薄板铝合金的TIG拼焊及其单向拉伸成形性能

拼焊所具有的优点使其成为绿色再制造技术之一。本文首先针对汽车轻量化材料铝合金薄板制定焊接工艺、优化焊接参数,实施TIG拼焊,并对铝合金TIG拼焊板进行微观组织、显微硬度、单向拉伸成形性能测试及扫描电子显微镜断口形貌测试,同时分析了焊接接头组织及硬度分布规律、焊缝位置对铝合金拼焊板成形性能的影响。研究表明:焊缝组织是细小的等轴晶和树枝状晶,硬度较低;焊缝的位置不同,拼焊板的成形性能不会有明显差异;试样的断口形貌表明6061铝合金拼焊板的塑性低于母材。     

汽车用铝合金拼焊板技术研究现状

剪裁拼焊板是将不同材质、不同厚度的板料经剪裁后,用激光焊接拼成各种坯板,然后整体冲压成形的一种新技术。剪裁拼焊钢板在汽车工业中的应用,取得了很大的经济效益,而铝合金激光剪裁拼焊板技术尚未得到应用。在分析剪裁拼焊板技术的主要优点及其在汽车工业中的应用现状及汽车车身材料发展趋势的基础上,论述了汽车车身用铝合金激光剪裁拼焊板的可用材料及其激光加工技术,并预测了铝合金激光剪裁拼焊板在汽车工业中的应用前景。     

基于侧面碰撞特性的B柱总成轻量化设计分析

基于侧面碰撞吸能特点,对B柱总成进行轻量化设计。从材料、工艺、结构等方面入手,对原B柱外板和加强板进行轻量化设计,采用热成形材料替换、增加补丁板和激光拼焊等3种方案进行设计,采用侧面碰撞仿真分析对方案进行可行性验证,并将设计方案综合应用到实际车型中对方案进行检验。结果表明:3种方案均可实现轻量化设计;热成形材料替换方案的最大侵入量和侵入速度最优,材料的碰撞安全性最高;在满足碰撞安全性的前提下,激光拼焊方案和热成形材料替换方案的轻量化效果基本相当,所研究的案例轻量化效果达到减重16%左右;综合应用分析方案,在满足碰撞安全性法规的前提下,实现减重20%,同时仿真与试验误差控制在15%以内,表明研究结果可以应用于实际车型设计。     

轻量化汽车用拼焊板冲压成形性能研究现状与展望

针对目前轻量化汽车用的拼焊板冲压成形性能进行了综述,从拼焊板成形性能研究的试验方法、相关试验标准,影响拼焊板成形性能的非线性因素、分类标准以及拼焊板成形性能研究的困难和未来挑战等方面展开论述,力求为拼焊板的成形性能研究及拼焊板的应用提供一定的理论参考。     

基于Norton-Hoff粘塑性理论的铝合金拼焊板成形性能预测与实验研究北大核心CSCD

铝合金拼焊板是汽车轻量化技术的重要发展方向之一,其成形性能是关键的性能指标参数。采用基于Norton-Hoff粘塑性理论的有限元方法,模拟了AA5754铝合金拼焊板极限拱顶高度实验的成形过程。分析了成形高度分别为20和29 mm时,铝合金拼焊板中应变和位移的分布情况,预测了AA5754铝合金拼焊板的成形性能。在极限拱顶高度实验中,等效应变沿着成形轮廓线路径呈M形对称分布,最大等效应变出现在冲头与板材接触的边缘位置。有限元预测结果与实验结果有着较好的吻合度,极限拱顶高度实验得出,铝合金拼焊板的LDH值为29.5 mm,断裂位置位于冲头与板材接触的边缘。     

车门不等厚拼焊板冲压成形关键技术

拼焊板成形技术的研究背景随着汽车工业的飞速发展，国家和社会在汽车安全、环境保护，节约能源等方面对汽车工业提出了更高的要求。在车身制造中，采用不等厚激光拼焊板具有减轻车身重量，减少零件数量，提高安全可靠性及降低成本等诸多优点，因此已经成为汽车轻量化发展的主要方向，对不等厚料的拼焊板成形技术进行研究，其技术背景有两方面。     

变截面薄板在车身制造中的应用研究

分析了汽车轻量化的技术内涵和主要途径,指出在车身制造中采用变截面薄板是汽车自身减重且能够提高汽车性能的有效措施.重点介绍了激光拼焊板和柔性轧制技术,着重讨论了连续变截面辊轧板(TRB)在汽车轻量化中的应用,并给出了TRB在车身制造应用中尚需深入研究的重点.     

