利用正交试验设计优化冷弯成形工艺参数

冷弯成形工艺参数的设计对冷弯成形产品质量有重要影响。本文对方矩形管冷弯成形过程中机架间距、摩擦因数和轧制速度的不同取值水平通过正交试验设计,利用Abaqus有限元软件的显式非线性动态分析对所设计试验仿真模拟,得到了每道次轧制过程中带钢边部最大纵向应变最小时各个道次3个工艺参数的最佳取值。并用优化后的参数进行仿真和验证,得到各道次带钢边部最大纵向应变比优化前要小,优化后第4~第10道次带钢纵向应变极值相对接近,产品边部拉伸小,并且边部拉伸分布比较均匀,有效改善了产品质量。     

In situ observation of the interface between a roll and a sheet in flat rolling process

In metal forming processes, the interface between a workpiece and a tool was occasionally observed directly. However, the rolling interface has almost never been observed because of high-speed roll rotation. To achieve the in situ observation, this paper proposes a novel method where one roll is fixed in the space without rotation, while the other roll revolves around the fixed roll with rotation. With passing the gap between the two rolls, a sheet is rolled. A prototype machine with transparent rolls was fabricated, then the interface in solder rolling was successfully observed from the interior of the fixed roll.     

Analytical and experimental study on the spiral marks of the rolled product during three-roll planetary rolling processes

In this study, the effects of various rolling conditions, such as inclined angle, offset angle, roll shapes, etc., upon the depth of the spiral marks on the surface of the rolled product and the rolling forces are discussed numerically by the finite element method. Experiments using a self-designed testing machine with work-rolls of three different kinds of roll shapes were conducted. The depth of the spiral marks was measured. From the comparisons between the analytical and experimental results, it is known that a smoother surface on the rolled product can always be obtained with convex-shaped rolls. Whereas, prominent spiral marks probably appear for two-stage conical rolls and spherical-headed rolls under an ill-set rolling condition. These analytical and experimental results can offer useful knowledge for the design of the roll shapes and the pass schedule during three-roll planetary rolling processes.     

钛合金大型环件热辗扩成形应力-应变场演变规律的尺寸效应(英文)

基于可靠的钛合金大型环件热辗扩成形过程热力耦合三维有限元模型,研究并对比了不同尺寸环件的应力应变场演变规律。结果表明:对于不同尺寸环件的成形过程,当γ(整个成形过程的当量每转进给量分配比)减小时,成形结束时的Mises应力峰值可能从环件的驱动辊侧咬入点转移至芯辊侧咬入点,而等效塑性应变峰值有从环件外表面向内表面转移的可能性;当L(整个成形过程的当量变形区长度)增大时,成形结束时的Mises应力峰值可能出现在中间层。成形结束时Mises应力峰值和等效塑性应变峰值的位置是以上两方面综合作用的结果。在成形环件的变形区,环件表层金属处于三向压缩应力状态,中间层金属处于一向压缩、两向拉伸或者两向压缩、一向拉伸应力状态;整个环件处于一向压缩、两向拉伸应变状态。     

Improved Process Design and Quality for Gear Manufacturing with Flat and Round Rolling

This paper describes a new method and its results in the roll-forming of gears that has significantly surpassed the conventional limits known till now. The method describes the rolling process and an alternative pitch design of forming tools. A model was created to analyze rolling processes which determined that in contrast to flat rolling tools, round tools need additional kinematic compensation during diameter-related variable pitch forming processes. This presented method shows up to a 50% improvement in pitch accuracy and the ability to roll high teeth gears (up to 10 mm in height and a tooth-height-coefficient larger than 2).     

热轧花纹H型钢轧制工艺的开发

热轧花纹H型钢是一种绿色环保钢材,可以大大降低钢结构加工成本,马钢在其大H型钢生产线上对热轧花纹H型钢进行了开发。介绍了马钢大H型钢生产线的工艺装备及流程,以Q355B牌号244 mm×252 mm×11 mm×11 mm规格花纹H型钢的开发为例,介绍了钢坯加热制度,开坯、万能轧制工艺和孔型设计,以及矫直工艺。该产品的开发在现有大H型钢产线装备条件下,经过孔型和压下规程的合理设计,采用X-H轧制方法,在万能轧机组最后一道次轧制翼缘外侧花纹,花纹符合标准要求、清晰度优良。与国外轧制工艺进行了对比,降低了对设备精确度的要求,轧制方法更加简便,尺寸调整手段更加多样化,为国内热轧型钢产品开发提供了技术支撑。     

