Comparative analysis of microstructure and quality of gas metal arc welded and shielded metal arc welded joints
Keywords:grain size, GMAW, materials testing, microstructure, SMAW, welding
In this work a comparative study of two metal arc welding methods Gas Metal Arc Welding (GMAW or MIG) and Shielded Metal Arc Welding (SMAW) were performed as well as quality and microstructure of welds were compared. The first one is the welding type with consumable electrode and gas shielding, and the second one is the welding method with consumable, flux coated electrode especially used for repairing. To ensure the satisfactory performance of a welded structure, the quality of the welds was determined by adequate testing procedures. The tests were performed on specimens manufactured according to Lithuanian Standard Board requirements, specifically LST EN 895:1998. Test pieces made of structural steel S235JR (LST EN 10027-1) were subjected to welding. Obtained microstructures revealed differences between two welding methods used for experiments, while the evaluation of grain size confirmed the former results of tensile strength tests.