板状带凸台件的精冲-挤压复合成形分析及工艺设计

总结了半冲孔型、挤压型和模锻型3种典型板状带凸台件的成形类型和特征,并以其中最具代表性的挤压型凸台作为研究对象,分析了板件挤压与正挤压在成形方面的区别,通过分析挤压型凸台成形过程中出现顶部凸起、底部缩孔、根部裂纹和外围凸包4种常见缺陷的原因,进一步提出了相应的解决措施。根据板件挤压凸台成形力的影响因素建立了计算板件挤压凸台成形力的经验公式。给出了在模具尺寸设计时,不同凸台相对高度下的挤压凸台底部孔直径的参考值;指出了凹孔直径即凸模直径越大,则成形力越大,对模具寿命不利。     

中厚板的反挤凸柱成形规律

运用有限元软件DEFORM-3D对5 mm厚的20钢中厚板进行了反挤凸柱成形模拟研究,对比分析了封闭式模腔、全开式模腔、半开式模腔挤压成形时材料的变形特点。研究揭示了3种成形方式下金属的流动规律、等效应力及等效应变的分布、载荷与行程的关系,从而可根据成形载荷、凸柱高度与凸凹模行程的关系来合理选择模腔形式。进而研究了凸凹模圆角半径、凸柱直径与坯料初始直径之比d/D、凸凹模下行速度等因素对于各挤压方式下凸柱高度的影响。最后,选取半开式模腔成形凸柱进行实验,实验结果和有限元模拟结果符合较好,验证了有限元模拟的准确性。     

凸起成形的底部压缩拉深法研究

介绍了凸起成形的一种新加工方法-底部压缩拉深法.采用DEFORM-2D有限元软件对薄板上凸起成形的底部压缩托深法和反挤压加工法进行了模拟分析.模拟结果表明:成形同一高度的凸起时,底部压缩拉深法所需的加工载荷小,加工载荷稳定,所需工件的初始板厚也较小.通过研究,表明了底部压缩拉深法的优越性.     

A Combined Radial Forging-Forward Extrusion Forming Process of Alternator Poles

A combined radial forging-forward extrusion forming process of alternator poles is proposed based on an analysis of the structure of alternator poles as well as the forming die sets. First, a thick-bottom base of the alternator poles is obtained through radial forging. The middle boss and claw teeth are then formed through forward extrusion. A 3D coupled thermomechanical finite element model is employed. Billet deformation, metal flow, and forming load are obtained. The results show that the middle boss cavity is filled earlier and the process is no longer simultaneous extrusion during the second forming step. Then, the forming load increases sharply. An improved process that controls the metal flow in the middle boss cavity and aids in pushing the metal into the corners of the claw teeth cavity is proposed. The middle boss and claw teeth cavities can be filled simultaneously. The sharp increase of the forming load in the final forming stage is avoided. Simulative and experimental results show that the improved process can considerably reduce the final forming load to form a well-shaped product.     

锥形凸台体积成形的一种合成力学模型

锥形凸台成形是金属体积成形工艺中一种典型的局部成形。该文通过分析锥形凸台在不同体积成形工艺中的成形机理,基于模块化思想,将其成形过程划分为挤压成形与角部充满两个特征时段,并将两个特征时段的滑移线场力学模型有机联结,构建了锥形凸台成形过程的一种滑移线力学模型,并介绍了应力场与变形力的求解方法。该模型丰富了金属体积成形过程的特征单元库,可套用于局部成形的应力场与变形力求解,实现局部成形的模具优化设计。     

基于均衡思想高凸台圆柱直齿轮冷锻成形

利用浮动凹模和梯形槽分流法成形大模数高凸台圆柱直齿轮,存在上下凸台成形不同步,载荷偏大的问题.基于均衡思想,提出了改进的模具结构.通过在下模上增设一直径15 mm的半球台,对流入下凸台的金属进行约束.利用三维有限元仿真软件数值模拟齿轮成形过程,通过对材料变形的应变场、应力场、行程载荷曲线等规律的分析,确定改进后的模具结构,有利于均衡成形并降低成形压力.物理实验验证了仿真分析的结果.     