智能与控制在塑性加工制备与成形中的应用

对材料制备与塑性加工方面的智能控制特点进行了介绍与分析。首先对钢铁、铜及铜合金管材连铸连轧过程控制加工特点进行了阐述 ,其次介绍了镁合金的“轧制 等通道角挤压 拉制”连续加工制备技术和镁合金薄板半固态双辊铸轧工艺。对于薄板增量加工成形技术 ,介绍了飞机整体壁板增量压弯技术、薄板单点无模增量成形技术和多点无模增量成形技术。讨论了薄板可动凹模液压成形技术、异型截面管件液压成形技术和细长杆件空间弯扭成形技术原理。最后对于微小件加工技术进行了简要介绍     

Numerical and experimental investigation into cold incremental rolling of doubly curved plates for process design of a new LARS (line array roll set) rolling process

The line array roll set (LARS) rolling process is a new incremental sheet metal rolling process for effective manufacture of doubly curved metal plates. In this study, design equations were developed to predict the curvatures of formed plate shapes with complex curvatures using the experimental data. A series of experiments with various curvatures have been performed. The comparison of the finite element computation results with the design equations has shown that the design equations can be effectively used for process design of forming processes in forming of doubly curved plates over a wide range of input curvatures.     

花键冷滚压精密成形力学分析与数值模拟

分析了花键冷滚压成形过程,对冷滚压精密成形过程的单位平均压力、冷滚压接触面积和滚压力进行了分析与计算.在此基础上,建立了花键冷滚压过程的力学模型与数学模型,并对花键冷滚压成形过程进行了数值模拟.通过对理论分析、数值模拟和试验研究的对比分析,为花键冷滚压成形工艺的研究与应用提供了理论依据.     

高纯铝箔在异步轧制和再结晶过程中取向的演变

采用不同速比的异步轧制技术对99.99%的高纯铝板进行不同形变量的冷轧,并对冷轧样品进行不同温度和时间的再结晶退火.利用X射线衍射技术和TEM观测探讨了异步轧制条件下高纯铝箔中变形织构和再结晶织构的演变.结果表明:高速比的异步轧制(i=1.28)在样品中产生相对较强的旋转立方织构{001}(110).异步轧制后退火的高纯铝箔样品中,立方{001}(100)织构组分的再结晶晶核的形成和长大存在一个临界转变温度,此温度与异步轧制的速比成反比.异步轧制有利于降低高纯铝箔的再结晶温度,这与异步轧制提高高纯铝箔的形变储能有关.异步轧制有利于在低温时形成强的立方{001}(100)织构组分,但此时漫散较大;随着退火温度的升高,漫散范围明显缩至8°-10°.     

Development of satellite mill and trial rolling of profiled metal strip

A new type of compact continuous mill called the “Satellite mill” has been developed to produce profiled metal strip from flat strip. This mill consists of one large-diameter driven roll (central roll) and five smaller rolls (satellite rolls) arranged along the periphery of the central roll. A strip is continuously rolled at five gaps between the central roll and the satellite rolls. All rolls are driven at an equal roll peripheral speed to promote transverse metal flow or lateral spread. Guide shoes are provided between the adjacent satellite rolls and are supported with two adjacent satellite rolls. They prevent a strip from bulging or buckling. A test mill was constructed, and rolling experiments have been performed on the production of T-shaped or U-shaped profiled aluminum strip. The deformation- load characteristics were investigated and compared with those of conventional rolling. As a result, in the satellite mill rolling operation, elongation was suppressed. Lateral spread was enhanced, and the profile of the product cross section was significantly improved. Consequently, the new rolling process was found to be forming of profiled metal strip.     

Large area rolling of functional metallic micro structures

The reliable fabrication of functional surface structures has become an important factor in modern production processes. With regard to the field of large area micro patterning, particular applications demand for economical manufacturing processes to gain advantageous surfaces. The process-integrated rolling of these structures is a promising approach if suitable roll geometries can be manufactured. This paper focuses on the large area rolling of so called riblet structures. Both experimental test series and related numerical forming simulations are taken into account. Furthermore, demands and potentials from the roll manufacturing point of view are highlighted. Above all, the feasibility of a new winding concept for the continuous patterning of rolls with small negative riblet structures is pointed out. By this means, challenging requirements in connection with riblet rolls—the realization of finest structures with sharp ground radii—can be matched.     

从斜轧技术发展看自动轧管机组的改造方向

对斜轧技术的发展和传统斜轧“横锻效应”的副作用作的介绍和分析，并列举几种新型的斜轧穿孔和轧管设备的特点，提出用三步成型轧管工艺代替老式多工序轧管工艺以改造现有自动轧管机组。     

铝带轧机辊型设计及在轧制中的调整

辊型是铝带轧制的重要工艺条件,影响着产品质量及轧制过程能否顺利进行。根据本厂的具体条件,计算了轧制力和它使轧辊产生的挠度,并计算了轧辊受热产生的热膨胀,确定了轧辊辊型。论述了根据生产实践调整辊型的措施。     

