V、N微合金化低碳贝氏体钢的成分设计与组织特征
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摘要
本文研究了V、N微合金化低碳贝氏体钢的合金成分设计及其连续冷却相变特性,设计并冶炼了七炉低碳贝氏体钢,利用Formastor-FⅡ全自动相变仪上测定其连续冷却转变曲线;并且为了提高V、N微合金化低碳贝氏体钢的综合力学性能,细化相变组织,运用Gleeble-1500D热模拟试验设备进行一系列的热模拟实验,利用金相显微镜、扫描电镜、透射电子显微镜进行组织结构及析出物的观察;最后对V、N微合金化低碳贝氏体钢进行轧制,测定实验钢的力学性能,得到下述主要研究结果:
     在含V的低碳贝氏体钢中,加入微量的B元素,可使实验钢与Nb-B系低碳贝氏体钢类似,即在空冷的冷速下便可以得到完全的贝氏体组织;而去掉元素B后,含V低碳贝氏体钢的贝氏体淬透性降低,生成贝氏体组织的临界冷却速度升高。而向钢中加入合金元素Mo、Cr可以提高实验钢的贝氏体淬透性,降低生成贝氏体组织的临界冷速和贝氏体转变温度,提高钢的硬度,但相比之下,Mo的作用要优于Cr。
     实验钢经过热模拟变形处理后发现,随着变形量的增大,板条尺寸减小,组织明显细化;而实验钢经变形后,保温时间的变化也将影响相变组织的尺寸,保温时间在120s时,板条束的细化效果较好;另外在不同温度下变形后直接水冷试样的板条组织均较粗大,但经保温弛豫120s处理后,贝氏体束的尺寸明显变小。变形后经保温弛豫处理的试样中分布着许多V(C,N)析出粒子,这些析出物有的在原奥氏体晶界处形成,在钢中主要起到限制高温奥氏体长大的作用,还有些析出粒子在晶粒内部形成,在冷却过程中可以促进贝氏体的形核,细化板条组织。
     在低碳贝氏体钢中加入V、N元素,冷却后得到的贝氏体板条尺寸明显减小,且屈服强度要比未加V、N的实验钢高出90MPa,维氏硬度也达到了300HV。对于V-N微合金化低碳贝氏体钢,终轧后空冷弛豫25s处理的实验钢,其贝氏体板条尺寸要明显小于未弛豫的试样,且其轧后及回火后的强韧性均要优于未弛豫的实验钢。经终轧弛豫后的实验钢中有较多的V(C,N)析出粒子形成,促进了针状铁素体的形成;通过再结晶细化奥氏体晶粒以及针状铁素体对原奥氏体晶粒的分割作用,细化了组织,改善钢的综合性能。
In this paper, the composition design and transformation characterstics during continuous cooling of vanadium and nitrogen microalloyed low carbon bainitic steels were researched. Seven experimental steels were prepared and CCT curves were determined on Formastor-F II automatic transformation measuring apparatus. For increasing comprehensive performance and refining microstructures of vanadium and nitrogen microalloyed low carbon bainitic steels, thermal simulation experiments were tested by Gleeble-1500. And microstructures and precipitates were observed by Microscope, SEM and TEM. Finally experimental steels were hot rolled and mechanical properties were tested. Results as follows:
     Similar to Nb-B steel, the steel containing V and B can get fully bainitic structures at the air cooling rate. Removing B from low carbon bainitic steel containing V leads to lower bainite hardenability. And adding Mo and Cr into these steels can improve bainite hardenability, lower critical cooling rate VC-95%B, decrease the bainite transformation temperature and increase hardness.But compared to Cr, Mo is the more effective element to promote bainite transformation.
     It is found from the results of thermal simulation that the size of laths is reduced and microstructures are refined with increasing deformation. The holding time after deformation will affect the size of microstructures and the size of lath is better refined when the holding time is 120s. The microstructures were thick in samples with different deformation temperature, but after holding 120s after deformation the size of bainite laths is reduced. In addition, these are V(C,N) precipitates in samples with holding, and the precipitates formed in grain boundries can inhibit grain growing and precipitates formed in the grain can improve strength and promote the nucleation of bainite, refine microstructures.
     The size of bainite laths is smaller after cooling in low carbon steel contain vanadium and nitrogen, and yield strength is 90MPa higher than the steel without vanadium and nitrogen. Also the size of bainite laths is smaller in low carbon steel contain vanadium and nitrogen with relaxation 25s after hot rolled than the steel without relaxation, and comprehensive performance is superior to the steel without relaxation. There are some V(C,N) precipitates which can promote the formation of acicular ferrite in the steel with relaxation 25s. The effect of recystallization and acicular ferrite partitioning on austenite grain can refine microstructure and improve mechanical properties.
