Crystallographic texture and earing behavior analysis for different second cold reductions of double-reduction tinplate

Since the production of tinplate with non-earing properties is difficult, especially when it is produced via the double-reduction process, the optimal degree of second cold reduction is particularly important for achieving desirable drawing properties. The evolution of texture and the earing propensity of double-reduction tinplate with different extents of second reduction were investigated in this study. Optical microscopy and scanning electron microscopy were used to observe the changes in the microstructure at various extents of reduction. Two common testing methods, X-ray diffraction（XRD） and electron backscatter diffraction, were used to investigate the texture of the specimens, which revealed the effects of deformation percentage on the final texture development and the change in the grain boundary. The earing rate was determined via earing tests involving measurement of the height of any ear. The results obtained from both XRD analyses and earing tests revealed the same ideal value for the second cold reduction on the basis of the relationship between crystallographic texture and the degree of earing.

PREDICTION OF EARING IN TEXTURED ALUMINIUM SHEETS BASED ON CRYSTAL PLASTICITY

The phenomenon of earing is investigated in the present studybased on the theory of crystal plasticity with the dynamic explicityfinite element program developed. Firstly texture analysis is carriedout of rolled aluminum alloy A15052 by means of X-ray technique. Thenfrom the texture coefficients an analytical expression for theorientation distribution function (ODF) is derived making use of thecomputer algebraic language Mathematica4.0, which makes it easier todiscretize the ODF into a series of Eulerian angles repre- sentingthe distribution of lattices and further the preferred orientation(texture) of crystals of the original she- ets.

Simulation of annealing process effect on texture evolution of deep-drawing sheet Stl5

A two-dimensional cellular automaton method was used to simulate grain growth during the recrystallization annealing of deep-drawing sheet St 15, taking the simulated result of recrystallization and the experimental result of the annealing texture of deepdrawing sheet St15 as the initial condition and reference. By means of computer simulation, the microstructures and textures of different periods of grain growth were predicted. It is achieved that the grain size, shape and texture become stable after the grain growth at a constant temperature of 700℃ for 10 h, and the advantaged texture components { 111 } 〈 110 〉 and { 111 } 〈 112〉 are dominant.

FLANGE EARING AND ITS CONTROL ON DEEP-DRAWING OF ANISOTROPY CIRCULAR SHEETS

The Hill's quadric anisotropy yield function and the Barlat-Lian anisotropy yield func- tion describing well anisotropy sheet metal with stronger texture are introduced into a quadric-flow cor- ner constitutive theory of elastic-plastic finite deformation suitable for deformation localization analy- sis.And then,the elastic-plastic large deformation finite element formulation based on the virtual power principle and the discrete Kirchhoff shell element model including the yield functions and the constitutive theory are established.The focus of the present research is on the numerical simulation of the flange earing of the deep-drawing of anisotropy circular sheets,based on the investigated results, the.schemes for controlling the flange earing are proposed.

CRYSTALLOGRAPHIC HOMOGENIZATION FINITE ELEMENT METHOD AND ITS APPLICATION ON SIMULATION OF EVOLUTION OF PLASTIC DEFORMATION INDUCED TEXTURE

A crystallographic homogenization method is proposed and implemented to predict the evolution of plastic deformation induced texture and plastic anisotropy （earring） in the stamping of polycrystalline sheet metals. The microscopic inhomogeneity of crystal aggregate has been taken into account with the microstructure made up of a representative aggregate of single crystal grains. Multi-scale analysis is performed by coupling the microscopic crystal plasticity with the macroscopic continuum response through the present homogenization procedure. The macroscopic stress is defined as the volume average of the corresponding microscopic crystal aggregations, which simultaneously satisfies the equation of motion in both micro- and macro-states. The proposed numerical implementation is based on a finite element discretization of the macrocontinuum, which is locally coupled at each Gaussian point with a finite element discretization of the attached micro-structure. The solution strategy for the macro-continuum and the pointwiseattached micro-structure is implemented by the simultaneous employment of dynamic explicit FE formulation. The rate-dependent crystal plasticity model is used for the constitutive description of the constituent single crystal grains. It has been confirmed that Taylor＇s constant strain homogenization assumption yields an undue concentration of the preferred crystal orientation compared with the present homogenization in the prediction of texture evolution, with the latter having relaxed the constraints on the crystal grains. Two kinds of numerical examples are presented to demonstrate the capability of the developed code： 1） The texture evolution of three representative deformation modes, and 2） Plastic anisotropy （earring） prediction in the hemispherical cup deep drawing process of aluminum alloy A5052 with initial texture. By comparison of simulation results with those obtained employing direct crystal plasticity calculation adopting Taylor assumption, conclusions are drawn that the proposed dynamic explicit crystallographic homogenization FEM is able to more accurately predict the plastic deformation induced texture evolution and plastic anisotropy in the deep drawing process.

