曲轴TR镦锻模具CAD／CAE系统开发与应用

开发了一个曲轴TR镦锻模具CAD／CAE系统,该系统的功能包括锻件设计、毛坯设计、模具设计、图纸输出以及与CAE软件的接口。介绍了系统开发的流程及方法。系统开发的关键技术包括建立参数化图库、图形自动绘制和成形过程模拟等。作为应用实例,采用该系统完成了某型号曲轴的全部设计流程,通过对曲轴锻造过程的有限元模拟优化了毛坯尺寸,从而验证了系统的可行性。     

锻坯/模具界面摩擦对汽轮机叶片模锻成形的影响

汽轮机叶片是将蒸汽能转换成机械功的关键部件,叶片精锻是叶片锻造的发展趋势.本文利用数值模拟方法,仿真了叶片金属在锻模型腔内的流动和成形过程,论述了摩擦条件对叶片精锻成形规律的影响.在锻坯金属变形充模的3个阶段,分析并讨论了不同的界面摩擦因子m对叶片模锻成形规律和模具失效的影响.数值实验结果表明:随着界面摩擦因子的增加,克服坯料金属界面流动阻力所需的附加模锻载荷增加,叶片锻件不同区域内的最大最小温度差、最大最小等效应变差,以及最大最小等效应力差增加;与此同时,锻模型腔局部最大等效应力和最大温度也增加.     

汽车前轴精制坯辊锻工艺及模具设计

根据汽车前轴锻件的特点、技术条件与要求，分析了前轴辊锻工艺的难点，包括确定辊锻件图，选择毛坯尺寸，确定辊锻，典型截面特征孔型设计，计算前滑量并分析其对锻件长度的影响。本文以NHR前轴为例，进行了精密辊锻制坯工艺及模具设计的研究，设计出前轴制坯辊锻、预成型辊锻和终成型辊锻模具。     

精密锻造及其模具设计与制造技术

本文概括地描述了现代工业中精密锻造生产的现状 ,并就精锻用材料、设备以及支撑精密锻造的关键技术———锻造工艺设计及模具制造技术 ,进行了简单的回顾。就所研究开发的“实用锻造工艺设计辅助系统”做了介绍 ,该系统由 4个模块组成 ,对工艺设计人员有参考价值。最后探讨了精锻技术的研究动态     

摩擦压力机上套锻工艺的研究

针对环类锻件与饼类锻件的特点进行工艺分析,给出了一套实用的前挡与后盖的摩擦压力机的套锻工艺.该工艺主要利用上模的凸模作为冲孔凸模,冲出的落料作为锻造后盖用,周围留下的材料则作为锻造环类锻件前挡用,该锻件在压力机的打击下在模具内成形.该工艺不仅降低劳动成本,节约冲孔连皮钢材,减少下料环节,同时,简化了切边模具结构.     

基于响应面法的机动车尾气后处理系统铝泵体的精锻工艺优化

针对机动车尾气后处理系统铝泵体精锻过程中出现的锻件凸台充填不完整、模具易开裂和飞边废料多等问题,建立了以锻件凸台端面充填率、终锻力比率和材料利用率为优化目标,以模具预热温度、坯料长度、坯料加热温度和飞边桥部高度为设计变量的二次多项式响应面模型。然后结合响应面法与差分进化算法对锻造参数进行优化,得到的最优锻造参数为:模具预热温度为350℃,坯料长度为83. 27 mm,坯料加热温度为490℃和飞边桥部高度为1. 15 mm。最后,采用最优锻造参数进行实际生产,生产出的锻件充填完整,提高了模具寿命和材料利用率。     

摩托车齿坯闭式温精锻模具及工艺

介绍了摩托车齿温精锻工艺及模具,针对精锻用模具在成形过程中的失效形式,经过对模具等效应力场的数值分析,给出了一种新的镶块模具结构,使其模具寿命大幅度提高,降低了摩托车齿坯的锻造成本。     

基于UBET和FEM的模锻件预成形设计

提出了一种用于锻造过程预成形模拟设计的新方法——基于 U BET和 FEM的混合正 /反向模拟预成形设计技术 ,即先用 UBET进行反向模拟 ,快速找出可能的预锻件或初始坯料 ,再用 FEM进行正向模拟验证 ,必要时可根据正向模拟结果对坯料或预锻件进行修改 ,使之能够达到完全充满型腔且飞边尽可能小的最佳效果。应用 U BET和FEM的混合正 /反向模拟预成形设计技术进行预成形设计 ,并与实验结果进行对比 ,结果与实测值基本吻合。     

