectively were basically the same.The electrochemical measurement results show that the corrosion of retained austenite precedes that of bainitic ferrite.With the decrease of retained austenite contents,the corrosion current density decrease,the polarization resistance increased and the galvanic effect between retained austenite and bainitic ferrite weakens,and the number of micro cells decreases,thus the corrosion resistance of the sample is reduce.Average roughness reduce.The results of wear corrosion show that the decrease of retained austenite contents can improve the wear corrosion performance and reduce the corrosion rate.The results of salt spray tests show that the main types of corrosion products of bainitit steel with different retained austenite contents are the same,and the corrosion products accumulate with the increase of corrosion time.Although the rust layer can enhance the protective effect of the material,the rust layer with different retained austenite contents has a different protective effect on the sample.With the decrease of retained austenite contents,the rust layer has a better protective effect and better corrosion resistance. |
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