Investigation of mechanical and microstructural properties of S355 parts joined by laser and gas metal arc welding

Welded manufacturing is a widely used joining method in modern industrial production processes. In this study, the mechanical and microstructural properties of S355 structural steel plates were examined using Metal Active Gas (MAG) welding and laser welding, which are commonly preferred in the welding industry. S355 structural steel is extensively used in various sectors, including automotive, defense, construction, and heavy industry, due to its high strength and excellent weldability. In the experimental study, different parameters were applied for both welding methods, and tensile strength, impact toughness, microhardness, corrosion resistance, and microstructural properties were evaluated. Microstructural and macrostructural analyses of the welded region were performed, and the microstructural changes in the weld seam and heat-affected zone (HAZ) were examined in detail. Additionally, distortion values after welding were measured using laser scanning technology to compare the effects of both methods on dimensional stability. The results showed that laser welding, due to its lower heat input, resulted in less distortion, exhibited higher mechanical performance, and provided a more homogeneous internal structure. On the other hand, the MAG welding method was observed to offer greater penetration depth in thick-section materials. The efficiency of both methods has been increased with the optimization studies carried out within the scope of the study.