中文摘要：

实现铝钢良好连接的关键是有效控制焊接热输入,尽量降低中间层铝铁金属间化合物的厚度,一般认为中间层金属间化合物厚度小于10μm时铝钢接头质量良好。提出旁路耦合电弧熔钎焊方法,通过调节旁路电弧电流的大小来控制焊接热输入。在优化控制系统和工艺参数的基础上采用脉冲旁路耦合电弧焊方法将铝镁合金ER5356堆焊到304不锈钢板上,获得结合良好的焊缝。对焊接接头进行扫描电镜（Scanning electron microscope,SEM）、能量色散光谱仪（Energy dispersive spectrometry,EDS）分析,结果表明：铝与不锈钢焊接接头中间层金属间化合物平均厚度约为8μm,小于10μm的临界厚度;脉冲旁路耦合电弧焊方法能够实现铝钢的连接,是一种新型低成本低热输入电弧焊方法。

英文摘要：

Hhe key of welding aluminum to steel is accurate control of heat input,aiming at reducing the brittle inter-metallic compound（IMC） in the interfacial layer.A novel gas metal arc welding（GMAW） process,referred to as double-electrode GMAW,is developed to make it possible to increase the wire melting current while the base metal current is still controlled at a desired level.To accurately control the heat-input,pulse double-electrode GMAW experiments are carried out to joint aluminum wire ER5356 to 304 steel on the basis of optimizing control system and welding parameters.Analysis on the welding joint by means of scanning electron microscope（SEM） and energy dispersive spectrometry（EDS） shows that the IMC layer is less than 10 μm,which is the generally accepted critical thickness.Pulse Bypass-Electrode GMAW,being one of economic low heat-input arc welding methods,is feasible for welding aluminum to steel.