Ti,Nb,V复合碳氮化物点阵常数的测定

本文介绍了用CBED法和能谱法同时测量不同颗粒尺寸的Ti,Nb,V析出相的点阵常数和化学成分。CBED法的测量精度可达万分之二。它们分别获得颗粒的点阵常数值,误差小于1％。在测量中发现:在Nb-V钢中浓度比(C_(Nb)/C_V)和点阵常数随着析出颗粒尺寸的减小而递减。但是,在Ti-V-Nb钢中Ti,Nb和V的析出量和点阵常数与析出颗粒尺寸的关系无规律。     

钢中(Nb,V)碳氮化物应变诱导析出动力学

利用压力膨胀仪和萃取复型法研究了Nb—V微合金化钢中(Nb.V)CN析出相在四种压下量(0,10,30和50％)和三种温度(1100,1000和850℃)下的等温析出规律,获得了四种类型析出动力学曲线。     

微合金钢碳氮化物的应变诱导析出研究

在Gleeble3500热模拟机上采用应力松弛法,研究了一种微合金非调质油井管用钢在600～ 950℃内含钒碳氮化物的应变诱导析出行为.结果表明:该实验钢的PTT(析出-温度-时间)曲线具有双“C”特征,碳氮化物析出孕育期最短的温度分别约为850℃和650℃.析出相形貌主要为球形.     

松弛法研究微合金钢碳氮化物的应变诱导析出行为

在Ｇｌｅｅｂｌｅ上采用应力松弛方法,研究了一种ＮｂＴｉＶ微合金化钢奥氏尖变诱导析出行为,结果表明：实验钢的沉淀析出ＰＴＴ曲线最典型的“Ｃ”曲线形状,沉淀发生具有一个最快析出温度,大致９００－９２０℃,奥氏体预变形加速沉淀析出过程的进行,使ＰＴＴ曲线向左上方偏移,奥氏体中的沉淀相形貌有球形和方形两种,其中方形沉淀相是均热过程中的未熔质点,以ＴｉＮ为主,球形深沉是应变诱导析出相。     

贝氏体型非调质钢微合金碳氮化物的应变诱导析出

在Gleeple1500热模拟实验机上采用应力松驰法确定了一种贝氏体型SBL非调质钢微合金碳氮化物的沉淀分析行为，并讨论形变量、温度等参数的影响作用。     

微合金元素Nb,Mo在应变诱导析出过程中的相互作用

运用热模拟技术和透射电子显微镜,研究了C-Mo、C-Ti-Mo和C-Nb-Mo三种简单成分钢奥氏体变形后松弛过程中微合金元素Nb、Mo在析出物中的相瓦作用.结果表明:在850℃变形后松弛1000 s.三种钢均保持了奥氏体状态,但C-Ti-Mo和C-Nb-Mo钢有析出发生,能谱分析显示析出颗粒分别是Ti(C,N)和含Mo的Nb(C,N).微合金元素Mo与Nb有较强的相互作用,在Nb(C,N)析出后,Mo可能溶入Nb(C,N)的析出颗粒之中.     

热连轧过程复合微合金碳氮化物析出的定量计算

以微合金元素的析出热力学和析出动力学为基础,针对Fe-Nb-V-Ti-Al-C-N合金系,定量计算了热连轧过程中(Nb,V,Ti)(C,N)和AlN在奥氏体中的析出行为,并进一步分析了热轧制温度对析出行为的影响。计算结果表明,对所研究的钢种成分和工艺条件,在加热过程中(Nb,V,Ti)(C,N)就已经析出,在粗轧阶段,(Nb,V,Ti)(C,N)析出粒子平均半径逐渐减小,在精轧阶段,(Nb,V,Ti)(C,N)基本达到平衡析出量,终轧后析出粒子平均半径保持在23 nm左右。轧制时的热变形增大了形核率,促进了析出,使析出粒子的平均半径减小。随加热和轧制温度的降低,(Nb,V,Ti)(C,N)的析出量有所增加,粒子平均半径减小。     

三维原子探针对铌微合金化钢碳氮化物的析出研究

利用三维原子探针（3DAP）可以对不同元素的原子逐个进行分析,并给出纳米空间中不同元素原子的三维分布图形,分辨率接近原子尺度的优越性能,对含铌轿车横梁钢中的碳氮化物进行分析,结果表明,铌微合金化钢中存在尺寸为几个纳米大小的铌碳氮化物析出物,析出物呈薄片状,同时,铌碳氮化物在铁索体中析出是随机的。     

Nb微合金化E36造船钢板控轧控冷实验研究

通过对Ｎｂ微合金化Ｅ３６高强度船体结构钢板的控轧控冷实验研究,分析了控轧控冷工艺对钢力学性能、晶粒组织及析出物的影响,并对控轧控冷Ｎｂ微合金化钢的强化机理进行了探讨。得出所研究钢的最优终轧温度和冷却速度分别为８１０℃和２℃／ｓ,给出了钢板屈服强度与结晶组织、附加屈服应力与析出相粒子之间的关系。     

