The corrosion resistance of Ti-Mo microalloyed steel was evaluated using the cyclic immersion corrosion testing machine and electrochemical workstation.The experiments combined the results from the optical microscope,X-ray diffractometer,scanning electron microscope,and atomic force microscope to discuss the influence factors of microstructure type on corrosion resistance.The results show that with the decrease of the proportion of pearlite and bainite in the investigated steel,the growth rate of the rust layer slows down,the proportion of the inner rust layer increases,the compactness of the rust layer and the bonding ability with the iron matrix are improved,and the corrosion weight loss rate decreases.At the same time,the self-corrosion current density of bare steel decreases,the charge transfer resistance increases,and the corrosion resistance improves.The microstructure potential of the investigated steel was measured,and the ferrite potential was higher than that of bainite and pearlite.As a microscopic corrosion cell was formed between the structures,the galvanic corrosion strength is the main factor affecting the corrosion rate.That is to say,reducing the volume fraction of bainite/pearlite in Ti-Mo high strength steel can improve microstructure uniformity,suppress galvanic corrosion,and enhance corrosion resistance.
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