槽钢辊弯成形过程的有限元仿真

以大变形弹塑性有限元方法为基础．利用MARC软件对槽钢板坯进行了三维大变形模拟，分析了在辊弯成型过程中不同道次辊压所造成的槽钢各部位应变和应力的分布情况．揭示了槽钢在成型过程中金属的变形规律。从而为生产与设计，特别是孔型设计提供了可靠的理论依据．为计算机孔型设计与制造系统奠定了基础。     

辊弯成型中的纵向弯曲

纵向弯曲是辊弯成型中存在的普遍现象。由于辊弯成型过程的复杂性,孔型的设计和成型道次数目对纵向弯曲的影响仍然靠经验来确定。利用ANSYS/LS-DYNA软件中的显式动态有限元模块,模拟槽钢辊弯成型过程;并将模拟后的结果与实验数据进行对比;通过改变成型角的尺寸、成型道次的数目和成型底线布置,得到了不同情况下的纵向应变和下弯值,从而找出产品辊弯成型时纵向弯曲的规律,为槽钢辊弯成型设计提供了理论依据。     

外卷边槽钢多道次辊弯成型数值模拟

利用有限元软件ABAQUS对外卷边槽钢的多道次辊弯成型过程进行了数值模拟。基于动力显示算法,采用引导板料入辊方式建立了外卷边槽钢多道次辊弯成型有限元模型。分析了成型过程中槽钢的金属变形状态与应力应变场的变化情况,并重点研究了外卷边槽钢边部纵向应变、内外弯角处厚度与横向应变在成型过程中的变化情况,为优化多道次辊弯成型工艺提供了理论依据。     

借鉴国外经验促进我国冷弯钢板桩生产的发展

介绍了采用辊式冷弯成型的冷弯钢板桩产品的特点、应用、分类及其在国外的发展情况,并对加快发展我国的冷弯钢板桩产品提出了建议。     

电器控制器面板注塑模设计

根据电器控制器面板产品的结构特点,介绍了注塑模的成型过程,提出了采用弯销与滑块配合的内侧向抽芯结构以及斜顶杆顶出脱模机构的脱模方式,解决了注塑成型后塑件扣位的脱模问题.经批量生产验证:模具结构保证了成型工艺的顺利完成,且模具的整体结构简单实用.     

厚壁大直径0Cr18Ni9Ti钢管弯头制作工艺的研究

厚壁大直径不锈钢管的扩径推弯成型是无缝弯头成型的难点。针对φ406．4mm×32mm-R610mm的厚壁0Cr18Ni9Ti钢管弯头扩径推湾成型过程，校核了芯棒的强度，提出了芯棒的合理材质及加工方法，确定了芯棒的形状、温度分布及成型管还与感应圈之间的间隙等。经生产验证，其结果合理可行。     

冷弯型钢四辊轧制技术

四辊轧制成型是冷弯型钢生产中的一种新的成型工艺，能显著地改善产品的加工性能和表面质量，并能灵活地配置轧辊组合，降低生产成本。     

跌落仿真技术在注塑成型中的应用

针对产品在跌落过程中出现的破裂现象 ,利用计算机仿真技术对电子注塑产品的成型过程和跌落冲击过程进行了仿真和模拟。分析和研究了制品跌落时的应力分布以及不同注塑浇口位置对注塑件在跌落冲击情况下所造成的可能破裂的问题。研究结果表明 ,改变注塑成型工艺参数 ,可使注塑制品在受冲击时破裂的危险系数降低。由此 ,可提高产品抗跌落、抗冲击的能力 ,并提高电子产品的质量和使用的可靠性。     

矩形断面环形件弯曲成形过程中断面变形的研究

本文采用三维弹塑性有限元方法对矩形断面环形件冷态弯曲成形过程的断面变形问题进行分析研究,通过对成型过程的计算机仿真,分析了在—定宽度和高度工况下弯曲成型后断面形状的变化,对确定矩形断面环形件生产过程中坯料的断面尺寸具有指导作用。     

