200mm×200mm连铸坯连轧Φ100mm 42CrMo钢三维有限元模拟

采用MSC.Marc有限元模拟软件,针对200 mm×200 mm连铸方坯连轧Φ100 mm 42CrMo圆钢工艺过程进行三维热力耦合模拟仿真。因圆角在孔型中塑性应变较大且变形由表及里逐渐深入,因此对断面采用网格偏差划分方法以细分表层及圆角区域单元。根据连轧过程应力场、应变场和温度分布及轧制力和轧制力矩变化特点,得出合金钢轧制时圆角易出现裂纹的重要原因是该区域总等效塑性应变、等效应力和温降较大。机架间及轧后断面尺寸实测值与模拟值相符合。     

AISI1008圆钢混晶原因分析及有限元模拟和工艺改进

在棒材线轧制锻造爪机用AISI1008钢时,出现混晶现象,Φ50 mm棒材边缘铁素体晶粒度3级,1/2半径及心部铁素体晶粒度8级,通过对钢材进行金相组织及电镜检验,对轧制过程温度及等效应变利用Deform软件进行有限元模拟,发现造成圆钢边缘晶粒粗大的原因与终轧温度过低及轧制等效应变大且分布不均有关,将终轧温度由原820℃提高至880℃,成功改善了圆钢横截面混晶现象。     

精轧开轧温度对Q235B连轧过程的影响规律研究

本文基于ABAQUS/Explicit平台建立了Q235B热连轧的三维弹塑性热力耦合有限元模型,分析了精轧开轧温度对成形环件的应变和温度分布不均匀性以及轧制力能参数的影响规律,同时进行了现场轧制实验的验证。结果表明:随着开轧温度的增加,轧件的温度分布愈来愈不均匀,等效应变分布愈来愈均匀,轧件中部的等效应变增大,轧制力、轧制力矩逐渐减小。     

Mn-Cr系齿轮钢热变形行为研究

采用Gleeble 1500热模拟试验机研究了一种Mn-Cr系齿轮钢的动静态再结晶行为.试验结果表明在给定应变速率1/s下,试验钢存在3种类型的应力-应变曲线变形温度在1 100℃以上时,变形奥氏体发生动态再结晶;1 000～1 050℃之间时只发生动态回复过程;950℃以下时不发生动态再结晶和动态回复.     

高温形变参数对4J32超因瓦合金组织演变的影响

使用热模拟压缩试验仪器,设置850～1 150℃不同应变温度和0.1～10 s^-1应变速率等热变形参数进行试验,通过金相显微镜、热模拟试验等设备对合金进行组织形貌表征,结合热模拟压缩试验应力应变曲线及合金组织形貌进行分析,系统性研究4J32超因瓦合金(Fe-32Ni-4Co)在850～1 150℃高温热变形行为及组织形貌演变过程。研究发现,4J32超因瓦合金在900℃以下热变形过程不发生动态再结晶,且合金中存在大量的变形晶粒组织。当热变形温度大于1 050℃时,合金开始发生动态再结晶,且应变速率越快其动态再结晶程度越高。研究结果表明,超因瓦合金最优的热变形温度>1 100℃,应变速率为10 s^-1。     

精轧轧制参数对IF钢奥氏体再结晶的影响

对含有Ti,Nb,Ti—Nb的三种无间隙原子钢(IF钢),利用多道次扭转试验,研究了它们总的精轧变形量(从2.1～3.2)和精轧开轧温度(从990～930℃)的影响。这些试验的应变速率为2s~-1。在精轧中,静态再结晶是造成早期轧制阶段轧制间隙期间高度软化的原因。在后来的轧制阶段,动态再结晶的出现取决于钢的化学成分、精轧总变形量和精轧温度。lF钢的临界温度是模拟粗轧工艺确定的。以相同的轧制工艺为条件.Nb固定钢晶粒最细,反之,Ti固定钢铁素体晶拉最大。由于精轧的间隙时间(1～2s)比粗轧的间隙时间要短得多,所以精轧时IF钢呈现出高的未再结晶温度。     

Custom 450高强度不锈钢的动态再结晶行为

为了探究Custom 450钢的动态再结晶行为,采用Gleeble-3800热模拟试验机,在变形温度为1 050～1 200℃和应变速率为0.01～10 s~(-1)的变形条件下开展了单道次等温压缩试验。研究结果显示,在变形温度为1 050～1 200℃和应变速率为1.0～10 s~(-1)的变形范围内,钢虽发生了完全的动态再结晶,但应力应变曲线未表现出明显的应力峰值;钢的动态再结晶的晶粒尺寸随着变形温度的升高和应变速率的降低逐渐增大,当应变速率为0.01 s~(-1)时,动态再结晶晶粒发生长大。采用双曲正弦函数构建了Cutom 450钢的热变形方程,并建立了钢的动态再结晶动力学、临界应变、峰值应变及动态再结晶晶粒尺寸与Zener-Holloman参数的定量关系。     