铝合金挤压非正交网格有限体积法数值模拟

利用非正交网格,将铝合金挤压金属流动区域离散成不规则六面体有限体积控制单元,充分考虑网格非正交性对铝合金挤压金属流动控制方程离散过程的影响,研究了非正交网格下铝合金挤压有限体积法模拟关键技术。建立了基于非正交网格的铝合金挤压过程有限体积法数值模拟模型,并编制了相应的分析程序。对典型铝合金挤压过程进行了模拟,并与有限元分析软件Deform-3D模拟结果进行了分析比较。分析结果验证了本文铝合金挤压有限体积模拟模型的正确性。     

Research on nail-sheet joining by multi-plate extrusion via the three-quadrant method

In this paper, in-plane nail-sheet joints were created by multi-plate extrusion, a plastic joining method that is an alternative to traditional mechanical joining methods. Nail forming, nail cutting, nail-sheet joining and optional assembling are combined in a single press stroke in multi-plate extrusion, which can be divided into three processing periods that includes two separations. Practical experiments were performed in which compressive forces were dynamically measured at different extrusion depths. An axisymmetric model was created to simulate the process, and its results were compared with the experimental results, where both separation actions were presented. The three-quadrant method was used to estimate the exceeded length of the nail, in which an irrelevant term was required to be added to make up a four-term system which is able to create correspondence to a coordinate system with four quadrants.     

State-of-the-art of plate forging in Japan

The state-of-the-art of plate forging processes for forming complicated parts without cutting and finishing in Japan was reviewed. For cups having comparative large thickness and plates having complicated cross-sectional shapes, plate forging is more useful than conventional billet forging due to due to comparatively small change in shape. In plate forging, forging processes such as upsetting, extrusion and ironing are included in the sequence of conventional stamping composed of shearing, bending and deep drawing in order to control metal flow in plates. Plate forging has the advantages of higher performance, larger productivity, lower cost, etc. Plate forging processes are classified into desired functions of products, local thickening, local thinning, formability improvement and forming of gears and plates.     

套筒类7A04铝合金挤压成形金属流动规律研究

根据等温压缩实验得出7A04铝合金应力一应变数据，拟合出材料温成形应力一应变曲线。应用有限元法模拟7A04铝合金管材的挤压成形，着重探讨7A04铝合金挤压成形过程中，温度、速度等因素对金属流动的影响．为套筒类零件挤压成形工艺提供科学的依据。     

带超高实体凸台的薄板冲压件加工工艺研究

在金属板料成形过程中,由于夹在凸模与凹模之间的板料随着加工的进行变得越来越薄,导致板料向凹模腔内的流动阻力越来越大,从而阻碍材料流向凹模型腔,因此利用传统成形工艺无法在薄板上加工带超高凸台的冲压零件.本文研究了一带超高实体凸台的零件,并根据数值模拟及一系列工艺实验结果,研制了一套连续模,获得了超高凸台冲压零件.研究表明,利用弯曲、镦挤复合新工艺方法能够实现在薄板上加工带超高凸台冲压零件,而且与该零件的其它加工方法相比新工艺具有诸多优越性.     

硅线石颗粒与铝液混融后挤压下流动凝固的塑性变形特征

本文以液态模锻和液态挤压研究为基础，提出了一种新型的颗粒增强金属基复合材料的制造方法，并采用实验观察和理论分析手段，对搅融混合后的半固态浆料的挤压过程进行研究，揭示了复合体在流动中凝固、凝固中塑性变形的力学特征，为正确选择工艺参数和过程的稳定奠定基础。     

Axisymmetric extrusion forging: Effects of material property and product geometry

Experiments have been carried out on lead and copper cylindrical billets using simple extrusion forging dies under quasi-static and dynamic conditions to produce boss and flange type components. It was observed that during the initial stages of the deformation process, the flow pattern of the metal is significantly different to what is normally assumed in theoretically analysing the process. The profile of the flange becomes very much tapered and the height of the boss obtainable is dependent on the boss to billet dimensional ratio.A theoretical analysis is presented based on rigid-plastic property of the billet material which enabled prediction of the tapered deformation profile of the flange under frictionless conditions. The agreement between the theoretically predicted deformation modes and those observed experimentally is found to be very close.     

