成形冲头

Considering the problems of spurgear precise plastic forming, such as high deformation resistance, poor flowability and especial hardness to fill cant of gear, technological plan was developed based on precise plastic forming technique, successive control principle and consecutive local deformation theory. Moreover, structures of the rolling preform die and the die with up and down wellrounded forcer for stamping-extrusion and bulge-extrusion combining forming were designed too.

因此本文的主要研究内容和结果如下：本文以某种直齿轮：模数m＝2，齿数z＝20，压力角α＝200，变位系数x＝0为对象，针对直齿轮精密塑性成形变形抗力大，流动性差，特别是成形中齿轮角隅部分更加难以充满问题，基于精密塑性成形技术、逐次控制原理以及连续局部变形原理提出了"直齿轮滚轧制坯－镦挤、胀挤复合精成形"的工艺方案，设计了滚轧制坯的模具结构和上下冲头带圆角的镦挤、胀挤复合精成形的模具结构。

At first step, the processor before the deformable body contact the end face of cone die cavity regarded as an extrusion process. The minification of core boss's cross-section regarded as compressibility of direct extrusion, which acted as definition factor when construct the Direct Extrusion Model element. Another step, the model element of flat punch extrusion on wedge piece process was constructed when propose the process of deformable body overflow die corner. In this way the spherical end face of blank looked as cone end face one, t he approximate treatment is one of originality innovation in this paper. At last, the two elements have been connected and constructed the model element of cone boss part's deformation in the open die forging.

对于锥形凸台成形的第一个特征时段，即坯料和锥形凸台型腔的端面接触之前的变形过程，本文将凸台的截面缩小率转换成挤压成形的压缩率并以此为界定，建立了不同截面缩小率时的锥形模正挤压的模型单元；对于锥形凸台成形的第二特征时段即锥形模的角部充满过程，在详细考察锥形型腔端面对变形过程影响的基础上，将变形体的球形端面近似成锥面建立了平冲头挤压楔形体的模型单元；最后将前述两种模型单元有机连结，构建了开式模锻中整个锥形凸台成形过程的定量描述。

But there is a puzzle during forming process, which is that the punch fractures after producing a quantity of the automotive tyre nuts. After choosing other materials for the punch, fretter still happened in the same position of the punch.

但是在成形过程中往往出现一个现象，生产一定数量的工件后，冲头发生断裂，选用不同的材料后，断裂部位仍发生在同一位置。

Using the Updated Lagrange finite element method and the elastic-plastic large deformation finite element formula based on virtual work-rate principle of finite deformation, the author studies in detail the plastic flow rule of MPF, including the influence of the work hardening index, friction, thickness of sheet, material, number and position of the punch.

作者采用逐级更新Lagrange法以及有限变形虚功率增率原理的弹塑性大变形有限元法，详细研究了金属板材多点成形的塑性流动规律，包括加工硬化指数、摩擦系数、板料厚度、材料、冲头个数及位置等对成形的影响，同时探讨了分段成形时的金属流动规律。

By combination of the finite differential technique with the upper bound elemental technique, simulation for the technology of extrusion directly following liquid infiltration which involves infiltration, solidification, and large plastic deformation in one process has been realized and the essences of various technical processes have been revealed by their corresponding simulation results showing the variation of the infiltrated depth and the temperature field with time during infiltration, the punch position, the solidification development of the matrix alloy, the state of the composite within the deforming zone, and the forming load required at different times during extrusion.

采用有限差分法和上限元法相结合，对融浸渗、凝固和大塑性变形为一体的液态浸渗后直接挤压工艺过程进行了数值模拟，从浸渗时浸渗深度与坯料温度场随时间的变化以及挤压过程不同时刻的冲头压下位置、坯料凝固情况、变形区坯料状态、成形载荷大小等方面揭示了不同工艺条件下的各种挤压过程的实质。

Simulation results of initial hole included the relationship of punch load and punch stroke, the hole profile, the distribution of stress and strain, the forming limit diagram, and the variation of the workpiece thickness. The simulation results showed good agreement with the experiments in the bore-expanding process.

由初始孔径4mm之料片於扩孔成形之数值模拟与实验结果比较得知，冲头负荷与冲程关系、内孔轮廓大小、应力与应变分布、成形极限图与工件厚度分布等，皆显示实验与数值模拟间的一致性。

Furthermore, the forming die can realize single punch extrusion according to different die carriers and equipment, double punch extrusion in opposite directions, as well as the extrusion of the helical cylindrical gear with big helix angle.

本发明结构简单，易于制造、安装，可根据不同模架和设备实现单个冲头挤压，也可实现两个冲头对向挤压；可以实现大螺旋角齿轮的挤压；成形力小，下料精度要求低。

The objective of this study was to analyze the square cup stretching process by using the dynamic explicit finite element analytical program, which was based on the Updated Lagrangian Formulation and elasto-plastic theory. Simulation results included the deformation and crack propagation history, the variation of the work piece thickness, the Forming Limit Diagram, and the relationship between punch load and punch stroke. A set of tools was designed for the square-cup stretching experiment to verify the reliability of the program.

中文摘要本文采用显性动态有限元素法，结合材料弹塑性理论，发展出一套三维增量型之有限元素分析程式，进行金属板材方杯拉伸成形制程及破裂之分析，并探讨方杯拉伸成形历程及裂纹成长历程、工件厚度变化、成形极限图(Forming Limit Diagram， FLD)，及冲头负荷与冲程关系，并设计一组方形冲模来进行方杯拉伸成形实验，以验证程式的可信度。

In this paper the forming process in the multi-ram forging process of high-pressure tee joint used in power industry and petroleum chemistry industry is introduced.

介绍了采用多向模锻锻制动力工业和石化工业用高压三通的工艺过程，通过FEM模拟总结出高压三通的基本成形规律，并揭示了高压三通多向模锻过程中水平冲头向上翘曲现象及其产生原因，为类似锻件的多向模锻工艺的设计提供了有益的借鉴。

Considering the problems of spurgear precise plastic forming, such as high deformation resistance, poor flowability and especial hardness to fill cant of gear, technological plan was developed based on precise plastic forming technique, successive control principle and consecutive local deformation theory. Moreover, structures of the rolling preform die and the die with up and down wellrounded forcer for stamping-extrusion and bulge-extrusion combining forming were designed too.

因此本文的主要研究内容和结果如下：本文以某种直齿轮：模数m＝2，齿数z＝20，压力角α＝200，变位系数x＝0为对象，针对直齿轮精密塑性成形变形抗力大，流动性差，特别是成形中齿轮角隅部分更加难以充满问题，基于精密塑性成形技术、逐次控制原理以及连续局部变形原理提出了&直齿轮滚轧制坯－镦挤、胀挤复合精成形&的工艺方案，设计了滚轧制坯的模具结构和上下冲头带圆角的镦挤、胀挤复合精成形的模具结构。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。