铝合金拼焊板充液成形技术研究

铝合金拼焊板充液成形技术是拼焊板成形技术和充液成形技术的综合运用,兼具了这2种先进成形技术的双重优点,在汽车、航空航天等领域具有广泛的应用前景。介绍了铝合金拼焊板焊接方法、激光焊接的特点与难点,探讨了拼焊板充液成形技术的原理、特点及国内外研究现状,指出了开展此项研究的必要性和重要意义。     

5A06-O铝合金蒙皮的拼焊工艺

分析了4mm铝合金板5A06-O拼焊的焊接工艺特点，从焊前准备、焊接方法、焊接材料、焊接规范、焊后检查以及缺陷补焊等方面进行试验分析，确定了4mm铝合金板5A06-O的拼焊工艺，保证了铝合金顶盖蒙皮拼焊的焊接质量，满足出口电力机率的设计要求。     

激光拼焊技术在汽车工业中的应用

介绍了在汽午工业中使用激光拼焊板及激光拼焊管的情况.激光拼焊技术即将两块或多块具有不同厚度的材料通过激光焊接方法焊接起米再予以成形.目前激光拼焊产品包括激光拼焊板及激光拼焊管.汽车工业通过使用激光拼焊技术可以在实现减重的同时提高安全性,同时通过使用激光拼焊技术.使材料也得剑了合理利用并且减少了汽车厂的生产上序.     

Recent Development on Theory and Application of Variable Gauge Rolling,a Review

Variable gauge rolling （VGR） is a new technology for producing the materials which have the advantage of lightweight due to optimized thickness according to load distribution. The new progresses in the theoretical research and application of VGR are reviewed in this paper. Two basic equations, VGR-f and VGR-s, were deduced. The former is a new differential equation of force equilibrium, and the latter is a new form of formula for the law of mass conservation. Both of them provide a new base for the development of VGR analysis. As the examples of VGR＇s application, tailor rolled blank （TRB） and longitudinal profile （LP） plate are introduced. Now TRBs are only produced in Germany and China, and have been used in the automotive manufacturing to play an important role in lightweight design. LP plates have been used in shipbuilding and bridge construction, and promised a bright prospect in reducing construction weight. In addition, new technologies and applications of VGR emerge constantly. Tailor welded strips and tailor rolled strips with variable thickness across the width can be used for progressive die and roll forming. The 3D profiled blank can be obtained by two-step rolling process. Tailor tubes witli the variable wail thickness are an efficient way to reduce the weight. The blank with tailored thickness and mechanical property is also under development. Above products based on the tailored ideas provide a new materials-warehouse for the designers to select so as to meet the needs of weight reducing and material saving.     

Superplastically Formed Friction Stir Welded Tailored Aluminum and Titanium Blanks for Aerospace Applications

The purpose of this study was to develop a specialized friction stir welding process for superplastic grade aluminum alloy 5083-SP and titanium alloy 6Al-4V, in thickness of 1.5-4 mm, such that the butt welded nugget would have equal superplastic forming (SPF) characteristics as the parent sheet material. The concept of using tailored blanks for the SPF process is proposed which will allow the joining of multiple pieces to fabricate much larger monolithic components than has been possible in the past. Another benefit of using tailored blanks for SPF applications was found to be a more closely matched blank shape relative to the plan size of the SPF forming die. However, shape of the tailored blanks is critical in SPF of a component. An example of this might be the case where a polygon-shaped blank might work in order to reduce the amount of material used, but a rectangular blank is currently used because a tailor made blank with superplastic joints was not found to be technologically feasible. Upon development of a suitable FSW process for each material, the technology was applied to fabricate full scale test components representing a generic jet engine nacelle Lipskin.     

A review on tailored blanks—Production,applications and evaluation

Tailored Blanks is the collective for semi-finished sheet products which are characterised by a local variation of the sheet thickness, sheet material, coating or material properties. With these adaptions the tailored blanks are optimised for a subsequent forming process or the final application. In principle four different approaches can be distinguished to realise tailored blanks: joining materials with different grade, thickness or coating by a welding process (tailor welded blanks), locally reinforcing the blank by adding a second blank (Patchwork blanks), creating a continuous variation of the sheet thickness via a rolling process (tailor rolled blanks) and adapting the material properties by a local heat treatment (tailor heat treated blanks). The major advantage of products made from tailored blanks in comparison to conventional products is a weight reduction. This paper covers the state of the art in scientific research concerning tailored blanks. The review presents the potentials of the technology and chances for further scientific investigations.     

Brazing zirconium alloys with an amorphous rapidly quenched strip brazing alloy

Application of aluminum alloy, which is a typical lightweight material, has been expected to achieve energy saving and prevention of pollution in many kinds of transportation vehicles. While the structure made of whole aluminum alloy, however, is lightweight, it still has problems, such as low mechanical strength and high cost. Hence, a hybrid or joining structure made of aluminum alloy and steel seems to be reasonable because of its light weight and higher strength.

