不锈钢外板对 2219 铝合金拼焊板胀形性能的影响

目的现有2219铝合金板材宽度不能满足大型复杂曲面件整体流体高压成形需要,仍需采用焊接方法制备成形坯料,焊缝的存在导致铝合金拼焊板整体性能不均匀,影响成形性能及壁厚分布。方法提出2219铝合金拼焊板的双层板流体高压成形方法,采用1.8 mm厚铝合金拼焊板作为内层板,1mm厚不锈钢板作为外层板,进行双层板胀形实验研究。对比分析了单层板与双层板条件下2219铝合金拼焊板的成形极限、应变及壁厚分布。结果外层板的存在能够使板材的极限成形高度和极限应变增加,同时使壁厚分布更加均匀。结论双层板之间存在界面摩擦,可以提高内层拼焊板的成形极限、改善壁厚分布。     

铝合金穿孔装饰吊顶板的吸声特性

铝合金穿条板是现代建筑中一种新型的吊顶及墙面装饰材料，而且还可以组成良好的吸声体，常用于宾馆大堂，机场候机厅，地铁车站，商场，展览大厅，计算机房等建筑。本文介绍了两种吸声结构，在五种空腔条件下的吸声特性，其中包括５００ｍｍ和１０００ｍｍ的大空腔，同时还分析了吸声峰值频率，其预计值和实测值基本相符。     

铝合金板成形性及成形工艺研究现状

介绍了铝合金板材成形过程中影响其成形性能的主要因素,提高铝合金成形性能的先进成形工艺,以及有限元分析技术在铝合金板成形领域应用中的进展.指出开展对高性能铝合金板成形性能的实验研究与成形工艺有限元数值模拟有利于拓宽高性能铝合金板成形件在高技术领域的应用.     

温成形中铝合金板成形极限图的预测研究

在铝合金板温成形数值仿真中,成形极限图是判断材料颈缩失效和评价温冲压成形能力的基础.提出了一种温成形条件下铝合金板成形极限图的理论预测方法.采用曲线拟合方法建立了Al5083-O铝合金板应变硬化指数、应变率硬化指数随成形温度的变化规律;采用M-K理论模型,结合Logan-Hosford屈服函数计算获得温成形条件下铝合金板的成形极限图.计算结果与实验数据吻合较好,证实了温成形条件下铝板成形极限图的理论预测方法是正确的.     

铝合金 2A16 板材成形极限研究

目的掌握硬铝合金在温热条件下的成形性能变化规律。方法采用结合半球凸模胀形和椭圆液压胀形的复合试验法进行了FLD试验,用最小二乘法拟合试验数据,建立了成形极限预测模型。结果试样均在凸模顶端或附近发生破裂,在室温下网格保持较小的圆形,在210℃和300℃下网格被不同程度的拉长和变大,温度对铝合金2A16的成形性能影响很大,随温度升高,成形极限曲线上移。结论复合胀形试验法具有较高的可靠性与准确性;铝合金2A16在高温下成形性能更好;预测模型较好地表述了极限应变值与温度的关系,根据模型可快速得出FLD。     

5042 铝合金板复合拉深工艺下的制耳规律

基于ABAQUS有限元仿真软件,对5042铝合金板在复合拉深工艺下的制耳规律进行了三维数值模拟。通过分析复合拉深工艺中板料成形后的筒高,及厚度、应变的分布规律,探讨了5042铝合金板在这种复合工艺下的成形和制耳规律,揭示了相关塑性变形的机理。     

中间退火对汽车用5182铝合金板组织和性能的影响

采用光学显微镜、扫描电子显微镜、万能力学试验机等测试分析手段,研究中间退火对5182铝合金完全退火态(5182-O)板材组织和性能的影响。结果表明:与未经中间退火的5182-O板材相比,中间退火后的5182-O板材晶粒尺寸过于细小,金属间化合物破碎不充分、尺寸大,弥散析出相数量少;屈服强度、抗拉强度、加工硬化指数和塑性应变比厚向各向异性降低,塑性应变比平面各向异性增大;板材的组织、力学性能和成形性能未获得有效改善和提高。     

