Structure and properties of KTIG-MIG coupling welding butt joint

To investigate the potential of KTIG-MIG coupling welding in improving welding efficiency and quality for medium-thickness Q235B low-carbon steel plates, this study specifically analyzes the microstructural characteristics of three distinct regions in butt joints-the base metal(BM), heat-affected zone(HAZ), and weld metal zone(WMZ)-while simultaneously conducting comprehensive mechanical property testing on the welded joints. The test results of mechanical properties are combined with the data of microstructure analysis. The relationship between mechanical properties and microstructure of the WMZ of the butt joint is found. The results show that the microstructure of weld zone does not change significantly with the increase of heat input, but the grain structure of fusion zone and heat affected zone increases gradually. The tensile properties of welded joints are better than those of base materials under different heat input conditions.