YQ153A前轴精密辊锻工艺实验与结果分析

介绍了YQ153A前轴精密辊锻工艺实验与结果分析。通过工艺实验,解决了弹簧板展宽不够,厚度不足,折叠,刮料等问题,工字截面充不满和上下成形不对称的问题,第1道辊锻件弯曲,第2、3道辊锻件倒料等影响稳定性的问题,并按实际情况分道次对辊锻模中段减短,可得到理想的前轴精密辊锻件。     

数值模拟技术在汽轮机叶片模锻成形中的应用

有许多因素影响汽轮机叶片的模锻生产质量,例如,材料性质、毛坯外形及尺寸、模锻方式及工艺、模腔结构与锻压设备等.本文针对某汽轮机叶片的模锻生产,应用数值模拟技术,分析和探讨了改进模锻工艺、提高产品质量、防止模具过早失效的途径.模拟结果与生产实践表明:在保证坯料金属完全充满模腔并压实的前提下,适当减少锤击次数,既能降低模具损坏几率,又可节约锻打能源;尽量采用较大的过渡圆角半径,以便抑制模锻叶片根部折叠等缺陷的产生;界面润滑有利于模锻叶片成形;模具型腔局部高温和高应力的交互作用是造成模具过早失效的重要原因.     

航空叶片精锻模具优化设计

针对我国航空叶片精锻模具设计效率低、某些设计参数确定困难等问题。在对航空叶片精锻工艺技术分析的基础上,开发了参数化CAD模锻系统,实现了航空叶片精锻模具及锻坯的自动化生成,提高了叶片模具设计自动化水平;运用Deform-3D软件对整个精锻工艺过程进行模拟仿真,分析了不同设计参数下锻件与模具的应力分布、横向错模力、模具磨损等,得出了有益于叶片成形和延长模具寿命的设计参数,并对其参数设计规则进行了优化;进行了锻造实验,分析了锻件的几何尺寸精度,为航空叶片精锻模具设计参数选择提供了理论指导。     

Microstructure optimization in design of forging processes

A new approach based on sensitivity analysis for optimizing the microstructure development during the forging processes is proposed in this work. The analytical sensitivities of the recrystallization volume fraction and dynamically recrystalized grain size with respect to the design variables are derived. The mean grain size in each finite element is introduced so that the complex recrystallization mechanics, such as no recrystallization, partial recrystallization and complete recrystallization are all considered. The objective is to minimize a function describing the variance of mean grain size and the average value of mean grain size in the whole final product. Two constraints are imposed on die underfill and excessive material waste. Two different kinds of design variables are considered, including state parameter (initial shape of billet) and process parameter (die velocity). The optimization scheme is demonstrated with the design of a turbine disk made of Waspaloy in non-isothermal forging process. The optimal initial shape of billet and the die velocity are obtained.     

Application of neural network and FEM for metal forming processes

This paper proposes a new technique to apply the artificial neural network in metal forming processes. A three-layer neural network is used and a back propagation algorithm is employed to train the network. It is determined by applying the ability of function approximation of the neural network to the initial billets which satisfy the minimum of incomplete filling in the die cavity. The die geometry for cylindrical pulley is designed to satisfy the design conditions of the final product. The proposed schemes have been successfully adapted to find the initial billet size for axisymmetric rib-web product and to design the die geometry for cylindrical pulley. The neural network may reduce the number of finite element simulation for designing the die of forging products and further it is usefully applied to multi-stage process planning.     

