Abstract Multi-material design offers cost-efficient lightweight solutions for automotive body-in-white production. It can be realized by joining ultra-high strength steels with aluminum alloys, using adhesive bonding, combined with another commonly used joining process. For these applications, processes like riveting, clinching, resistance spot welding have been pushed to their technological limits and a further technological development is needed. The present research describes a new joining technology based on resistance welding process for joining aluminum-silicon coated hot stamped ultra-high strength steel with aluminum. The technology consists of a two-stage projection welding process with an additional insert element. Its implementation allows joining aluminum and steel sheets using extremely short welding time with high energy concentration in combination with adhesive bonding. Due to low heat input in the welding process, the adhesive around the insert element is damaged significantly less, compared to classic resistance spot welding. Depending on insert element size and orientation, short flanges can be joined, offering potential for further weight reduction of the car body. The elements are easily applicable under different production constraints. One of possible applications of the investigated joining process is welding a thin outer aluminum sheet on a B-pillar. Welds were made using insert elements – cylinders of Cu- and Fe-based wires with diameter of 1.6 mm and length of 10 mm employing a medium frequency direct current resistance welding machine. Both tested materials can be successfully used and the weld current ranges are sufficient for industrial application with and without the use of adhesive. Mechanical properties of joints, evaluated using tensile-shear tests, are comparable with those of the existing mechanical joining methods used in automobile manufacture.

中文翻译：

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使用新型插入元件通过粘合剂粘合和凸焊的混合工艺将铝与钢连接起来

摘要 多材料设计为汽车白车身生产提供了经济高效的轻量化解决方案。它可以通过将超高强度钢与铝合金连接起来，使用粘合剂结合，结合另一种常用的连接工艺来实现。对于这些应用，铆接、铆接、电阻点焊等工艺已达到其技术极限，需要进一步的技术发展。本研究描述了一种基于电阻焊工艺的新型连接技术，用于连接铝硅涂层热冲压超高强度钢与铝。该技术包括带有附加插入元件的两阶段凸焊工艺。它的实施允许使用极短的焊接时间和高能量集中结合粘合剂粘合来连接铝板和钢板。由于焊接过程中的低热量输入，与传统电阻点焊相比，插入元件周围的粘合剂受到的损坏要少得多。根据插入元件的尺寸和方向，可以连接短法兰，为进一步减轻车身重量提供潜力。这些元素很容易适用于不同的生产限制条件。所研究的连接工艺的可能应用之一是在 B 柱上焊接薄外铝板。使用插入元件进行焊接——直径为 1.6 毫米、长度为 10 毫米的铜基和铁基焊丝圆柱体，采用中频直流电阻焊机。两种测试材料都可以成功使用，焊接电流范围足以满足工业应用，无论是否使用粘合剂。使用拉伸剪切试验评估的接头机械性能与汽车制造中使用的现有机械连接方法的机械性能相当。