微合金化铌钒对高碳钢组织转变影响

Effect of Nb-V Microalloying on Phase Transformation Behavior of High Carbon Steel

研究了四种成分铌钒微合金化(Nb0-0.072%,V 0.09%-0.12%)高碳钢(0.70%~0.73%C)在900~1200 ℃的加热温度下的奥氏体晶粒长大规律,并采用热模拟试验机测定了连续冷却相转变行为,利用金相显微镜、硬度仪等研究了冷却速度对金相组织、硬度等指标的影响。结果表明:Nb和V含量增加可细化奥氏体晶粒尺寸,降低高温晶粒长大倾向,并且CCT曲线转变区向右下方移动,贝氏体和马氏体形成和结束点向低冷速方向扩大,结束点由8℃/s降低至3℃/s,样品硬度也随之增加。

Effect of Nb-V addition(Nb 0~0.072%,V 0.09%-0.12%)on austenite grain growth behavior of high-carbon steels(0.70%~0.73%C)in 900~1200℃is studied,and the continuously cooled transformed curves of steel are investigated by Gleeble-3800 thermal-mechanical simulator,and the influence of cooling rates on microstructure and hardness of steel is investigated using optical microscope and hardness tester.The results show that with increasing Nb and V content in steel the austenite grain size is fining and grain grown tendency of the steel is smaller,and CCT curves move to the lower right,and the formation and end point of bainite and martensite shift towards low cooling rate,the end point decreases from 8℃/s to 3℃/s,and the hardness of sample increase with increase of Nb/V content.