315MPa级船板钢热变形行为的研究

为了制定船板钢的控制轧制工艺,采用MMS-300热/力模拟试验机研究了315 MPa级船板钢的热变形行为。结果表明:在高温、低速率、大变形量条件下,315 MPa级船板钢易于发生动态再结晶;随着变形间隔时间的增长,未再结晶温度逐渐降低。如果采用高变形温度、低应变速率和大变形量变形,通过动态再结晶可细化奥氏体晶粒;同时,二阶段开轧温度应低于932℃,通过变形带的生成可进一步细化奥氏体晶粒。     

高Nb--TiAl合金叶片锻造模拟

采用Deform-3D有限元软件模拟β-γ高Nb-Ti Al合金叶片等温锻造,分析等效应变场、等效应力场与温度场的分布.叶片等温锻造中叶身与榫头的等效应变分布均匀,随着上模具压下速度的增大和预热温度的升高,变形过程中等效应力降低,有利于动态再结晶的发生;上模具压下速度在1.0~1.5 mm·s-1、预热温度在1250~1300℃有利于提高β-γ高Nb-Ti Al合金叶片锻件的质量.      

楔横轧成形25CrMo4厚壁空心轴件的不圆度分析

机械结构轻量化的主要途径是在结构上采用空心轴.近年来, 采用楔横轧带芯棒轧制空心轴类件的工艺得到了较广泛的关注.厚壁空心轴类件在楔横轧轧制过程中易发生“失圆”现象.本文通过热压缩实验研究了25CrMo4合金钢在楔横轧变形条件下热变形行为, 获得其真应力-应变曲线.在此基础上, 基于Deform-3D有限元软件, 建立25CrMo4厚壁空心轴楔横轧有限元仿真模型, 分析厚壁空心轴楔横轧成形机理, 研究得出断面收缩率、成形角、展宽角对轧件不圆度的影响规律: 断面收缩率增大, 不圆度减小; 成形角增大不圆度减小, 轧制温度越高减小趋势越明显; 展宽角增大不圆度增大, 提高轧制温度抑制增大趋势.选取部分工艺参数进行楔横轧验证实验, 对比了有限元仿真结果和实验结果, 表明有限元仿真模型预测精度较高.      

Explicit Dynamic FEM Analysis of Multipass Vertical-Horizontal Rolling

Three passes of plate rolling during vertical-horizontal rolling process are simulated with explicit dynamic finite element method and updating geometric method. The equivalent strain and stress fields, and shape change at the head and tail of slab during rolling are obtained. The calculated result of the shape at the head and tail of slab is in good agreement with the measured one. The explicit dynamic finite element method and updating geometric method can be used effectively to analyze the multipass vertical-horizontal （V-H） rolling process.     

20CrMnTi齿轮钢棒材热连轧有限元模拟

通过对棒材热连轧过程的分析,建立了20CrMnTi钢800~1150℃,变形量0~0.8,应变速率0~3 s^-1的Hensel-Spittel流变应力模型;利用LARSTRAN/SHAPE有限元软件模拟了20CrMnTi从200 mm×200 mm的方坯经8道次连轧为Φ90 mm圆棒的过程,分析了轧件在圆弧侧壁的圆孔型和直线侧壁的圆孔型下轧制过程中的应力场、应变场、温度场和轧制力及力矩的变化情况。模拟结果表明,轧件圆角部位等效应力、等效应变较大且温度较低,容易出现轧制质量缺陷;圆弧侧壁的圆孔型轧制圆钢时的精度略高于直线侧壁的圆孔型。     

CSP连轧过程金属变形的热力耦合模拟分析

借助Marc商用软件,采用弹塑性大变形热力耦合有限元法(FEM),对包钢生产的1 500 mm×68mm薄板坯CSP(紧凑式带材生产)轧制第一道次的热轧过程进行了模拟。分析了变形区内轧材等效应力场、应变场及应变速率的分布和变化规律。结果表明在轧件变形区内,等效应力沿轧制方向逐渐增大,在中性面附近达到最大值(95.20 MPa),后又逐渐减少;等效应变亦沿轧制方向逐渐增大,在轧件出口处达到最大值(0.70);在轧件入口端表面附近等效应变速率有最大值,为20.74 s^-1。模拟计算的轧制力为22 203 kN,现场测得的轧制力为22 239 kN,预测误差为0.16%。     