STUDY ON THE NUMERICAL SIMULATION OF MULTI-STAGE ROTARY FORGING OF A NON-AXISYMMETRIC PART AND THE CAE ANALYSIS OF THE DIE STRENGTH

Traditionally a rotary forging process is a kind of metal forming method where a conic upper die, whose axis is deviated an angle from the axis of machine, forges a billet continuously and partially to finish the whole deformation. For the rotary forging process simulation, more researches were focused on simulating the simple stage forming process with axisymmetric part geometry. Whereas in this paper, the upper die is not cone-shaped, and the billet is non-axisymmetric. So the movement of the punch is much more complicated than ever. The 3D FEM simulation models for the preforming ＆ final forming processes are set up aider carefully studying the complicated movement pattern. Deform-3D is used to simulate the material flow, and the boundary nodal resisting forces calculated by the final stage process simulation is used to analyze the final forming die strength. The CAE analysis of the die shows that the design of the final forming die is not reasonable with lower pre-stress which is easy to crack at the critical corners. An optimum die design is also provided with higher pre-stress, and verified by CAE analysis.     

基于数值模拟的前轴辊锻件精确成形的研究与应用

根据辊锻设计要求,论述了汽车前轴辊锻件的弹簧座截面、工字型截面、两端拳头截面各道次变化规律;在各道次变化过程中,依据各截面的尺寸参数变化对辊锻模具进行精确设计并选择合理的坯料,以保证坯料能够充满模具型槽.应用Deform-3D软件对辊锻模具模型进行模拟分析,模拟结果与实际生产结果相吻合,进一步验证了辊锻模具设计的准确性和可靠性.该文的论述对前轴辊锻模具的精确设计及辊锻件的生产提供了理论参考依据.     

A study on a thixoforming process using the thixotropic behavior of an aluminum alloy with an equiaxed microstructure

Alloys with an equiaxed microstructure exhibit significantly lower flow resistance in the semisolid state than alloys with a dendritic microstructure. Their thixotropic behavior (solidlike in the unperturbed state and liquidlike during shearing) has been the basis for a thixoforming process. It is accepted today that thixoforming is a new net-shaped manufacturing technology in which the billet is heated to the semisolid state with coexisting solid-liquid phases. The thixoforming process has some industrial advantages, such as the successful fabrication of high-quality components with fewer inner defects, suitable for less machining, high productivity comparable to high-pressure die casting, and being an energy-saving system without the conventional melting process. It consists of inductive coil design, a billet reheating process, billet handling, filling into the die cavity, and solidification of the thixoformed part. This work presents an overview of all the detailed stages in the thixoforming process to manufacture the net-shaped product with good mechanical properties. An air compressor part with high strength has been fabricated by the thixoforming process.     

异形触指冷镦成形工艺及模具结构

通过对异形触指的成形工艺及模具结构分析,提出了该零件成形时存在的问题及比较合适的毛坯形状,并用Defom-3D进行数值模拟,为类似零件的冷锻成形探索了一条行之有效的途径.     

国内外摆动辗压技术的研究和发展

介绍了摆动辗压成形技术在美国、英国、波兰、前苏联、瑞士、日本和德国等工业发达国家的研制和生产概况。综述了我国科技工作者在摆动辗压机的机身设计计算与制造、摆头的设计计算、摆动辗压的运动轨迹以及摆动辗压成形过程中坯料与摆头之间的接触情况等;在摆动辗压成形过程中的应力、应变分布的实验研究与数值模拟分析,缺陷形成机理分析,以及摆辗变形力的工程计算等;热摆动辗压成形工艺、温摆辗成形工艺和冷摆辗成形工艺在汽车、摩托车、五金工具和兵器工业等加工制造业的工程应用等方面所作的成形机理、数值模拟、设备和工艺研究情况。     

自由锻锤上冷冲厚板新工艺

介绍了自由锻锤上冷冲厚板工艺的特点和模具主要结构，以及如何解决凸凹模间隙选用小间隙冲孔时刃口磨损加剧的问题。研制出了降低磨损，提高模具寿命的润滑剂配方。设计了适合自由锻锤上厚板冲孔的模具，对在自由锻锤上厚板冲孔进行了有益的尝试,扩大了自由锻设备的加工范围，解决了不具备大型压力机情况下的生产难题。     

自由锻锤上冷冲厚板新工艺

介绍了自由锻锤上冷冲厚板工艺的特点和模具主要结构,以及如何解决凸凹模间隙、选用小间隙冲孔时刃口磨损加剧的问题。研制出了降低磨损,提高模具寿命的润滑剂配方。设计了适合自由锻锤上厚板冲孔的模具,对在自由锻锤上厚板冲孔进行了有益的尝试,扩大了自由锻设备的加工范围,解决了不具备大型压力机情形下的生产难题。