铝/钢异种材料电阻点焊研究进展

Research Progress of Resistance Spot Welding of Aluminum/Steel Dissimilar Metals

铝/钢电阻点焊技术是促进铝/钢混合轻量化技术在汽车产业应用的关键技术之一,但铝合金与钢材的传热性、导电性和热膨胀性的差异较大,且电阻点焊接头界面会生成脆性的金属间化合物(IMC)层,因此难以形成良好焊接。近年来,改进设计后的电极提高了铝/钢电阻点焊的焊接性能,并且由于焊接工艺的优化,实现了铝/钢电阻点焊的高质量连接。学者们探究了铝/钢接头界面IMC的生长机理和接头的断裂失效机理,也研究了IMC厚度、熔核直径、钢涂层类型、焊接工况和腐蚀对点焊接头性能的影响,并通过优化焊接参数、引入垫片或中间层及复合焊接等方式来提高焊接质量,以最终指导铝/钢电阻点焊焊接工艺设计并推动其工程应用。本文主要从IMC的生长机理、接头断裂失效行为、焊接质量的影响因素、工艺优化方法和焊接仿真分析等方面综述铝/钢异种材料电阻点焊的研究进展。

A luminum/steel resistance spot welding(RSW)is an important technology to promote the application of lightweight materials in automotive industries.However,aluminum alloys and steels are significantly different with each other in thermal conductivity,electrical conductivity and thermal expansion.Moreover,a brittle layer of Al-Fe intermetallic compound(IMC)is prone to form at the Al/steel faying interface.These disadvantages make it quite challenging to obtain sound welding joints between aluminum alloys and steels.In recent years,the improved design of electrodes have enhanced the welding performance of Al/steel RSW,which combined with the process optimization leads to achieving acceptable quality of Al/steel RSW.Researchers revealed the growth mechanism of IMC and the fracture failure mechanism of aluminum/steel RSW joints.The influence of IMC thickness,weld nugget diameter,the steel coating types,welding production conditions and corrosion on the quality of aluminum/steel RSW joints were studied in detail.Various methods have also been proposed to improve the welding quality,such as optimizing the welding parameters,employing the cover plate or interlayer and hybrid welding,which ultimately guide the design of welding process and promote the application of aluminum/steel RSW in automotive industries.This contribution gives a review of the global research in Al/steel dissimilar RSW.It mainly focuses on the micro-level causal occurrences of IMC growth,fracture behavior of welded joints,factors influencing welding quality,process optimization methods,and simulation analysis of welding.