水下摩擦螺柱焊接头在饱和CO2中的电化学性能

Electrochemical Performance of Underwater Friction Stud Welding Joint in CO_(2)Saturated NaCl Solution

以X65钢为焊接基板,16Mn钢为螺柱,利用摩擦螺柱焊(FSW)技术获得水下FSW接头,研究了接头和X65钢在通入饱和CO_(2)的NaCl溶液中的电化学腐蚀性能。利用光学显微镜观察试样的宏观和微观金相,利用SEM观测FSW接头腐蚀8 h后的腐蚀形貌,并结合XRD和EDS分析接头腐蚀产物的成分和元素。结果表明:FSW接头整体的开路电位更正、阻抗更大、腐蚀电流密度更小,说明FSW接头的耐腐蚀性整体比X65管线钢要好;FSW接头各个区域中,焊缝区和塞棒区腐蚀较轻,而上热影响区、下热影响区和母材区腐蚀较严重;FSW接头试样在饱和CO2的NaCl溶液中的腐蚀产物为Fe_(2)O_(3)。

The underwater friction stud welding(FSW)joint was obtained with X65 steel as substrate and 16Mn steel as stud.The electrochemical corrosion performance of the FSW joint and X65 steel in NaCl solution saturated with CO_(2)were studied by means of electrochemical methods,macroscopic-and microscopic-metallography,scanning electron microscope(SEM)with energy spectrum analyzer(EDS)and Xray diffractometer(XRD).The results show that the open circuit potential of FSW joint is more positive,the impedance is larger and the corrosion current density is smaller,which indicates that the corrosion resistance of FSW joint is better than that of X65 pipeline steel.According to the microscopic metallography observation for every zone of the FSW joint,it is found that the corrosion in central welded zone is lighter,while the corrosion in upper heat affected zone,lower heat affected zone and base metal zone is more serious.The EDS and XRD results showed that the corrosion product of FSW joints is Fe_(2)O_(3).