Upsetting of cylindrical billets between flat platens having unequal frictional properties

A study of upsetting of cylindrical billets between free falling tup and stationary anvil with unequal end friction is made. The effect of unequal interface friction between tup-billet and billet-anvil contact surfaces on the strain distribution and hence the billet profiles as it is deformed to its final shape, together with the variations in tup and anvil loads and energy consumption is predicted theoretically using a numerical technique [1].Upsetting conditions are simulated considering various combinations of tup-billet and billet-anvil interface frictions, ranging from μ = 0−0.5. The billet material is assumed to be elastic linearly strain hardening. Theoretically predicted results are discussed in the light of some experimental evidence.     

Analysis of three-dimensional upset forging of arbitrarily-shaped prismatic blocks

The present study is concerned with upset forging of arbitrarily-shaped prismatic blocks which is characterized by three-dimensional deformation with sidewise spread and bulging along thickness. A kinematically admissible velocity field to incorporate the three-dimensional deformation is proposed. From the proposed velocity field the upper-bound load and the deformed configuration are determined by minimizing the total power consumption with respect to some chosen parameters. Experiments are carried out with annealed AISI 1015 steel billets and commercially pure copper billets at room temperature for different frictional conditions and geometrical shapes such as clover and rounded rectangles. The theoretical predictions both in the forging load and the deformed configuration are shown to be in good agreement with the experimental results. Therefore, the proposed method of analysis in this work can be used for the prediction of forging load and deformation in upset forging of arbitrarily-shaped prismatic blocks.     

圆柱筋条式抽油杆镦锻模具设计

为了满足采油作业的需要,设计了圆柱筋条式抽油杆.与标准规格的方形抽油杆相比,具有抗疲劳强度好且拆卸方便的优点.根据该抽油杆模锻时金属塑性变形的特点,论述了该抽油杆的两个镦锻难点,并做了分析优化,最终确定了φ25.4mm圆柱筋条式抽油杆的镦锻工艺方案.经生产实践证明,使用该工艺方案锻造出的抽油杆强度高、精度好、使用寿命长,具有显著的社会效益和经济效益.     

大型全纤维曲轴的镦锻成形工艺研究

本文通过DEFORM-3D对全纤维曲轴三步法的镦锻工艺进行了有限元模拟,并且分析了金属流动规律和变形分布情况。从而优化了其工艺过程和工艺参数,这些结果可以为生产试验提供理论依据。     

管坯镦锻工艺仿真及优化

管坯镦锻制品是石油、钻探等机械设备的关键部件,要求具有很高的强度、抗拉性能及抗疲劳性能。在实际生产中,管坯成形过程很容易产生失稳、内部凹陷甚至折叠。而且坯料体积不易控制。使得锻件成形困难,锻件质量得不到保证。本文采用Deform-3D塑性有限元分析软件,以钻杆头部镦锻为例对管料的镦锻成形工艺过程进行了模拟和分析．并针对原有成形工艺中出现的问题进行了改进和优化。运用Deform-3D系统模拟的油管与生产实际基本吻合,因此,该模拟结果及其参数可用于钻杆头部镦锻模的设计。     

气门锻模渗硼工艺研究

针对3Cr2W8V钢制造的锻模,常规热处理后因变形或模腔起皱而失效,效率低、成本高等缺点,提出对气门成型锻模进行渗硼强化工艺研究,找到了适合于锻模渗硼的热处理工艺。锻模使用结果表明,使用寿命是原淬火+回火的2倍,社会效益与经济效益明显提高。     

压力机生产锻件错差原因及解决办法

着重分析了热模锻压力机生产的锻件因设备磨损、工装磨损、锻模加工精度、安装规范和错移力五类比较常见的原因造成错差及其形成机理,并通过多年现场经验针对这五类原因依次采取用塞规检查压力机导轨间隙、导向杆与导向套配合间隙、用三坐标测量仪检查模具精度、制定模具安装规范和模具优化设计等措施检查和解决,这对生产实践及提高锻件质量都具有非常重要的意义。     

考虑热影响的6300kN多向液态模锻液压机机身结构变形分析

液态模锻模具在生产过程中具有一定的温度,使机架同时受到热和力的作用。在研究液态模锻液压机机架结构特点的基础上,以Ansys Workbench软件为平台,综合考虑温度和受力情况对机架的影响,对液压机机架进行了有限元分析。结果表明:采用结构静力分析与热应力耦合分析时,机架的最大变形都出现在上横梁液压缸法兰作用的环形面上,分别为0.9938和1.2735 mm;考虑热影响时液压机工作台的应力应变值明显增加,并且立柱的最大变形部位发生变化,由结构静力分析时的中上部变为中下部,径向变形明显增大,由0.1827 mm上升为0.6148 mm。     

