高分子薄膜润滑在板料拉深中的应用研究与发展趋势

介绍了高分子薄膜润滑在板料拉深中的应用研究与发展趋势,分别从高分子摩擦润滑的机理、板料成形中高分子薄膜的润滑工艺以及高分子润滑材料的摩擦学研究3个方面概述了目前高分子薄膜润滑的研究及应用现状、高分子润滑剂的润滑特点,简述了高强度钢板拉深成形中存在的问题和高强度钢板成形时采用高分子薄膜进行润滑会获得良好的成形性能,并指出高分子薄膜润滑存在的问题和发展趋势。     

热固树脂－K08Al钢层状复合板的成形性及减振性

研究了由几种不同基团比和的热固性树脂与Ｋ０８Ａｌ薄钢板组成的层状复合板的力学性能、成形性及减振性。结果表明，仅用应变硬化指数ｎ值和塑性应变比ｒ值不足以充分评定复合钢板的成形性。在复合钢板设计时应考虑到表皮钢板应具有良好的成形性，其间的粘接强度应超过１３ＭＰａ复会钢板的使用温度在其夹层材料的玻璃化温度约±１５℃内可获得最佳减振性能。     

表面处理钢板的镀层和成形性能

近年来,用户对汽车和家用电器的耐蚀性要求更强烈。在这些产品中,表面处理钢板的使用比例迅速增加。随之,冲压加工中的镀层剥离问题,普通钢板、表面处理钢板及不同种类的表面处理钢板.在冲压成形性方面的变化问题也日渐突出。有关表面处理钢板冲压成形性能变化的原因人们已作了许多研究,认为有两种因素。其一是镀层引起钢板材料特性值变化;其二是镀层种类不同,润滑性各异。本文将介绍普通钢板和表面处理钢板的冲压成形性羞异,以利于表面处理钢板的正常使用。     

新型钢板成形模顶杆结构的应用

对汽车冲压生产中钢板成形模具顶杆结构的形式进行了阐述,重点介绍了常规钢板成形模顶杆结构和新型钢板成形模顶杆结构的特点和工作原理,对钢板成形模顶杆结构的选用有一定的参考意义.     

高强汽车板成形技术及轻量化

应用高强钢板是汽车减轻质量、提高安全性的基础.本文分析了高强钢板的种类及冶金特点,并详述了高强钢板冷成形的工艺特点及缺陷防止措施和热成形的关键工艺技术,及其在典型汽车结构件上应用,为汽车制造业的轻量化和实用化研究提供了理论依据和指导.     

高强度钢板在汽车冲压生产中的应用

对汽车冲压生产中高强度钢板的应用进行了阐述。介绍了高强度钢板的性能,分析了因回弹、侧壁翘曲、扭曲和棱形翘曲原因而产生的高强度钢板产品尺寸精度问题,提出了通过产品设计、冲压工艺和模具结构设计以及模具调试来控制高强度钢板尺寸精度。介绍了高强度钢板模具材料的选用以及热成形技术。     

主应变分析在成形零件边部开裂中的应用

介绍了冲压CAE中主应变分析在解决高强度钢板成形零件边部开裂问题的应用,探讨了采用主应变分析数值评判高强度钢板成形边部开裂的可行性,常规冲压CAE评判指标(变薄率等)不能作出准确评判。为解决该问题,结合材料延伸率,利用主应变分析数值评判高强度钢板成形零件边部开裂的风险,并在实际模具开发中进行了验证。     

成形速度及载荷对高强钢板回弹影响的研究

回弹问题一直是高强钢板弯曲成形的难点。本文基于伺服压力机对成形速度、载荷以及滑块行程的可控性,通过控制高强钢板弯曲成形过程中的成形速度、载荷以及滑块的行程位移,在试验的基础上探讨了成形速度及载荷等工艺条件对高强钢板弯曲回弹的影响,并通过ABAQUS有限元软件进行了相关的成形模拟。研究结果表明,随着成形载荷的增大回弹量明显减小,多次折弯可有效减小回弹。另外,成形速度和凸模保压时间对回弹影响不大。因此,在伺服压力机工作环境下,可以通过精确控制成形载荷以及折弯次数来控制高强钢板弯曲回弹量。     

