Abstract: With  increasing  the  strength  and  toughness  of pipeline  steel,the  corresponding  evolution  of structure  is pearlite-ferrite(X65    grade),acicular    ferite(X80    grade),particle    bainite-ferrite(X100    grade)and    lower    bainite(X120 grade).Grain refining and dispersed secondary phase are also important measures to increase the strength and toughness of pipeline steel. In general the structure of pipeline steel is improved by optimizing composition of steel and increasing cool- ing speed of control rolling process.

摘要： 随着管线钢强韧性的提高，其对应组织的演变为铁素体-珠光体型(X65级)、针状铁素体型( X80 级)、粒状贝氏体-铁素体型(X100级)和下贝氏体型(X120级)组织。晶粒细化和弥散的第2相亦是提高管线钢强 韧性的重要手段，通常通过钢的成分优化和提高控制轧制工艺的冷却速度改善管线钢的组织。