基于Moldflow的模具镶件偏移CAE优化分析

以筷子盒模具设计为例,针对模具镶件在注塑成型过程中出现被冲弯或冲裂而产生镶件偏移现象,应用Moldflow软件对产品和镶件注塑成型的浇口、流道设计进行优化分析,寻找偏移原因,发现填充不均匀是产生镶件偏移的关键。通过调整浇口进胶方式、流道分布等措施将最大偏移量由1.208 mm降至0.301 mm,显著提升了产品的注塑成型质量。     

管子双向冲模设计

分析了某水管的内凹成形工艺,针对其工艺特点设计了双向冲压成形模,该模具采用上下对冲凸模和带抽芯两瓣式凹模结构,采用双向成形、气动抽芯、滑块导向等方法成形对称内凹部位,成形效率高,产品对称度和尺寸精度好,模具磨损小、寿命长,取得了良好的使用效果。     

3D FE analysis on the product defects of composites formed by liquid–solid extrusion process

The liquid–solid extrusion process for forming composite products was simulated by the three-dimensional thermo-mechanical finite element method. The mechanism for forming defects was analyzed based on the distribution of temperature and flowage of the work piece. The surface annular cracks occurring at the initial stage was caused by the high deformation temperature together with the axial tensile stress which was caused by uneven axial flow rate. However, the low deformation temperature in the terminal stage led to high resistance of deformation and interfacial strength, resulting in the fracture of fibres during severe deformation. The deformation condition in the middle stage was feasible to obtain composite products that were defect free. The simulation was verified through the comparison of the deforming force between the calculated and the measured one in laboratory conditions. The results indicate that the forming quality depends on the thermal and deformation state of the work piece, which can be controlled by the selection and adjustment of the process parameters.     

带有锥台及沟槽钢芯温楔横轧成形分析

采用楔横轧工艺,用温轧轧制钢芯,并对其成形过程进行研究。根据零件的成形特点,采用UG软件设计楔横轧不同工艺参数需要的模具,采用Deform软件模拟成形过程,从中选出最佳的工艺参数,并分析该工艺参数下钢芯大弧体不同成形阶段径向截面等效应力、等效应变及轴向截面等效应力、等效应变,最后通过实验轧制出产品。结果表明:成形角、展宽角等工艺参数对轧件外形及心部质量有很大影响;采用合理的楔横轧工艺参数可以轧制出心部无缺陷的合格产品;轧件的等效应力及等效应变均存在一定的规律,且最大值均在合理的范围内。     

Microstructure and Properties of 7075Al Alloy Fabricated by Directly Combined of Spray Forming and Continuous Extrusion Forming under Different Atomization Gas Pressures

A new process consisting of the spray forming and the continuous extrusion forming for manufacturing 7075Al alloy was proposed.The microstructure evolution,mechanical properties and the resistance to stress corrosion cracking of the alloy were studied.The results indicate that the spray forming process induces obviously grain refinement and greatly lower segregation microstructure.Besides,the Conform process produces finer grains and conduces to more uniform distribution of the precipitates of Al Cu and MgZn_2 phases.The fabricated alloy shows good comprehensive mechanical properties and superb performance of stress corrosion resistance.Moreover,a better combination of the mechanical properties and the resistance to stress corrosion cracking could then be obtained under a certain condition of atomization gas pressure of 0.19 MPa.The enhanced properties are attributed to the following factors,which include the grain refinement,the fine and homogeneous distribution of Al Cu and MgZn_2 phases,the high density of the extruded products,as well as the discontinuous distribution of the grain boundaries after retrogression and reaging(RRA)heat treatment.     