汽车超高强钢热冲压成形新工艺——选择性冷却

超高强钢板热成形作为汽车制造领域的热门技术,在轻量化、节能减排和提高安全性等方面发挥了重要作用,具有广阔的应用前景.综述了国内外对热成形工艺的研究状况,然后提出一种新的热成形工艺——选择性冷却,重点介绍了该工艺的基本原理,指出了该工艺的研究内容及目前存在的关键问题.最后陈述了其应用前景.     

人工神经网络在塑性成形领域中的应用研究

在概述人工神经网络发展及应用的基础上,综述了国内外神经网络在塑性成形领域中应用的现状,着重介绍了板材成形和模具设计与制造方面应用神经网络的现状。利用人工神经网络实现了板材拉深成形智能化控制过程中摩擦系数的实时识别,并对其进行了实验证,结果表明,神经网络模型能够很好地解决板材拉深成形智能化控制过程中摩擦系数的实时识别问题,实现整个拉深化过程的智能化控制。最后指出了当前人工神经网络研究与应用中的不足之处及今后的研究方向。     

燃油箱用无铅表面处理钢板材料的发展

镀铅锡合金钢板是传统的汽车燃油箱钢板材料,但由于人们环保意识的增强,燃油箱无铅化已是大势所趋.发达国家的许多钢铁厂开发了各种无铅且耐蚀性更好的汽车燃油箱用表面处理钢板材料,包括无铅镀层钢板和预涂层钢板两大类.热浸镀Al钢板、热浸镀Zn-Sn钢板、电镀Zn-Ni钢板、热镀Zn闪镀Ni双层镀钢板等无铅镀层钢板和预涂层GA钢板、预涂层电镀Zn-Ni钢板等预涂层钢板都已在汽车上应用.具有优良耐蚀性、成形性和焊接性的无Pb、无Cr(VI)预涂层钢板已成为汽车燃油箱钢板发展的方向.     

Processing and properties of ultrafine-grain aluminium alloy 6111 sheet

The equal channel angular processing (ECAP) technique has been applied to an automotive aluminium alloy sheet (A6111). The technique utilizes a machine that was specially designed for this purpose at Monash University. It was determined that ECAP is able to refine the grain size of the sheet, diminish the detrimental as-rolled texture components in the sheet and retain an acceptable level of bi-axial ductility such as is required during the automotive forming process. Experiments were carried out on annealed, as-received sheets that were subjected to either one or two passes through the ECAP machine. For the second ECAP pass, the sheet could be processed in the same orientation as the first pass (route A) or it could be rotated 180° about the direction of feeding (route C). It was determined that route A produced marginally improved properties compared to sheet processed via route C, and that due to the frictional heating generated during the second pass, a significant amount of recovery occurred in the sheet such that an improved combination of texture and formability resulted after two passes compared to the same sheet exposed to only a single pass.     

先进制造技术在汽车覆盖件模具制造中的应用

汽车覆盖件的成形工艺和模具制造技术是先进制造技术的重要组成部分,以高强度钢板为代表的新材料在汽车行业的广泛应用对汽车覆盖件模具制造业带来了新的挑战,该文从汽车覆盖件模具的设计、制造、仿真分析、制造信息化技术几个方面综合阐述了先进制造技术在模具设计制造过程中的应用。     

