中文摘要：

采用电子显微镜、扫描电镜（SEM）、极化曲线、电化学阻抗（EIS）等方法研究了Y对管线钢在3.5%Na Cl（%,质量分数）溶液中抗腐蚀性能的影响。结果表明：添加Y的试验钢比未添加Y的试验钢抗腐蚀性好。分析其原因是：一方面是因为Y有变质夹杂的作用。Y可以将大尺寸、尖角状的Al2O3夹杂变质为小尺寸、球状的稀土类夹杂,导致夹杂物评定级别降低。另一方面是因为两种管线钢形成的腐蚀内锈层对钢基有不同的作用：1^#试验钢内锈层对钢基有保护作用,而0^#试验钢内锈层可以起到加速腐蚀的作用。因此,在生产管线钢时向其中加入Y可以起到减弱腐蚀的作用,从而提高管线钢使用寿命。

英文摘要：

The effect of Y on the corrosion property of pipeline steel immersed in 3. 5% Na Cl（ %,mass fraction）solution was researched by means of electron microscope,SEM,polarization curves and electrochemical impedance spectroscopy. The results showed that test steel containing Y had a better anti-corrosion property than test steel without Y. The reasons for this are that： on the one hand,Y has the capability to change inclusions. The Y can change large and sharp Al2O3 inclusions into small and global rare earth inclusions,thus reducing grade of inclusions. On the other hand,two kinds of inner rust layers from pipeline steel have different effect to the steel base：inner rust layer from 1^# test steel has a protective effect to steel base,however,inner rust layer from 0^# test steel has an effect of accelerating corrosion. In order to improve the service life of the pipeline steel,it is useful to add moderate Y to the steel.