The Corrosion Resistance And Mechanical Properties Of Ferritic Weathering Steel With Precipitation Strengthening

In this paper,the ferritic weathering steel with precipitation strengthening is taken as research project,the corrosion resistance and the electrochemical behavior of the bare samples and rust samples of test steels are studied by periodic immersion corrosion test.Based on these,through the hot-rolling experiments,the effect of coiling temperatures on the mechanical properties of test steels is studied.The main works and results are as follows:?1?The composition of ferritic weathering steel with precipitation strengthening is designed.The ability of corrosion resistance is gotten by calculating the corrosion rate of test steels based on periodic immersion corrosion test.By observing and analyzing the microstructure of rust layer,different test steels have different rust layer,so its protective for substrate is different.By XRD analyzing,the rust layer is composed by ?-FeOOH,?-FeOOH and Fe₃O₄,and the amount of these corrosion products is different in weathering steels with different alloy elements.Examination of the cross-sections of the rust layers by EPMA shows the distributions of alloying elements.?2?The electrochemical behavior of bare samples and rusted samples of weathering steels is analyzed by electrochemical workstation.The effect of different alloy elements on the rust layer generation process and the protection mechanism of rust layer is studied by polarization curves measurement.The equivalent circuit and the mechanism of electrochemical are gotten by EIS measurement.?3?By the hot-rolling experiments of test steels,it is concluded that the size of ferrite is minimized and the mechanical property is improved with the decreasing of coiling temperatures,however,lower coiling temperature will reduce the toughness of weathering steel.The influence of the amount of alloy elements on the type of precipitation is analyzed by TEM.