中文摘要：

研究在管线钢中添加不同Mo含量以及控制冷却速度实现管线钢的组织优化。用Formast—F热膨胀仪测定实验钢的连续冷却转变曲线，用金相显微镜观察显微组织，分析了管线钢中Mo对连续冷却转变的影响规律。结果表明：添加Mo能够强烈抑制先共析铁素体和粒状贝氏体的形成，扩大形成下贝氏体的冷却速度范围；添加0．3％Mo元素能够最有效的细化晶粒。

英文摘要：

Optimizing microstructure of pipeline steel was realized by adding different content of molybdenum and controlling cooling rate. The continuous cooling tranformation curves of the steels were measured by Formast-F thermal expansion instrument and the microstructure was observed by optical microscope. The role of molybdenum in the continous cooling transformation of the steels was investigated. As a result, formation of proeutectoid ferrite and granular bainite is repressed by adding molybdenum in the pipeline steel and the range of cooling rate for forming lower bainite is enlarged. Grain size of the pipeline steel is refined most effectively when adding 0.3 % Mo.