高品质铝合金汽车板预处理气垫炉技术

首先介绍了铝带预处理的原理、工艺特点及气垫炉的工作原理,研究了汽车板生产工艺流程中的难点和重点,指出了气垫炉的工艺位置和不可替代的重要作用;回顾了铝带气垫炉生产线的发展过程,并对其进行了阶段划分和总结;分析了铝带气垫炉的研究现状,对其关键技术进行了深入分析,提出了铝合金汽车板气垫炉技术今后在工艺、设备及控制模型方面的研究重点。随着汽车行业轻量化的快速发展,汽车用铝带气垫炉装备、生产工艺技术的研究与开发必将迎来一个新的发展阶段。     

铝合金汽车板罗平线的影响因素

阐述了铝合金板材罗平线的产生原因、检测方法及操作步骤。通过拉伸试验、弯曲试验分析了影响罗平线的因素。结果表明:铝合金板材的各向异性、弯曲角度、表面状态对罗平线均有一定影响;严格控制热轧的开轧温度和终轧卷曲温度是保证铝合金汽车板罗平线合格的有效途径。     

5A06 铝合金板材超塑气胀成形数值模拟

目的改善5A06铝合金板材超塑性气胀成形件壁厚分布。方法采用MARC有限元分析方法,对商业供货态5A06-O铝合金板材(原始厚度为2 mm)的超塑性成形进行数值模拟分析。结果优化后的反吹预减薄变形,使杯形件最终壁厚分布大大改善,最薄处壁厚从单纯正吹胀形时的0.65 mm提高到了0.94 mm,壁厚均匀性指数达到0.079。结论合理的反胀形模具可以增加最小壁厚,达到提高壁厚均匀性的目的。     

控制压边力改善铝合金板成形性能的研究

以5052H32铝合金板为研究对象,以有限元数值模拟和基于计算机控制多点变压边力液压压力机的实验为手段,研究随位置变化的压边力对铝合金板成形性能的影响.研究结果表明:合理地控制随位置变化的变压边力可以显著提高铝合金板的成形性能,增加盒形件的拉深深度(最大拉深高度提高约12%);随位置变化的压边力对铝合金成形性能改进的主要原因是减少破裂危险区域壁厚减薄和应变的峰值;采用Barlat 96屈服准则描述铝合金的屈服行为具有较高精度,数值模拟和实验的偏差较小.     

铝合金汽车板性能及其应用

深入讨论了预处理工艺的影响并说明了该工艺在保证铝合金汽车板使用性能的重要性。介绍了铝合金汽车板在汽车上的典型应用。基于笔者认识和目前的研究进展,提出了汽车用铝合金汽车板的重点研发内容,降低成本和价格,做好应用研究是扩大铝合金汽车板在汽车上应用的重要工作。     

Improvement in formability of aluminum alloy sheet by enhancing geometrical hardening

Individual grains in a polycrystal rotate during plastic deformation. This leads to a change in the crystallographic texture, and results in an increase or decrease of the macroscopic flow stress of the material. Such a change of strength as a result of grain rotations is called geometrical or texture hardening/softening. In the present study, for textured aluminum alloy sheets, the geometrical hardening/softening effect in the in-plane plane-strain stretching mode is numerically investigated using a generalized Taylor-type polycrystalline model. It is found that the cube texture () exhibits significant geometrical hardening when the major stretching direction is inclined at 45° relative to the orthotropic axes, and that a cube texture rotated about the normal direction (ND) shows a notable degree of geometrical hardening for any in-plane orientation of the sheet. Using the Marciniak-Kuczyński-type approach, forming limits for these textured sheets are analyzed. It is found that geometrical hardening definitely enhances the formability. It is, therefore, strongly suggested that texture control guided by the present results may be highly effective in producing aluminum alloy sheets with higher formability.     

Influence of cold-rolling and annealing conditions on formability of aluminium alloy sheet

Using an Al-Mg-Cu alloy developed for auto body panels, strip sheets are experimentally produced by various cold-rolling and annealing procedures. Tensile and metallographic properties of the sheets and their relations are examined to attain high formability. The elongation is closely related to the grain size, and increases with the final annealing temperature. The rolling texture influences the plastic anisotropy, the Lankford value of the sheets. The comparatively high Lankford values are obtained under the condition that both the intermediate and the final annealing temperatures are higher and the reduction ratio after the intermediate annealing is smaller.     

