Characteristics of Light Alloy/ Steel Dissimilar Metals Joint by the Longitudinal Electromagnetic Hybrid TIG Welding - Brazing Method--I.Experimental Research

A new longitudinal electromagnetic hybrid TIG welding-brazing method (LE-TIG-B welding) is applied to light alloy / steel dissimilar metals joining experiments. The microstructure and composition analyses of the different brazed joints are examined using OM, SEM, EDS and Vickers microhardness measurement techniques. The elements distribution, microhardness, welding defect and wetting angle are investigated by the comparison of TIG welding-brazing (TIG-B welding) and LE-TIG-B welding. The result shows that 3003 aluminum alloy / Q235 carbon steel, AZ91 magnesium alloy / 304 stainless steel, AZ31 magnesium alloy / Q235 carbon steel can be formed the tight lap joint by LE-TIG-B welding. The longitudinal electromagnetic field can affect the flowability and surface wettability for the filler metal on the interface of light alloy / steel dissimilar metal joints. The tensile strength of the joints attains a maximum value of 198.6 MPa with the magnetic frequency and magnetic intensity set at 20Hz and 0.01T respectively. The additional longitudinal electromagnetic field can be an inverse affect on the process of light alloy / steel dissimilar metals joining, so the welding parameters need be optimized in LE-TIG-B welding.