摘要
测定了一种低C高Nb和一种低C高Nb加Mo X80级管线钢的动态连续冷却转变曲线,通过光学显微镜、扫描电镜和透射电镜观察两钢不同条件下的显微组织和细微组织的形貌特征。结果表明,随着冷速的增加,两钢的组织由多边形铁素体、准多边形铁素体转变为针状铁素体,同时晶粒得到细化;试验钢组织在低冷速时变化较明显,当冷速大于5℃/s时组织类型变化不明显,此时主要是组织均匀性及M-A岛发生变化,随冷速增加M-A岛更细小、弥散;Mo使CCT曲线中针状铁素体转变线右移,促进针状铁素体组织形成。
CCT curves of Nb microalloyed and Nb-Mo microalloyed X80 pipeline steels were determined. Microstructure of the steels under different processing conditions were investigated by means of optical microscope, scanning electronic microscopy and transmission electron microscopy. The results show that microstructure of the steels changes from polygonal ferrite and quasi-polygonal ferrite to acicular ferrite with increase of cooling rates and the grains are refined at the same time. Significant change of the microstructure is observed at low cooling rates, when cooling rates exceed 5℃/s, microstrueture which consists of acicular ferrite and M-A islands remains unchanged, but it becomes more uniform and M-A islands are finer and more dispersed. Mo addition is able to make transformation line of acicular ferrite of CCT curves right shift and promotes formation of acieular ferrite.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2009年第5期96-100,共5页
Transactions of Materials and Heat Treatment
基金
国家科技支撑计划项目(2006BAE03A15)