Microstructure and press formability of a cross-rolled magnesium alloy sheet

Cross-rolling, in which the roll axis is tilted by 7.5° towards the TD-direction, was carried out on a commercial magnesium alloy. The (0002) texture intensity of the cross-rolled specimen was lower than that of the unidirectionally rolled specimen, and the (0002) texture of the cross-rolled specimen was inclined about 10° towards the TD-direction. Also, the grain size of the cross-rolled specimen was smaller than that of the unidirectionally rolled specimen. As a result of the Erichsen tests at 433-493 K, the press formability of the cross-rolled specimen was higher than that of the unidirectionally rolled specimen. The high formability of the cross-rolled specimen is attributed to both the modification of (0002) texture and the enhancement of grain refinement by the cross-rolling.     

聚碳酸酯合金板的性能研究

研究了新开发的铁路客车用聚碳酸酯合金板 (商品名称Polyshet)的光老化性能、热老化性能、阻燃性能、冲击性能及表面硬度 ,并与PC/ABS合金板作了性能对比。     

AZ31镁合金非等温拉深性能的研究

针对AZ31镁合金等温拉深性能差的问题,提出了AZ31镁合金的非等温拉深工艺.通过平底杯形冲头拉深试验研究了不同冲头温度和板料温度对AZ31镁合金非等温拉深性能的影响,确定了使AZ31镁合金具有最佳拉深性能的板料和冲头温度范围.实验结果表明,除了板料和冲头温度之外,拉深速度和润滑条件对AZ31镁合金的非等温拉深性能也有重要影响.     

铝网架结构的研究与工程应用

为了研究铝合金箱型-工字型盘式节点单肢构件在竖向和侧向力作用下的受力性能,该文以足尺试件的静力加载试验为基础,采用通用有限元分析软件ABAQUS对铝合金箱型-工字型盘式节点单肢构件进行非线性有限元分析,同时将该盘式节点与刚性节点受力性能进行对比。有限元分析结果表明：在竖向荷载作用达到极限时,试件DZ1的长肢箱型杆件与节点盘相连处的腹板以及下翼缘发生局部屈曲,试件DZ3的紧邻长肢工字型杆件的短肢箱型杆件腹板进入塑性;在侧向荷载作用达到极限时,试件DZ2、DZ4均表现为长肢杆件与节点盘连接处最外侧铆钉孔断裂破坏。有限元模拟结果与试验结果拟合较好,节点较刚性节点应力分布相似,该种混合型盘式节点具有较高的刚度,可作为半刚性节点应用于实际工程当中。     

Rotation friction pressing riveting of AZ31 magnesium alloy sheet

A kind of joining method for magnesium alloys, rotation friction pressing riveting (RFPR), is proposed in this paper. In RFPR operation, a rivet with a plug rotating at high speed is brought to contact with the riveted sheets, generating frictional heat between the rivet and riveted sheets, which softens the sheet materials and enables the rivet to be drilled into the sheets under reduced force. When fully inserted, the rivet is stopped rotating, and the plug is immediately pressed into the shank of the rivet by a punch. The expansive deformation of the rivet shank occurs under the action of the plug, thereby forming a mechanical interlock between the rivet and the sheets to fasten the sheets together. The studies show that RFPR of AZ31 magnesium alloy sheet can be carried out at ambient temperature, and provides the joints with superior shear strength and fatigue property when compared with self-piercing riveting (SPR). The effects of the operating parameters of RFPR process on the quality of the joints were investigated in the study. The results shows that while the rivet rotation speed little affects the shear strength of RFPR joints, the punch pressure has a significant influence on the mechanical properties of the RFPR joints. A numerical analysis was also performed to understand the effect of the punch pressure on the interlock between the rivet and the sheets, and the stress and strain distribution inside the sheet materials around the rivet. The results show that the interlock increased with the punch pressure and there is residual compressive stress inside the sheet materials, which seems to explain the good fatigue property of RFPR joints observed.