X90管线钢的组织和性能特征

Microstructure and properties of X90 pipeline steel

借助金相电镜、扫描电镜（SEM）、电子背散射衍射（EBSD）和透射电镜（TEM）系统研究了第三代X90多相组织管线钢的显微组织和性能,并对试制的X90管线钢板/管各项性能进行了统计分析。结果表明：复合添加Nb、Mo、Ti微量合金元素,配合轧制和多相组织调控工艺可以生产出细化的＂软硬相＂匹配良好的铁素体、贝氏体、M-A岛等多相多尺度混合组织,组织中＂软硬相＂比例约为3∶2;所开发的多相组织X90管线钢晶粒度达到12级,大角度晶界达到80%,屈强比在0.85以下,均匀伸长率在7.5%以上;经过试制管后,钢板/钢管性能变化稳定,成形性能优异,焊接性能良好,实现了第三代X90管线钢的工程应用。

The microstructure and properties of a third generation X90 multi-phase pipeline steel were studied by means of metallographic microscope,scanning electron microscope（ SEM）,electron backscatter diffraction（ EBSD）,and transmission electron microscope（ TEM）,and the properties of the tested X90 pipeline steel plate/tube were analyzed.The results show that the refined multi-scale hybrid microstructure of ferrite,bainite and M-A islands etc can be obtained by the composite indium addition of alloying elements Nb,Mo,and Ti,with rolling and multi-phase control technology,and the soft and hard phases in the microstructure have a good match,with the phase ratio is about 3∶2.For the developed multi-phase X90 pipeline steel,the grain size number is 12,the large angle boundary ratio reaches 80%,the yield ratio is below 0.85 and the uniform elongation is more than 7.5%.After trial manufacture of pipe,the material also has stable change of steel/pipe performance,excellent forming performance,good welding performance,the developed third generation of X90 pipeline steel is realized its engineering application.