Comparative Study of Earing Behavior in Cold Rolled-batch Annealed and Cold Rolled-Continuous Annealed of DoubleReduced (DR) Tinplate Steels

Two double cold reduction-drawn and redrawn(DRD) tinplate steels of the same chemistries that have been processed by continuous and batch annealing line have been researched. The composition of fibers were studied through X-ray diffraction. The results indicate that a strong intensity of {114}<110> was formed in the continuous annealing steel and a strong intensity of {111}<112> was formed in the batch annealing steel; not only that but the γ fiber slowly rotated to the low angel α fiber with the angel being about 30° nearly {112}<110>texture owing to the higher second reduction.

INFLUENCE OF STRESS STATE IN EARING PREDICTION (Ⅱ) CRYSTALLOGRAPHIC ANALYSIS OF BCC METALS

The influence of stress state on earing behavior in cup drawing of BCC metals is analyzed by use of the modified Tucker method. The results show that, this influence varies with orientations, and that the earing behavior can be well predicted by the total slip model.

INFLUENCE OF STRESS STATE ON EARING BEHAVIOR──（Ⅰ） CRYSTALLOGRAPHIC ANALYSIS OF FCC METALS

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退火温度对铸轧3003铝合金冷轧板带材冲压制耳率的影响

3003铝合金在铸轧工艺过程中,存在制耳率不理想的问题。基于此,以3003铝合金冷轧1 mm板带材为研究对象,并结合EBSD检测手段,研究了不同退火温度下3003铝合金冷轧板材冲制过程中制耳率与退火温度及织构组织之间的关系,并最终得出影响制耳率的关键因素。结果表明:3003铸轧产品冷轧退火后铝合金板材中的织构主要由Copper、Brass、S、Goss等形变织构和Cube、CubeND、P、R、黄铜R等再结晶织构组成,随着退火温度的升高,形变织构向再结晶织构的转变倾向增大,且显著伴随S型织构及R型织构的减少,Cube型及CubeND型织构的逐渐增加,当形变织构与再结晶织构比值在0.67~0.73时,冲压效果明显改善,制耳率效果理想。

成品退火温度对3003铝合金带材制耳率的影响

针对3003铝合金冷轧带材在冲压过程中因其织构组织容易产生制耳现象,利用扫描电镜EBSD分析技术,研究了成品退火温度对织构及制耳率的影响。结果表明:3003铝合金带材中的织构主要由Copper、Brass、S、Goss等变形织构和Cube、CubeND、P、R、黄铜R再结晶织构组成,且随着退火温度的升高,变形织构逐渐减少,再结晶织构逐渐增加;当变形织构与再结晶织构比值在0.55~0.68范围内,且再结晶立方织构与变形织构S织构、Copper织构、再结晶R织构达到一定的平衡时,制耳率最小。

生产工艺对1100铝带材制耳率的影响

研究生产工艺对热轧1100铝带材制耳率的影响,发现铸锭均匀化热处理工艺、热轧终轧温度、热轧厚度、冷轧中间均匀化退火、冷轧成品道次加工率对热轧料1100-H14铝带材的制耳率有显著影响。铸锭热处理工艺和冷轧中间均匀化退火都能促进相的转变、固溶和析出,改善铸造组织,减少再结晶退火时的立方织构比例。提高热轧终轧温度能促使热轧坯料发生回复再结晶,增加热轧坯料的立方织构比例,热轧坯料完全回复再结晶有利于最终成品的制耳率和性能稳定。提高热轧厚度和冷轧成品道次加工率都能增加冷轧成品的变形织构比例,但冷轧成品道次加工率会影响最终成品的强度和塑性,进而影响后续的深冲性能和制品性能。因此,实际生产过程中需要综合考虑这些影响因素,才能使冷轧成品获得均衡的织构比例和优良的深冲性能。

基于图像处理技术的大田麦穗计数!

为了实现不同播种方式下单位面积小麦穗数的智能计算,设计了一种利用图像分析技术实现大田麦穗快速计数的方法,分析了利用颜色特征和纹理特征分割麦穗的优缺点和粘连区域麦穗个数的计算方法。通过对撒播和条播各35幅样本图像进行计数实验,准确率分别为95.77%和96.89%。结果表明,利用颜色特征和纹理特征均可提取大田环境下麦穗图像,其中利用颜色特征提取速度快。麦穗骨架角点个数能够反映粘连区域麦穗个数,在条播和撒播小麦田中计数准确率均较高。

3104铝合金板材织构和制耳行为研究

采用金相显微镜 ,X -射线衍射技术和深冲试验等手段 ,研究了主要生产工艺因素对 310 4铝合金板材织构和制耳行为的影响。结果表明 ,采用适当高的温度大压下率热轧以及在中间退火前小压下率冷轧都可以增加其立方织构 { 10 0 }〈0 0 1〉组分 ,使成品板材中同时具有较强的立方织构 { 10 0 }〈0 0 1〉和变形织构 { 110 }〈112〉 ,深冲时出现 0°/ 90°和 4 5°方向共存的 8个小制耳 ,降低制耳率 ,减小各向异性。