To make a hybrid structure for transportation vehicles, we examined welding by friction stirring between aluminum alloy and low-carbon steel, which could be welded without melted weld materials. As a result, welding between aluminum alloy and low-carbon steel that had a thin intermetallic compound at the weld interface was obtained.

In recent automobile manufacturing, zinc-coated steel has been used for structural parts in general. On welding between zinc-coated steel and other materials such as aluminum alloy, existence of a Zn layer between aluminum and steel has to be taken into account to get a high-quality joint between the materials.

In this study, spot joining between aluminum alloy and several kinds of zinc-coated steels by friction stirring was carried out, and the effect of the coated layer both on the weld strength and weld interface microstructure was investigated. As a result, the joint between aluminum alloy and zinc-coated steel was stronger than that between aluminum alloy and non-coated steel, when the coated layer was removed at the weld interface by plastic flow of aluminum alloy.     

On the growth of intermetallic phases by heat treatment of friction stir welded aluminum steel joints

Multi-material components made from aluminum and steel sheet metal are an innovative approach for weight reduction in automotive applications. However, lightweight components made from aluminum and steel require suitable joining technologies. A promising solid-state welding technology for producing dissimilar steel aluminum joints is Friction Stir Welding, which minimizes the formation of Fe-Al intermetallic phases due to process temperatures lower than the melting temperatures of the base material. The results obtained show a comparison of steel aluminum joints made by FSW using DC04 mild steel with the strain hardened aluminum alloy AA5754-H22 on the one hand and the precipitation hardened aluminum alloy AA6082-T6 on the other hand. The difference between achieved maximum tensile strengths of the joints in relation to those from both base materials is investigated. Due to the stirring and heat input of the welding process, the temper condition of the precipitation hardened aluminum alloy is changed. To improve the mechanical properties of the welded joints, post weld heat treatments are performed. The post weld heat treatments of the produced multi-material specimens from AA6082-T6 aluminum alloy and mild steel at various heat treatment conditions show substantial growth of intermetallic phase layer, which is characterized in detail within the present work. Tensile tests show a degradation of the mechanical properties resulting in a decreased tensile strength and insufficient connection of both materials. Investigations using a scanning electron microscope (SEM) show a distinct increase of the thickness of intermetallic phases in the transition between aluminum and steel.     

一种铝合金翼开启厢式货车车厢两翼的优化设计

铝合金具有比重小、冲压塑性大、耐腐蚀、回收价值高等优势,有些牌号的铝合金在使用性能上已接近或者超越传统钢铁材料。用铝合金材料替代钢材进行翼开启厢式车开发研究有重要意义。对现有Q235材料车厢两翼结构和铝合金材料两翼相同部分进行有限元分析,对铝合金材料车厢两翼结构进行相应拓扑优化,得近似桥梁桁架的两翼改进结构。分析结果表明:铝合金材料车厢两翼骨架改进结构满足强度等设计要求,翼开启厢式车车厢两翼轻量295%,优化设计取得良好效果。     

汽车轻量化用铝合金板冲压成形性研究

在实现汽车轻量化的进程中,越来越多的铝合金应用于汽车工业中。在总结汽车用铝合金板特点及其力学性能的基础上,提出了铝合金板在冲压成形过程中的开裂、回弹和表面损伤等问题及相应解决措施,并得出了材料特性、润滑条件和压边力是影响铝合金板冲压成形性能的主要影响因素。     

铝合金陶瓷涂层的研究进展

铝合金具有密度小、质量轻、成形加工性好等诸多特点,逐渐成为汽车、摩托车轻量化和节约能源的理想材料,但铝合金硬度低、耐磨性差的缺点,制约了它在一些重要零部件上的应用.铝合金表面陶瓷化技术使其与陶瓷材料互相复合,取长补短,使得铝合金表面性能得到了一定程度的提高.综述了铝合金陶瓷涂层技术的研究现状,介绍了制备涂层的主要工艺方法,技术特点,主要包括热喷涂法、激光熔覆、阳极氧化、溶胶-凝胶等,并展望了铝合金陶瓷涂层技术的发展趋势.     

Tensile and Fatigue Behavior of Friction-Stir Welded Tailor-Welded Blank of Aluminum Alloy 5754

Friction stir welding is becoming increasingly desirable in many applications, including tailor-welded blanks in which two sheets of different thicknesses are joined together to form blanks that can be subsequently stamped into a final product shape. In this article, we have studied the static tensile and tension-tension fatigue behavior of friction stir welded joint in a tailor-welded blank of aluminum alloy 5754. It was observed that the yield and tensile strengths of friction stir welded specimens with weld located 90° to the tensile direction are close to the base material values, but its elongation is nearly half the elongation for the base material. The friction stir welded joints had relatively high-fatigue strength, and was even superior to that of the base aluminum alloy in the high-cycle region. Pre-straining caused by press forming lowered the elongation to failure, but improved the fatigue performance.