铝合金搅拌摩擦焊焊核紊流区及性能分析

采用搅拌摩擦焊方法对2219-T6铝合金进行焊接,对焊接接头的宏观形貌、微观组织、抗拉强度进行了分析,并通过对焊核塑性金属的流动状态进行分析,研究了搅拌摩擦焊接头强度弱化的原因. 结果表明,焊核根据流态可分为3个不同的区域,其中靠前进侧存在一个性能薄弱的B区域,该区的产生是抽吸挤压作用不平衡的结果,也是塑性金属向上回流通道. 该区具有较大的塑性损伤,易产生疏松缺陷及界面突变,晶粒具有较大的热不稳定性,是造成接头强度低于母材的主要原因之一. 通过高温短时的再结晶热处理工艺可以恢复该区域的强韧性,消除弱化问题.     

半轴套管热挤压成形数值模拟与实验

根据半轴套管零件的特点,确定了热挤压成形工艺方案,采用DEFORM-3D有限元软件对成形过程进行数值模拟,分析坯料在制坯、正挤压和镦粗法兰3个工序中的应变分布、温度场分布和金属流动规律,得到了凸模载荷-行程曲线图;预测成形过程中缺陷产生的可能性,并分析坯料加热温度、凸模挤压速度、模具预热温度3个主要因素对正挤压成形效果的影响。生产验证了该热挤压工艺的可行性,为半轴套管的实际生产工艺的制定提供了参考依据。     

汽车发电机爪极闭式一火两锻成形工艺研究

在对汽车发电机爪极零件结构分析的基础上,提出了基于结构拆分的爪极闭式一火两锻成形工艺和对应的模具,该工艺先径向墩挤成形出爪极基座部分,然后再反挤出爪齿和中间凸台.利用Deform- 3D建立了工艺过程的热力耦合有限元分析模型,并得到了成形过程中坯料形状变化、材料流动和成形载荷等情况.结果表明:该工艺能够获得齿形充填完好...     

基于数值模拟的挤压参数对AZ91镁合金管转角焊合室分流挤压焊合压力的影响规律研究

提出了一种镁合金管材转角焊合室分流挤压新工艺,该工艺可在有效延长焊合室长度和焊合时间前提下保证舌针刚度,从而保证管材尺寸精度,并且可通过转角剪切变形机制增加预焊合金属变形量和动态再结晶程度,从而有利于提高管材性能和焊缝焊合性能。利用有限元法揭示了转角焊合室分流挤压成形过程中金属的流动特征,应变分布特征和焊合室内的静水压力分布特征。结果表明,整个挤压过程无金属折叠,从而保证管材的表面质量;流经转角后预焊合金属变形量明显增加,有利于提高管材质量和焊缝质量。最后,研究揭示了坯料初始温度,挤压速度和模具转角对焊合室内静水压力的影响规律。结果表明,随着挤压速度的增加和模具转角的增大,转角焊合室内静水压力增大;随着坯料预热温度的增加,转角焊合室内静水压力呈先增大后减小的趋势。     

基于数值模拟的厚板精冲挤压过程分析

针对厚板精密冲裁过程存在的缺陷(塌角与毛刺等),基于Deformed2D分析了10mm厚钢板精密冲裁过程中双齿V形压料板对冲裁质量的影响.采用V形压料板可在一定程度上减小塌角的高度,但不能完全消除.随后采用精冲挤压方法对这一厚板的成形过程进行了分析,结果表明:采用精冲挤压成形工艺后,厚板零件表面塌角得到了完全消除,零件...     

58SiMn钢双杯形件等温挤压成形金属流动规律研究

根据等温压缩实验所得的58SiMn钢应力一应变数据,应用刚塑性有限元法模拟58SiMn钢双杯形件等温挤压成形.着重探讨58SiMn钢等温挤压成形过程中变形力及金属流动规律,从而为该类零件等温挤压成形工艺提供科学的依据.     

Numerical investigation on tooth filling of clutch drum forming processes

The formation of the gear drum clutch involves bulk and sheet forming, and filling the tooth is a key difficulty during the forming process. In this study, four tooth extrusion processes with various extrusion ratios and preform shape were developed, and they were simulated using AFDEX software for examining how the clutch drum influenced tooth forming. Various tooth-filling results were obtained by controlling the extrusion ratio and die cavity in each process. A comparison of the deformation, material flow, and mean stress state among the processes revealed that the stress state was the main determinant of the local flowing material, and it was used to improve the degree of tooth filling. The optimal tooth-filling result was obtained using a two-step extrusion process with an appropriate extrusion ratio and a preform shape.