Abstract: X65 pipeline steel was smelted by vacuum induction furnace. Metalloscope and scanning electron microscope were used to observe its microstructure. Electronic universal tester and electronic pendulum impact testing machine were used to measure its mechanical properties. The effect of rare earth element Ce addition on microstructure and mechanical property of X65 pipeline steel was studied. The results showed that Ce had obvious metamorphism on molten steel. The included foreign substance changed into globular rare earth compounds inclusion and the crystal grains were refined, and then the mechanical properties were improved. After different heat treatment processes, it was found that the process of finishing rolling at 860℃ and air cooling could promote the mechanical properties of X65 pipeline steel.

Key words: Ce, X65 pipeline steel, inclusion, mechanical property

摘要： 通过真空感应炉对X65管线钢进行重新冶炼，采用金相显微镜和扫描电镜进行组织观察，采用微机控制电子式万能实验机和电子式摆锤冲击实验机进行性能检测，研究了稀土Ce对X65管线钢的显微组织和力学性能的影响. 结果表明，稀土Ce的加入对钢液有明显的变质作用，使夹杂物变成球状的稀土化合物类夹杂并使晶粒细化，提高了X65管线钢的各项力学性能参数；不同热处理工艺表明，对于X65稀土管线钢，若采用860℃终轧温度并空冷，也能获得良好的力学性能.

关键词: Ce, X65管线钢, 夹杂物, 力学性能