钢板桩轧制过程充型模拟及轧制力有限元分析

采用二辊可逆式轧机和万能轧机组轧制钢板桩(/%:0.12～0.22C、0.15～0.55Si、0.80～1,50Mn)。通过热模拟试验得出该钢在980～1 030℃、变形速率0.5～5.0-1 时的应力-应变曲线。借助ABAQUS软件,采用弹塑性有限元法对钢板桩轧制过程进行了三维热力耦合模拟。针对生产中出现的轧机过载问题,分析了轧制过程各道次的轧制力,通过改变相关道次孔型辊缝改善了充型和降低轧制力。     

Mathematical Model of Microstructure Evolution of X60 Line Pipe Steel During CSP Hot Rolling

An integrated process modelling system for simulating the microstructure evolution of Nb-microalloyed HSLA steel produced in CSP hot rolling process has been developed on the basis of the microstructure simulation and mechanical properties prediction technology. 3-D thermomechanical coupled finite element models for simulating hot strip rolling have been developed and the distribution of equivalent plastic strain through the thickness direction of the rolled material by CSP roiling was obtained. Thus the distribution of temperature, strain and strain rate through the thickness of the steel stocks, as well as the microstructure evolution during hot rolling of X60 line pipe steel strip has been investigated by using the developed integrated process modelling system. In addition, the determination and op-timization of controllable process parameters during CSP hot strip rolling for the Nb-microalloyed X60 line pipe steel have been implemented, and control strategies such as adopting larger pass reduction in the first stand, arranging ap-propriate pass interval times and proper rolling speed, to reduce or eliminate mixed grain microstructure of Nb micro-alloyed strip in CSP processing have been proposed.     

Mathematical Modelling on the Microstructure Evolution of X60 Line Pipe Steel during CSP Hot Rolling

 An integrated process modelling system for simulating the microstructure evolution of Nb-microalloyed HSLA steel produced in CSP hot rolling process has been developed on the basis of the microstructure simulation and mechanical properties prediction technology. Thermo-mechanical coupled finite element models for simulating hot strip rolling have been developed and the distribution of equivalent plastic strain through the thickness direction in the rolled material of CSP rolling was carried out. Thus the distribution of temperature, strain and strain rate through the thickness of the steel stocks, as well as the microstructure evolution during hot rolling of X60 line pipe steel strip have been investigated by using the developed integrated process modelling system. In addition the determination and optimization of controllable process parameters during CSP hot strip rolling for the Nb-microalloyed X60 line pipe steel have been implemented, and control strategies such as adopting larger pass reduction in the first stand, and arranging appropriate pass interval times and proper rolling speed, to reduce or eliminate mixed-grains microstructure of Nb microalloyed strip in CSP processing have been proposed.     

Nonlinear Finite Element Analysis of Thin Strip Temper Rolling Process

 To reveal the basic deformation mechanisms under the conditions of high friction, small reduction, and long contact length in thin strip temper rolling process, an elastoplastic finite element analysis of plane strain upsetting was made based on the FEM software Marc. The results indicated that a near flat ‘zero reduction’ region was present in the center of the contact arc. The simulation results about the effect of rolling parameters on the central flat region showed that any change of increasing the rolling force could result in or enlarge the central flat region in the deformation zone. Stress distribution results illustrated that the metal was in triaxial compression state. Although the maximum and minimum principal stresses were all much larger than the yield stress of the strip, the equivalent stress became lower than that, and no further plastic strain, even a small elastic spring back occurred in the central flat region. That was the problem of ‘hydrostatic pressure’ in thin strip temper rolling.     

斜轧螺纹过程的数值模拟

对螺旋孔型斜轧螺纹过程进行了非线性有限元分析，得到了轧件内部应力－应变分布情况，为模具的设计和工艺参数的确定提供了重要依据。     

Finite Element Simulation of Hot Strip Continuous Rolling Process Coupling Microstructural Evolution

 Using the nonlinear rigid viscoplastic finite element method (FEM), a finite element simulation of the hot strip continuous rolling process was done, which completely integrates different phenomena such as the metallurgical behavior of the strip and the thermo mechanics in the strip based on the physical metallurgical microstructural evolution law. By combining with the process parameters of certain 2 050 mm hot strip rolling, an actual rolling process of low carbon steel SS400 was simulated using the FEM model. Based on the simulation results, the distributions of the strain field, the temperature field, and the microstructure were presented. Meanwhile, the simulated rolling force, temperature, and microstructure are in good agreement with the measured results.     

60 kg/m钢轨热轧过程的三维有限元模拟

采用非线性有限元软件MARC/AutoForge，通过三维弹塑性热力耦合的有限元方法模拟了重轨800-I孔的变形过程，分析了轧件上等效应力、应变场、温度场和轧制力。轧件最大变形值于帽形腰腿圆弧和两侧腿尖处，在轧件中部靠近表面区域升温最大。