有限元法处理金属塑性成型过程的接触问题

用有限元法模拟金属塑性成型过程的难点之一是接触边界条件的处理 ,本文着重介绍了处理金属塑性成型过程中接触问题的一般方法 ,包括接触边界的搜索、接触力的计算及接触热传导的计算三方面内容。运用 ANSYS提供的接触单元 ,模拟了 Y型三辊轧制过程及钢轨矫直过程的接触状态 ,结果与实际相符     

Use of Taguchi method to study a robust design for the sectioned beams curvature during rolling

Finite element DEFORM™ 3D software is employed to examine the plastic deformation behavior of V-sectioned and T-sectioned porous beams at the roll gap under various rolling conditions. The finite element code is based on a rigid–plastic model in which it is assumed that the rolls are rigid bodies and that the temperature change induced in the beams during rolling is sufficiently small that it can be ignored. The analytical model is used to systematically examine the effect of the inclination angle of the roll profile, the friction factors between the rolls and the beam, the roll radii and the angular speed of the upper and lower rolls on the curvature of the rolled beam, the rolling torque, the effective strain, the effective stress and the variation of density of the rolled product at the exit. The Taguchi method is employed to design the rolling parameters to optimize the curvature of the beams. The analytic results have shown that: (1) the inclination angle of the inner part (i.e. vacancy) of the upper roll, the friction factor of the lower roll, the angular velocity of the lower roll and the roll radii, respectively, all have a significant influence upon the curvature of the rolled V-sectioned product, κ = 1/r_a; (2) the reduction ratio of the porous beam, the friction factor of the lower roll, the angular velocity of the lower roll, and the roll radii, respectively, all have a significant influence upon the curvature of the rolled T-sectioned product, κ = 1/r_a.     

凸轮轴轧制工艺的研究

主要介绍了利用楔横轧机轧制凸轮轴毛坯,轴类零件轧制工艺的过程和轧制技术的基本原理及应用过程、应用条件、产品鉴定和发展前景.     

动力显式有限元法辊弯成形全流程仿真技术研究

辊弯成形是大位移、大转动、有限应变的过程,具有复杂的非线性特征,成形规律难以通过传统“试错法”把握。为避免成形缺陷,降低开发成本,采用有限元法对辊弯成形进行全流程仿真,可以准确预测辊弯成形过程中应力-应变分布与变化规律,辅助工艺设计与产品开发。采用动力显式算法,可以缩减计算规模,避免隐式算法的迭代收敛问题等限制,容易实现大规模并行计算,减少计算时间。通过对槽型件的辊弯成形进行全流程仿真实例,验证了该方法的有效性。     

基于弹塑性有限元的板形控制机理研究现状与展望

带钢冷连轧过程中的板形控制问题因具有多变量、多控制回路、非线性和强耦合等特征，是工业控制领域最为复杂的控制过程之一。精准的板形预测模型是提高板形控制水平的重要保证。当前，弹塑性有限元法能够耦合分析轧制过程中带钢的弹塑性变形、轧后的残余应力以及轧辊的弹性挠曲、弹性压扁，因此在带钢轧制领域有很广泛的应用。介绍了现代板形控制系统的工作原理，以及当前弹塑性有限元法关于板形控制问题分析的研究进展。同时，采用显式动态有限元建立了六辊UCM轧机的三维数值仿真模型，研究了不同板形调节机构对带钢板形的调控特性及其最优调节量，并采用实际轧制试验对模型进行了验证。结合带钢保持良好板形的几何条件，利用所建立的UCM轧机模型，分析了中间辊轴向横移、工作辊与中间辊弯辊对带钢横截面形状、凸度、边降及平直度的影响。最后，对有限元法应用于分析板形控制问题的方向进行了展望。     

20辊轧机轧制宽幅工业纯钛带的变形行为研究

基于ABAQUS有限元软件,考虑了钛金属的各向异性力学特点,建立了可实现工作辊与轧件动态轧制过程的20辊轧机辊系-轧件一体化模型,并利用实际轧制数据对模型计算精度进行了验证。同时,利用该模型对20辊轧机轧制宽幅工业纯钛带的单一以及组合板形调控特性进行了仿真研究。结果表明:支承辊1#与7#、2#与6#对称位置分段压下与一中间锥辊窜辊组合调节时,随着窜辊量的增加,距边部75～300 mm区域厚度减薄最为显著,将导致或加剧该区域的二肋浪形;3#与5#、4#对称位置分段压下与一中间锥辊窜辊组合调节后,对缓解二肋浪形具有一定作用;此外,还发现一中间锥辊窜辊调节无法解决二肋浪形问题。最后,结合20辊轧机板形调控特性,提出了一种能够减小二肋浪形区的压应力的分段压下组合方案,工业实验证明分段压下组合方案实施后二肋浪形区压应力下降60%,有效缓解了20辊轧机轧制宽幅钛带时的二肋浪形缺陷及程度。