317L/FH40复合板在不同温度下摩擦-腐蚀耦合作用机理研究

Friction-corrosion Performance of Steels and Their Welding Zone for Composite Plate of 317L Stainless Steel/FH40 Low-temperature Marine Steel in Simulated Sea Waters at Different Temperatures

针对在极地环境使用的特殊海水-海冰摩擦-腐蚀耦合作用环境,使用UMT-2型多功能摩擦磨损实验机分别测试了新型FH40级低温钢板、抗海水腐蚀性能优异的317L不锈钢以及两种钢板焊接部位在不同条件下的往复摩擦-腐蚀耦合行为;使用金相显微镜、白光干涉仪以及扫描电子显微镜表征了钢样的显微组织形貌和磨痕形貌。结果表明:随着环境温度从20℃降低到-20℃,FH40钢及焊缝处的摩擦系数和磨损量都明显增加,而317L不锈钢变化不大;值得关注的是,在海水环境中进行摩擦测试时,可见317L不锈钢的整体损失量远远低于FH40钢及焊缝处的,证明317L不锈钢可应用于极地破冰船船体外表面。另外,使用电化学阻抗、极化技术测试了钢材耐蚀性能,以期确定低温环境对复合钢板耐蚀性的影响。结果证明复合板焊缝处在常温及低温条件下,腐蚀速率皆低于FH40低温钢,两种钢板复合仍保持良好耐蚀性。

The performance of friction and corrosion of FH40 steel, 317L stainless steel and their welding zone of the explosive formed composite plate of FH40 steel/317L stainless steel was studied via UMT-2 multifunctional friction-wear tester with a grinding ball of alumina(Al2O3) in simulated environments of sea water and sea ice, respectively at different temperatures. Their microstructure and wear morphology were characterized by metallographic microscope, white light interferometer and scanning electron microscope. The results showed that with the decrease of temperature, from 20 ℃ to-20 ℃, the friction coefficient and wear loss of FH40 steel and the welding zone increase significantly, while 317L stainless steel changed only little. It should be emphasized on that the wear and corrosion loss of 317L stainless steel is much lower than that of FH40 steel and the welding zone in sea water, which confirmed the feasibility of 317L stainless steel as the shell material for icebreaker. In addition, the corrosion resistance of the steels was also assessed by means of measurements of electrochemical impedance and polarization curves in order to determine the effect of low temperature environment on the corrosion resistance of composite steel plate. The results showed that the corrosion rate of the welding zone was lower than FH40 steel both at room temperature and low temperature.