显微组织对X80管线钢力学性能的影响

Influence of Microstructure on the Mechanical Properties of X80 Pipeline Steel

利用光学显微镜研究了20mm厚度X80管线钢显微组织类型对强韧性的影响。结果表明：显微组织为针状铁素体和少量的粒状贝氏体时，钢的屈服强度达到512MPa；针状铁素体的晶粒细化、粒状贝氏体和板条贝氏体可以使X80管线钢具有更高的屈服强度，达到600MPa。细小而均匀的粒状贝氏体可以获得良好的冲击韧性。掺杂在一起的细小的针状铁素体、准多边形铁素体、粒状贝氏体促使裂纹扩展路径曲折，改善冲击韧性。

The influence of microstructure on the strength and toughness of X80 pipeline steel with thickness of 20mm by using optical microscope was studied. And the result showed that, when the microstructure was acicular ferrite and little granular bainite, the yield strength of steel could reach 512MPa; furthermore, the grain refinement of acicular ferrite, granular bainite and lath bainite could make the X80 pipeline steel with a higher yield strength, bainite could obtain a good impact toughne and it could be up to 600MPa. The small and uniform granular ss. The mixed microstructure of fine acicular ferrite, quasi-polygonal ferrite and granular bainite would urge the cracks to become tortuous, which could improve the impact toughness of the steel.