集成电路引线冲切成形技术研究

介绍了集成电路封装形式的演变过程,总结了表面贴装类产品在传统成形工艺下产生的缺陷,并提出了一种新的集成电路冲切成形结构,此结构的优点是减小了条料与成形零件的接触面,产品成形后对多余的引线脚采用整体切断,改善了产品的外观,减小了引线脚的擦伤,控制了产品的成形尺寸及平面度。     

Investigation of the coating thickness of plasma-transferred arc deposition welded and cross wedge rolled hybrid parts

Most of today’s technical parts and components are made of monolithic materials. These mono-material components produced in established production processes reach their limits due to their respective material characteristics. Thus, a significant increase in production quality and efficiency can only be achieved by combining different materials in one part. Bulk forming of previously joined semi-finished products to net shape hybrid components that consist of two different materials is a promising method to produce parts with locally optimized characteristics. This new production process chain offers a number of advantages compared to conventional manufacturing technologies. Examples are the production of specific load-adapted forged parts with a high level of material utilization, an improvement of the joining zone caused by the following forming process and an easy to implement joining process due to the simple geometries of the semi-finished products. This paper describes the production process of hybrid steel parts, produced by combining a plasma-transferred arc deposition welding process with a subsequent cross wedge rolling process. This innovative process chain enables the production of hybrid parts. To evaluate the developed process chain, coating thickness of the billet is analysed before and after cross wedge rolling. It could be shown, that the forming process leads to an improvement of the coating, meaning a more homogeneous distribution along the main axis.     

筒形件正旋旋压力及位移分布规律的有限元分析

筒形件强力旋压时旋压力三个分量及其分布规律是确定设备功率及结构参数的重要依据。本文采用三维弹塑性有限元法对筒形件强力旋压工艺进行了分析 ,得到了正旋时变形区接触面上旋压力 3个分量的分布规律 ,计算结果与叶山实测结果吻合较好 ;同时得到毛坯内表面各节点的位移分布规律 ,为合理选择工艺参数 ,提高产品的尺寸精度提供了理论依据     

大型盘类件成形工艺及模具设计

分析了大型盘类件——驱动盘的结构特点及现有设备的情况,经过分析、计算、试制,采用径向分料方法分2步成形,扩大了自由锻设备的加工范围。详细论述了驱动盘的锻造工艺方案、模具设计过程、模具结构及工作过程。该工艺及模具已在实际生产过程中得到验证,是一种具有投资少、生产周期短、锻件质量好、不需要大型模锻设备的先进工艺。     

Numerical simulation and its application ofrheological forming of titanium alloy vane disk

The hot rheological forming method was proposed to form the second titanium alloy vane disk. The hot rheological forming process of the TC 11 titanium vane disk under a certain temperature and different strain rates was investigated by using the bulk forming software of DEFORM 3D. A series of results including temperature field, equivalent strain distribution, load-stroke curve and rheology procedure were obtained by this finite element method. The rheological forming characteristics were well realized and the forming parameters were determined. The results and analysis show that with decreasing strain rate, the metal flow more equably and the filling of the vane shape is also better. Moreover, the mechanical properties and microstructures of the products produced by this new technique are improved evidently compared with that produced by traditional method.     

Numerical simulation of various cross sectional workpieces using conventional deep drawing and hydroforming technologies

This study focuses on the determination of optimum sheet metal forming process and process parameters for various cross sectional workpieces by comparing the numerical results of high-pressure sheet metal forming, hydro-mechanical deep drawing (DD) and conventional DD simulations. Within the range of each cross section, depth, characteristic dimensions ratio and fillet radius have been altered systematically. Steel of types St14 and DC04 have been used as the specimen material in the numerical analyses and the experimental verification throughout the study. All numerical simulations have been carried out by using a dynamic–explicit commercial finite element code and an elasto-plastic material model. During the analyses each workpiece was simulated by the three competing processes. The results of analyses, such as sheet thickness distribution, necking, forming of radii etc., are used for assessing the success of each forming process alternative. The analyses revealed that depending on the workpiece geometry and dimensional properties certain processes are preferable for obtaining more satisfactory products. Working windows for each process have been established based on the analyzed parameters of the circular, elliptic, rectangular and square cross sectional product geometries. This data is expected to be useful for selecting the appropriate production process for a given workpiece geometry and understand the limits of each sheet metal forming processes.