引文
[1]李纪委,刘庆锁,超低碳贝氏体钢的研究现状,天津理工大学学报,2008,24(1):56-59
    [2]贺信莱,尚成嘉等,高性能低碳贝氏体钢-成分、工艺、组织、性能与应用.北京:-冶金工业出版社,2008
    [3]Bardgett W E, Reeve L. Mechanical Properties of Low-carbon, Low-alloy Steels Containing Boron. Iron and Steel Inst.,1949,163:277-294
    [4]Bardgett W E, Reeve L. High-Strength Weldable Steel. Iron Steel,1954,27:479-485
    [5]Bardgett W E, Reeve L. High-Strength Weldable Steel. Iron Steel,1954,27:514-518
    [6]McEvily A J, et al.In:Transformation and hardenability in steel, Climax Molybdenum Co.Ann.Abor,1967
    [7]小指军夫,李伏桃等译,控制轧制控制冷却-改善材质的轧制技术发展.北京:冶金工业出版社,2002
    [8]Krishnadev M R, et al. Strong Tough HSLA Steels Via Processing and Heat Treating of Cu-Ni-Nb, and Cu-Ti-B Composition. Journal of Engineering Materials and Technology,1981,103(3):207-211
    [9]Mei P R, Gorni A A. Austenite transformation and age hardening of HSLA-80 and ULCB steels. Journal of Materials Processing Technology, Holanda,2004,155-156:1513-1518
    [10]Gagliano, M S. Ph.D.Thesis, Northwestern University,2002
    [11]Gagliano, M S. Fine M E.Precipitation Kinetics of Niobium Carbide and Copper in a Low Carbon. Chromium-free Steel, Calphad (UK),2001,25 (2):207-216
    [12]陈忠伟,张玉柱,杨林浩,低碳贝氏体钢的研究现状与发展前景,材料导报,2006,20(10):84-86
    [13]方鸿生,郑燕康,黄进峰,我国贝氏体钢的前景,金属热处理,1998,(7):11
    [14]张志宏,陈良,高强度低碳贝氏体钢DB590的试制,武钢技术,2000,38 (2):14
    [15]周桂峰,文慕冰,李平和,超低碳贝氏体钢ULCB600组织结构及性能的研究,钢铁,2000,35(12):47-50
    [16]赵志平,康永林,丛津功,HQ590DB超低碳贝氏体钢中厚板的研制,特殊钢,2005,26(1):52-55
    [17]贺信莱,尚成嘉,杨善武等,高性能低碳贝氏体钢的组织细化技术及其应用,金属热处理,2007,32(12):1-10
    [18]尚成嘉,王学敏,杨善武等,高强度低碳贝氏体钢的工艺与组织细化,金属学报,2003,39(10):1019-1024
    [19]张朝生,日本超低碳贝氏体H型钢的开发,轧钢,2002,19(5):40-41
    [20]Hisata M, Miyake T, Kawabata F.420MpaYield Strength Steel Plate with Superior Fracture Toughness for Arctic Offshore Structures. Kawasaki Steel Technical Report,1998,30(3):142-147
    [21]杨万忠,新型高性能钢的应用,国外桥梁,1999(3):68-70
    [22]战东平,姜周华,王文忠,高洁净度管线钢中元素的作用与控制,钢铁,2001,36(6):67-70.
    [23]Mehl R F. Hardenability of Alloy Steels. ASM, Metals Park,1939:1
    [24]Atlas for Bainitic Microstructures, vol.1, ISIJ, Tokyo,1992
    [25]G. Krauss, S.W. Thompson. Ferrite Microstructure in Continuously Cooled Low-and-Ultralow-Carbon Steels, ISIJ International,1995,35(8):937
    [26]Shanmugam S, et al.Effect of Cooling Rate on the Microstructure and Mechanical Properties of Nb-microalloyed Steels.Materials Science and Engineering,2007,460-461:335
    [27]Jun H J, et al.Effects of Deformation and Boron on Microstructure and Continuous Cooling Transformation in Low Carbon HSLA Steels.Matreials Science and Engineering,2006,422:157
    [28]Phelan D, Stanford N,Dippenaar R.In Situ Observations of Widmanst Atten Ferrite Formation in a Low-carbon Steel.Materials Science and Engineering, 2005,407:127
    [29]Araki T. Microstructural Aspects of Bainitic and Bannite-Like Ferritic Structures of Continuously cooled Low Carbon Steels Materials, Trans JIM,1991,32(8): 729.
    [30]Sharma Udit, Ivey Douglas G. Microstructure of Micro-alloyed Line pipe Steels, ASME,2000,1:193.
    [31]Afaganis Alex J. Development and Production of Large Diameter High Toughness Gr550(X80) Line Pipe at Stelco, ASME,1998,234
    [32]K. Fujiwara, S. Okaguchi. Morphology and mechanical properties of bainitic steels deformed in unrecrystallized austenite reigon, Mater Sci Forum,1998,284: 271.