X80管线钢碳氮化物析出热力学研究

采用规则溶液亚点阵模型建立了Fe-Nb-Ti-Al-C-N系统,分析了不同温度条件下,X80管线钢中碳氮化物析出热力学行为。经实验验证,用此模型来预测管线钢中析出物的热力学析出行为具有良好的精度。     

STRAIN-INDUCED ISOTHERMAL PRECIPITATION OF Nb,V AND Ti CARBONITRIDES IN MICROALLOYED STEELS DURING CONTROLLED ROLLING

The strain-induced isothermal precipitation and the law of coarsening of Nb,V and Ticarbonitrides in Nb-steel.V-steel.Nb-V steel and Ti-V-Nb steel have been investigatedsystematically by means of STEM,EDAX,a new extraction replica technique and the quanti-tative phase analyses method.     

KINETICS OF STRAIN-INDUCED PRECIPITATION OF (Nb,V) CARBONITRIDE IN A MICROALLOYED STEEL

The kinetics of the isothermal precipitation of(Nb,V)CN in Nb-V alloys has been investi-gated by using the Formastor-press simulator and the extraction replica method.Under fourdeformation amounts(0,10,30,50%)and three temperatures(1100,1000,850℃),four types of kinetic curves were found.     

MODELING OF ISOTHERMAL PRECIPITATION KINETICS IN HSLA STEELS AND ITS APPLICATION

1.IntroductionMicroalloying elements, such as Nb, Ti and V in HSLA steels precipitate during hot-rolling pro-cesses, which plays an important role in determining mechanical properties of HSLA steels[1].In order to model the precipitation behavior, many quantitive models[2-8] have been proposed. These models, however, can only be applied to single microalloyed steels. As temperature decreases continu-ously during hot deformation processes, isothermal data can not be used directly to predic…     

EFFECT OF COPPER AND BORON CONTENT ON STRAIN-INDUCED Nb(C,N) PRECIPITATION IN ULCB STEELS AT HOT DEFORMATION TEMPERATURE

1.IntroductionUltra-LowCarbonBainitic(ULCB)steels,whichhaveall-purposehighstrengthandtoughness,havebeendevelopedformorerecenttwentyyearsaroundtheworld.Thekineticsofstrain-inducedprecipitationoccurredinthiskindofsteelhavebeeninvestigatedindepth,anditisfoundthatmostoftheprecipitation-time-temperature(PPT)curvesareofC-shapedif--6].Theresearchesdealingwiththeinfluenceofalloyingelementsontheprecipitationalsohavebroughtoutsomevaluableresults.Heetal[7]reportedthatboroninNbmicroalloyedULCBsteel…     

微合金钢中TiN的析出规律研究

通过热力学计算及实验,研究了含Ｔｉ微合金钢在液态及凝过程中ＴｉＮ的析出规律,研究表明,通过调整微合金钢中Ｎ和Ｔｉ含量,可以控制ＴｉＮ的析出时机和形态,减小其对钢性能的有害影响;还探讨了利用液态析出细小,弥散的ＴｉＮ作为钢液蝗形核中心,以细化态组织,得到等轴细晶的可能性。     

LATTICE PARAMETERS OF COMPLEX CARBONITRIDE CONTAINING Ti,Nb AND V

The lattice constants and chemical composition of Ti,Nb and V precipitates with differentparticle sizes have been measured hy means of CBED and EDAX.It was obtained that theconcentration ratio Of Nb and V,C_(Nb)/C_V,and the lattice constants in the Nb-V steel de-crease with the decrease of the particle size of the precipitates,but there is no regularity fortattice constant of Ti,N b and V precipitate against their particle size in the Ti-V-Nb steel.     

MODELING OF ISOTHERMAL PRECIPrrATION KINETICS IN HSLA STEELS AND ITS APPLICATION

Microalloying elements in high-strength low-alloy steels, such as Nb, Ti and V, precipitate during hot-rolling processes. On the basis of classical theory of nucleation and growth, quantitative modeling of isothermal precipitation was developed, which was tested by the stress relaxation method, the calculated precipitation-time-temperature curve is in good agreements with the measured results, then the model was applied to predict the precipitation behavior during continuous cooling.     

钢中铌钒碳氮化合物的析出及其稳定性分析

采用双亚点阵模型对结构钢和合金工具钢中钒、铌的碳化物和氮化物析出时的竞争及稳定性作了热力学分析。举例指出在铬钒系结构钢中,高温时的析出是以铌的碳氮化合物为主,在低温时以碳化钒为主。在铬钼硅钒系合工钢中,无论在何种温度下,均以碳化钒的析出为主。