新型极地船用钢在模拟低温海水中的磨损-腐蚀耦合作用研究

分别采用正火和调质工艺对新型破冰船用低碳高强钢进行了热处理,并使用UMT-3多功能摩擦磨损试验机低温模块和摩擦电化学模块研究了其在低温模拟海水环境中不同外加电位下的磨损-腐蚀耦合行为.使用电子扫描显微镜和白光干涉显微镜对钢样的微观组织及磨痕形貌进行了表征,并对其在不同外加电位作用下的磨损-腐蚀机理进行了探讨.结果表明:两种热处理后的钢材的平均摩擦系数都随外加电位升高而降低,而磨痕深度、磨损量和腐蚀电流则随着外加电位升高而增加;钢材的开路电位随着磨损的发生逐渐负移,腐蚀电流密度增加;其中,经过正火处理的钢样磨痕表面主要出现剥落坑,而调质钢磨痕表面则主要出现了裂纹和腐蚀坑.正火钢磨损和腐蚀损失量所占比例分别为80.6%、19.4%,调质钢分别为55.1%、44.9%,两种钢材的磨损-腐蚀之间相互促进损失量ΔVW和ΔVC均为正值,证实磨损和腐蚀之间存在着相互协同作用.

Tribocorrosion Coupling Effect of Novel Polar Marine Steel in Simulated Low Temperature Seawater

The novel polar marine steel was heat-treated by the normalizing (N) and quenching and tempering (QT) processes. The tribocorrosion coupling effect of the heat-treated steels under different applied potentials in simulated low temperature seawater was investigated on a UMT-3 multifunctional friction and wear testing equipment equipped with low temperature and electrochemical modules. The microstructures and worn surface morphologies of the steels after the tribocorrosion tests were characterized by scanning electron microscopy (SEM) and white light interferometry. The tribocorrosion mechanisms under different applied potentials were also explored. Results showed that, as the applied potential increased, the average friction coefficients of the heat-treated steels decreased, while the wear depths, wear weights, and corrosion currents increased. During the tribocorrosion tests, the open circuit potentials of the heat-treated steels shifted negatively and the corresponding corrosion densities increased obviously. Peeling pits could be mainly observed on the worn surface of the N steel, while small cracks and etch pits dominated on the worn surface of the QT steel. The volume losses caused by the wear and corrosion for the N steel accounted for 80.6% and 44.9%, respectively, which became 55.1% and 44.9% for the QT steel. The wear and corrosion processes of both the N and QT steels were mutual positively promoted, evidencing the presence of the synergistic tribocorrosion coupling effects.