Effect of Cryogenic Treatment Times on Wear and Corrosion Resistance of E690 Steel

The effect of cryogenic treatment times at -190 ℃ for a total length of 6 h on the wear and corrosion resistance properties of marine steel E690 were studied. The metallographic structure of the sample was observed by optical microscope and the friction coefficient was measured by the friction-wear tester. The wear properties of different samples were compared by weight loss method. The wear morphologies were investigated by SEM. The polarization curves were measured at an electrochemical workstation. The results show that the relative wear rate of E690 steel decreases by 11.4% at most after cryogenic treatment. The maximum self-corrosion potential increases from -0.57 V to -0.43 V. The cryogenic treatment promotes the transformation of the micro-structure into martensite and bainite. Meanwhile, fine carbides are precipitated and dispersed in the matrix. As a result, E690 steel performance is improved. After 3 cycles of cryogenic, the properties of the samples reaches the optimum, and the properties of the samples change little after 4 cycles of cryogenic, among which the corrosion resistance is slightly reduced.