管线钢X80的CCT曲线研究
Research on CCT Curve of Pipeline Steel X80
左碧强, 王 岩, 米振莉, 赵爱民
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作者单位：北京科技大学 冶金工程研究院, 北京 100083
中文关键字：管线钢X80； CCT曲线； 针状铁素体
英文关键字：pipeline steel X80; CCT curve; acicular ferrites
中文摘要：采用膨胀仪研究管线钢X80连续冷却过程中的相变规律。采用热膨胀法和金相法相结合测绘管线钢X80的CCT曲线，并研究冷却速率对组织和硬度的影响规律。实验结果表明：不同的冷却速率下实验钢的组织不同。 低冷速下，管线钢X80的组织均为多边形铁素体外加少量的珠光体；随着冷速的增加(＞3℃/s时)，多边形铁素体逐渐转变为针状铁素体；当冷速达到50 ℃/s以上时，还会出现贝氏体组织。随冷速的提高，实验钢的硬度呈逐渐上升趋势。
英文摘要：The law of phase change of pipeline steel X80 during continual cooling was studied by adopting dilatometer. The CCT curves of pipeline steel X80 were drawn by adopting dilatometer and metallographic method, and the effects of cooling rates on microstructure and hardness of the steel were studied. The experimental results show that the microstructure of the steel is different at different cooling rates. When the cooling rate is low, the microstructure of the pipeline steel X80 is mainly polygonal ferrite and little pearlite. As the cooling rate goes up (>3℃/s), the polygonal ferrite is gradually changed into acicular ferrite. As the cooling rate goes up to 50℃/s, bainite appears. The hardness of the steel turns out gradual upward trend with the increase of cooling rate.