大型全纤维曲轴平衡块成形塌角问题研究

针对曲轴锻造平衡块塌角问题,从加热、工艺、模具等不同的角度分析了锻造过程中可能出现缺陷的原因,阐述了NTR法的锻造工艺特点和相应的解决措施,并简单介绍了德国的“CATEAR”镦锻模具。通过实际生产验证了NTR法锻造的可行性和优越性,为全纤维曲轴的锻造提供了新的理论依据和实际经验。     

齿轮温锻模具磨损失效分析北大核心CSCD

为了延长齿轮温锻凹模的使用寿命,借助DEFORM软件和Archard模型对齿轮闭式温锻成形过程进行模拟分析,预测凹模磨损最严重区域,并利用响应曲面法建立齿轮温锻凹模磨损量编码因子方程,以凹模预热温度、凹模硬度、冲孔连皮厚度和凹模齿顶过渡圆角半径作为目标参数对凹模磨损最严重区域进行参数化分析。预测结果表明:齿轮齿形填充饱满,轮齿不存在塌角现象,优化后磨损最严重区域的磨损量为1.42×10^(-5) mm,与回归模型预测值比率相差5.63%,误差较小;对应的最优参数组合为:凹模预热温度为150℃、凹模硬度为55 HRC、冲孔连皮厚度为2.7 mm和凹模齿顶过渡圆角半径为0.4 mm,预测齿轮温锻凹模寿命为7746件,符合生产预期的6500件。说明响应曲面法预测结果较为准确,可一定程度上降低试模成本。     

400MN多向模锻液压机承载结构的普通模锻工作性能分析

采用预应力钢丝缠绕正交预紧机架作为承载结构的多向模锻液压机进行单一垂直方向的普通模锻工艺时,垂直油缸提供的加载力被直接施加于毛坯件表面.由于所加工毛坯件的温度偏差、材质不均、形状不对称性等多种因素的影响,多向模锻液压机承载结构必然会出现偏心载荷状态,工况危险.因此,利用有限元分析方法和1:10模型试验,对400 MN多向模锻液压机承载结构在3种偏心载荷状态(前偏载、右偏载、斜向偏载)下的工作性能进行研究,得出在偏载状态下预应力钢丝缠绕正交预紧机架的变形特性与承载能力可以满足400 MN多向模锻液液压机的承载需求.     

双分型面挤压铸造模设计与应用

借鉴双分型面塑料模结构设计方法,结合挤压铸造模自身特点,优化设计了适合中心浇口进料的双分型面挤压铸造模,此类模具可以实现凝料与直浇道的自动分离,方便取出浇注系统凝料和铸件,得到的铸件组织致密且具有较高尺寸精度。设计的摆钩分型螺钉定距机构可以提供较大拉力拉断浇口,实现模具2个分型面的依次打开。在此基础上探讨了带侧抽芯机构的双分型面挤压铸造模的结构特点和设计要点。     

活塞尾锻造工艺分析及数值模拟

详细分析了活塞尾锻件模锻工艺方案及关键技术特点，提出了闭塞制坯、终锻成形及切边工艺方案，并用Deform-3D软件进行有限元模拟分析。模拟结果显示，只要在两工步间合理分配变形量，即可顺利成形锻件；同时，斜底凸模较平底凸模更容易制坯。该工艺方案可行，能保证生产时工艺的稳定性。     

A wire cutting test to check the temperature distribution in inductively heated cylindrical aluminium billets at semi-solid material state

A fast test has been developed to evaluate the homogeneity of the temperature field within aluminium cylindrical billets heated up to their semi-solid state. This method is based on the evaluation of force measurements during cutting of the heated specimens by a thin wire, considering that the shear stress of thixo-tropic Al-alloys is significantly deteriorated at thixo temperatures. The obtained results were explained by FEM supported calculations of the occurring thermal field within the billet. Moreover, the measured cutting forces versus the wire displacement were verified by a FEM based simulation of the introduced test. The developed method enables a fast assessment of the specimen heating uniformity and contributes to an undisturbed conduct of semi-solid high-pressure die casting.     

闸瓦销辊锻咬入条件分析

就闸瓦销的外形特征,分析了自由咬入时,模具及辊轮参数的合理性。     

A study of a die set for the multiway die forging of pipe joints

This paper presents a new type of die set for the multiway die forging of pipe joints. The kinematic equation of the wedge working mechanism of the die set and the optimum ratio of the pressing force on the die to the extrusion deforming force are derived. The deforming force is calculated and compared with measured data. The technical and economical efficiency achieved by the die set for producing three-way joints is described.     

40MN 锻压机模架的制造

针对锻压机模架制造过程中所遇到的困难,采取了一系列工艺措施。     

Effect of crystallization conditions of pulse die forging on structure formation in TiAl-and Ti3Al-base alloys

The structure and properties of alloys based on TiAl and Ti₃Al titanium aluminides obtained by the method of pulse die forging are studied. It is shown that the content of aluminum and the changes in the structural factors (the grain size and the width of Ti₃Al lamellas) that control the strength characteristics of TiAl-base alloys with lamellar structure are correlated.