Overview of superplastic forming research at ford motor company

In an effort to reduce vehicle weight, the automotive industry has switched to aluminum sheet for many closure panels. Although the application of aluminum is compatible with existing manufacturing processes and has attractive qualities such as low density, good mechanical properties, and high corrosion resistance, it has less room-temperature formability than steel. The expanded forming limits that are possible with superplastic forming can significantly improve the ability to manufacture complex shapes from materials with limited formability. Aluminum closure panels produced by superplastic forming have been used by Ford Motor Company for over a decade. However, applications have been limited to low-volume, specialty vehicles due to the relatively slow cycle time and the cost penalty associated with the specially processed sheet alloys. While there has been substantial research on the superplastic characteristics of aluminum alloys, the bulk of this work has focused on the development of aerospace alloys, which are often too costly and perhaps inappropriate for automotive applications. Additionally, there has been a limited amount of work done to develop the technologies required to support the higher production volumes of the automotive industry. This work presents an automotive perspective on superplastic forming and an overview of the research being performed at Ford Motor Company to increase the production volume so superplastic forming can be cost competitive with more traditional forming technologies. This paper was presented at the International Symposium on Superplasticity and Superplastic Forming, sponsored by the Manufacturing Critical Sector at the ASM International AeroMat 2004 Conference and Exposition, June 8–9, 2004, in Seattle, WA. The symposium was organized by Daniel G. Sanders, The Boeing Company.     

薄板冲压大变形起皱的局部无网格法数值模拟

以有限元理论及方法为基础的CAE技术在冲压工艺分析中发挥了巨大作用,解决了许多以前靠解析方法和实验无法深入研究的问题。但是由于单元网格带来的一些缺陷,在模拟形状、边界条件复杂的板料冲压过程时遇到了困难。文章针对有限元方法在板料冲压大变形起皱情况下数值模拟的不足,研究局部无网格法计算,即在发生起皱大变形区域采用无网格伽辽金方法,其他区域仍用有限元方法,有效地平衡了计算精度与计算效率的矛盾。通过算例分析效果很好,对于提高冲压CAE软件的实际应用能力有重要意义。     

Prediction of forming limit curve for pure titanium sheet

Commercially pure titanium (CP Ti) has been actively used in the plate heat exchanger due to its light weight, high specific strength, and excellent corrosion resistance. However, researches for the plastic deformation characteristics and press formability of the CP Ti sheet are not much in comparison with automotive steels and aluminum alloys. The mechanical properties and hardening behavior evaluated in stress–strain relation of the CP Ti sheet are clarified in relation with press formability. The flow curve denoting true stress–true strain relation for CP Ti sheet is fitted well by the Kim–Tuan hardening equation rather than Voce and Swift models. The forming limit curve (FLC) of CP Ti sheet as a criterion for press formability was experimentally evaluated by punch stretching test and analytically predicted via Hora's modified maximum force criterion. The predicted FLC by adopting Kim–Tuan hardening model and appropriate yield function shows good correlation with the experimental results of punch stretching test.     

锌层对电镀纯锌钢板成形性能的影响研究

分析电镀锌钢板的成形特性,包括镀层对力学性能和成形极限的影响,镀层损伤行为以及摩擦系数和润滑剂粘度的关系等。结果表明,电镀纯锌层对钢板的力学性能和成形极限影响很小。随着运动粘度的增加,电镀锌钢板的摩擦系数逐渐降低。与合金化镀层相比,电镀纯锌镀层更易随基板变形,因此表面裂纹出现较晚且数量较少。     

涂装板料的对向液压成形工艺研究

涂装板料是航天航空与汽车制造等领域广泛应用的一种新型材料,采用传统成形工艺将破坏其表面涂层和光泽,并且影响成品质量.因此,涂装板料的成形一直是一个难题.本文采用对向液压成形法来解决该问题.以高速列车车门成形为例,使用FASTAMP软件辅助工艺规划.     

基于Abaqus的汽车板快速冲压有限元分析

基于Abaqus/Explicit动力显式有限元方法,分析了不同冲压速度下的某汽车覆盖件在冲压成形过程中节点速度、应变速率的分布规律.结果表明:随着冲压速度的提高,在变形过程中节点速度基本呈现增高的趋势,特别是变形较复杂的区域.同时,指出为了能更准确地模拟实际冲压过程,有限元材料模型中应采用应变速率大于10-2 s-1获得的力学性能参数进行研究,以便更准确地反映实际材料特性.