钒氮微合金化对汽车用热轧钢板组织与力学性能的影响  

Effect of V-N microalloying on microstructure and mechanical properties of hot-rolled steel plate for automobile

作　　者：刘建 李月丽[1,2,3] LIU Jian;LI Yue-li(College of Mechanical Engineering,Tongling University,Tongling 244000,China;Key Laboratory of Construction Hydraulic Robots of Anhui Higher Education Institutes,Tongling University,Tongling 244000,China;Key Laboratory of Additive Manufacturing of Tongling City,Tongling University,Tongling 244000,China)

机构地区：[1]铜陵学院机械工程学院,安徽铜陵244000 [2]铜陵学院工程液压机器人安徽普通高校重点实验室,安徽铜陵244000 [3]铜陵学院铜陵市增材制造重点实验室,安徽铜陵244000

出　　处：《塑性工程学报》2022年第3期150-156,共7页Journal of Plasticity Engineering

基　　金：安徽省高校自然科学研究项目(KJ2013B301);安徽省高校自然科学重点研究项目(KJ2019A0710)。

摘　　要：通过向钢中添加VN12合金冶炼了5种不同钒、氮含量的试验钢,将冶炼后的钢锭先锻成板坯,再热轧成7 mm厚的钢板。经化学成分对比分析,试验钢的平均钒/氮比约为4.42,即每增加0.01%的钒,可增氮约0.00226%。借助光学显微镜和透射电镜分析了试验钢的显微组织和第二相的析出情况,结果表明,试验钢的组织均由铁素体和珠光体组成,钒、氮含量的增加明显细化了铁素体晶粒,促进了大量第二相细小颗粒的析出,铁素体晶粒尺寸由9.42μm减小至4.62μm。通过拉伸和冲击试验,分析了试验钢的力学性能,对试验钢的强化机制进行了研究,结果表明,钒含量由0.024%增加至0.140%时,试验钢的屈服强度和抗拉强度分别提高了202和165 MPa,保持了良好的韧塑性;钒氮微合金化钢板的主要强化方式为细晶强化和析出强化,细晶强化对屈服强度的贡献大于析出强化,但二者对屈服强度增量的贡献随钒和氮含量的不同而有所差异,钒含量低于0.1%时,析出强化起主导作用,钒含量高于0.1%时,细晶强化起主导作用。Five kinds of test steels with different vanadium and nitrogen contents were smelted by adding VN12 alloy to steel.The ingots were forged into slabs and then hot-rolled into steel plate with thickness of 7 mm.Through the comparison and analysis of chemical composition,the average V/N ratio of test steels is about 4.42,that is,the nitrogen can be increased by 0.00226% when the vanadium is increased by 0.01%.The microstructure and second phase precipitation of test steels were analyzed by means of optical microscope and transmission electron microscope.The results show that the microstructure of test steels is composed of ferrite and pearlite.The increase of vanadium and nitrogen content significantly refines the ferrite grains,promotes the precipitation of a large number of fine particles of the second phase,and the grain size of ferrite decreases from 9.42 μm to 4.62 μm.Through tensile and impact tests,the mechanical properties of test steels were analyzed,and the strengthening mechanism of test steels was studied.The results show that when the vanadium content increases from 0.024% to 0.140%,the yield strength and tensile strength of test steels increase by 202 and 165 MPa,respectively,and good toughness and plasticity are maintained.The main strengthening modes of V-N microalloyed steel plate are fine grain strengthening and precipitation strengthening,and the contribution of fine grain strengthening to yield strength is greater than that of precipitation strengthening.However,their contribution to yield strength increment varies with the content of vanadium and nitrogen.Precipitation strengthening plays a leading role when the content of vanadium is lower than 0.1%,and fine grain strengthening plays a leading role when the content of vanadium is higher than 0.1%.

关 键 词：钒氮微合金化 热轧钢板 组织 力学性能 强化机制 

分 类 号：TG142[一般工业技术—材料科学与工程]