Mechanical property effects of symmetrical hour glass shapes formed during double-sided TIG keyhole arc welding of AISI1040 joints

Abstract

In this study, AISI1040 steel sheets of 10 mm thickness were welded in butt position without pretreatment by double-sided TIG keyhole arc welding process. Weld joints were produced by using three different welding currents (410, 430 and 450 A), electrode diameter (empty set: 3.2 mm), a constant shielding gas flow rate (81 x min(-1)) and welding speed (0.01 m x min(-1)). Microstructural changes occurred in the fusion line of the weld samples were examined by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and microhardness analysis. V-notch Charpy and tensile tests were carried out to determine the bond strength of the weld samples. In addition, fracture types of the tensile test samples were determined by the help of fractographic examinations using SEM and EDS. Consequently, the weld samples produced by double-sided TIG keyhole technique are approximately symmetrical and hour glass shaped. Also, it was found that penetration depth increased with current density.