    [33]Pan T,et al.Kinetics and Mechanisms of Intragranular Ferrite Nucleation on Non-metallic Inclusions in Low Carbon Steels.Materials Science and Engineering,2006,438-440:1128
    [34]Wang J P, Yang Z G, Bai B Z, Fang H S. Grain Refinement and Microstructural Evolution of Grain Boundary Allotriomorphic Ferrite/granular Bainite Steel after Prior Austenite Deformation. Materials Science and Engineering,2004,369: 112
    [35]Wang X M, Shang C J, Yang S W, He X L, Liu X Y. The refinement technology for bainite and its application. Materials Science and Engineering,2006, 438-440:162
    [36]王有铭,李曼云,韦光,钢材的控制轧制和控制冷却.冶金工业出版社.2009
    [37]T. Siwecki, B. Hutchinson and S. Zajac. Recrystallization Controlled Rolling of HSLA Steels, In:Pittsburgh, PA. Microalloying-95, Warrendale,1995,197-211.
    [38]T. Siwecki and G. Engberg, Recrystallization Controlled Rolling of Steels, Thermo-Mechanical Processing in Theory, Modelling & Practice, ASM Intern, 1997,121-144.
    [39]尚成嘉,杨善武,王学敏,贺信莱,北京科技大学学报,2002;24:129-135
    [40]齐俊杰,黄运华,张跃,微合金化钢.北京.冶金工业出版社.2006
    [41]R.兰纳伯格著.杨才福,柳书平,张永权编译,钒在微合金钢中的作用,北京:钢铁研究总院,2000.
    [42]孙邦明,张永权等,V-N微合金化钢筋中钒的析出行为,钢铁,2001,36(2)
    [43]杨才福,张永权,祖荣祥等,钒氮微合金化钢的开发与应用.北京:钢铁研 究总院
    [44]张永权,杨才福,柳书平等,经济型建筑用Ⅲ级钢筋的研究,钢铁,2000,35(1):43-46
    [45]潘涛,杨才福,龚维幂,张永权,V(C,N)在奥氏体中析出的动力学行为及其对晶粒细化的作用,钢铁研究学报(增刊),2005,17:96-101
    [46]杜江,尹桂全,杨才福,苏航,V-N微合金化超低碳贝氏体钢相变特征,安徽工业大学学报,2007,24(4):369-373
    [47]T. Siwecki, J. Eliasson, R. Lagneborg,B. Hutchinson.Vanadium Microalloyed Bainitic Hot Strip Steels. Technical Report, Swerea-KIMAB,2009-09
    [48]李培松,肖丽俊,谢植,低碳钢中AlN和BN竞相析出热力学分析,钢铁研究学报,2009,21(5):16-19
    [49]龚维幂,杨才福,张永权等,钒氮钢中铁素体等温形核规律的试验研究,钢铁,2005,40(10):63-67
    [50]杨善武,贺信莱,硼在超低碳钢铁素体相变中的行为,金属学报,1999,35(1):23-26.
    [51]P.Cizek, B.P.Wynne, C.H.J.Davies, et al. Effect of composition and austenite deformation on the transformation characteristics of low carbon and ultralow-carbon microalloyed steels. Metallurgical and materials transactions A, 2002(33A):1331-1349.
    [52]周乐育,刘雅政,方圆等,铬对C-Si-Mn-Nb铁素体贝氏体双相钢相变规律的影响,钢铁研究学报,2009,21(7):38-41.
    [53]孙本茂,王执福,公志光,铬和钼对奥氏体-贝氏体钢的组织和性能的影响,铸造,1996,1:25-27
    [54]方芳.C、N对V(C,N)析出行为的影响:[博士学位论文].北京,钢铁研究总院,2009
    [55]赵新,荆天辅,高聿,板条马氏体大变形轧制工艺的晶粒细化机制,钢铁研究学报,2004,16(6):69-73
    [56]刘清友,候豁然,微合金钢超细组织的控制轧制,钢铁研究学报,2000,12(6):29-32
    [57]董毅,时晓光,韩斌,终轧温度对热轧细晶双相钢组织与性能的影响,金属热处理,2011,36(1):64-67
    [58]李曼云,孙本荣,钢的控制轧制和控制冷却技术手册.北京:冶金工艺出版社,1992
    [59]Calos Garcia-mateo, Calos Capdevila, Francisca G.Caballero, Calos de Andres. Influence of V precipitates on acicular ferrite transformation Part 1:The role of nitrogen. ISIJ Internation,2008,48 (9):1270-1275
    [60]Shang Cheng-jia, Wang Xue-min, He Xin-lai, et. Stability of ultra-fine microstructures during tempering. Journal of University of Science and Technology, Beijing,2001,8 (3):119-122
    [61]Calos Garcia-mateo, Calos Capdevila, Francisca G.Caballero, Calos de Andres. Influence of V precipitates on acicular ferrite transformation Part 2: Transformation Kinetics. ISIJ Internation,2008,48 (9):1276-1279
    [62]K.He, D.V.Edmonds. Formation of acicular ferrite and influence of vanadium alloying. Material Science and Technology,2002,18:289-296

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