金属板材深冲制耳的晶体学计算

根据多晶金属板材塑性变形的晶体学理论，由材料织构定量分析（ＯＤＦ）方法，计算了金属板材的冲压制耳高度分布。考虑到单晶滑移变形及屈服条件，计算出了板坯的径向应变周边分布，然后用取向分布函数（ＯＤＦ）给予加权平均计算多晶金属板材的径向应变，进而计算板坯周边的平均应变及制耳高度。对铝合金板材理论预测的结果表明制耳位置（４５°制耳），制耳个数（４个制耳）与制耳率（ｅ＝４．２９）与实测的结果相吻合。

一种预测织构板材制耳倾向的新方法

提出一种根据板材晶体学织构预测深冲制耳行为的新方法，预测了立方金属板中重要织构组分的制耳倾向类型及相对大小．结果优于传统的晶体学方法，可用于抑制深冲制耳的织构平衡设计．

基于小波变换和规范型纹理描述子的人耳识别

在带有角度的人耳图像上提取有效特征一直是人耳识别的难点.本文提出一种基于Haar小波变换和规范型纹理描述子的人耳识别方法,即先对人耳图像进行Haar小波变换,然后利用更加合理的规范型纹理描述子,同时结合分块与多分辨率思想,共同描述经Haar小波变换后人耳子图像的纹理特征,最后用最近邻分类器进行分类识别.实验结果表明,Haar小波变换可以有效增强图像纹理基元的有效信息;利用规范型纹理描述子提取特征不仅速度快,而且具有很强的鲁棒性,尤其与分块、多分辨率方法相结合时,效果更为显著,明显优于经典的PCA和KPCA方法.

均匀化退火工艺对1100铝带材织构及制耳率的影响

用晶体取向分布函数研究和分析了均匀化退火对1100铝带材织构的影响；比较了（560-580）℃×16h、（520-550）℃×9h两种均匀化退火工艺下得到的铝带材的织构组成。结果表明：不同均匀化退火工艺改变了杂质铁在铝基体中的溶解度以及含铁析出颗粒的尺寸，从而影响了铝带材再结晶退火中产生的立方织构与R型织构、B／R型织构比例以及铝带材的各向异性及制耳率；（560-580）℃×16h处理后材料的各织构比较均衡，而各向异性较弱，制耳率较小，为1．8％，制耳均匀。

深冲用工业纯铝板材的各向异性研究

以1100工业纯铝板材为研究对象，通过拉伸性能及制耳率测定，显微组织及取向分布函数ODF分析手段，探讨了深冲用冷轧工业纯铝板材的力学性能及其各向异性行为。研究结果表踢，随着热处理工艺改变，最终成品表现出不同的各向异性效果，通过工艺方案的调整，板料在560～590℃／12h均匀化工艺下材料织构比例达到较为理想的平衡状态，大大降低了材料的各向异性，板材制耳率低于2％，达到了成品要求。

AZ31镁合金板材冲压成形制耳的晶体塑性模拟

针对AZ31镁合金板材深冲过程中的制耳现象,提出一种基于晶体塑性理论的镁合金板材冲压制耳行为的预测方法。首先,从镁合金温成形时的塑性变形机理(即滑移和孪生共同作用)出发,建立耦合滑移和孪生的适合密排六方结构(HCP)金属的晶体塑性本构模型;在此基础上,编制相关程序,通过结合理论、模拟和实验的方法确定镁板微观变形机制组合和多晶体模型参数两个关键因素,构建了适用于镁合金板材大变形的晶体塑性有限元仿真模型;最后,采用HCP板材大变形晶体塑性有限元模型对AZ31镁合金板材的杯形件冲压过程进行有限元仿真,并利用实验结果从制耳轮廓和变形织构两方面验证HCP晶体塑性理论预测冲压制耳的准确性。实验与模拟结果均表明,冲压杯形件呈现出显著的偏离轧向45°制耳轮廓以及(0001)<1010>织构组分和拉伸孪晶组分。

基于颜色和纹理特征的异常玉米种穗分类识别方法

针对玉米选种过程中异常种穗的外观缺陷难以准确识别的问题,以玉米种穗为研究对象,通过计算机视觉技术快速识别杂色、缺粒、虫蛀、籽粒杂乱4种异常种穗。选择单目视觉采集装置,采集任意姿态玉米种穗图像,利用凹点匹配算法分割粘连玉米种穗;采用HSV和CLBP(完全局部二值模式)方法提取玉米种穗的颜色和纹理特征,利用匹配得分融合算法融合玉米种穗的颜色和纹理特征,建立玉米种穗分类模型,利用SVM实现4种异常玉米种穗的快速分类。试验结果表明,该方法相对于传统玉米种穗检测技术能快速有效识别出4种异常玉米种穗,对杂色、缺粒、虫蛀、籽粒杂乱玉米种穗的识别正确率分别达到了96.0%、94.7%、93.6%和95.3%,玉米种穗在有粘连和无粘连情况下平均识别速度分别为每穗1.180 s和0.985 s,能够满足异常种穗分类识别的需求。