Advances in Application of Friction Stir Welding on Steel Joints

Recently, friction stir welding (FSW) has known as an effective tool to modify microstructure and mechanical properties of sheet metals, especially as-cast materials. In the FSW process, the material in the stirring zone undergoes intense plastic deformation which causes a dynamical recrystallization. In this paper, fatigue, strength, hardness and microstructure of FSW- welded joints made of ST12 has been investigated. ST12 steel is now one of the most widely used steels because of its scalability and high strength, which has gained great interest in industrial applications–such as aerospace and automotive–and cases the welding process is required. Enhancement in the hardness, strength, toughness, and elongation of material was found in the welded zone. The case studied in this paper demonstrated that the FSW has excellent strength properties and low heat-affected zone. The FSW provides better performance in the bending fatigue that the S -N curve is on the right side of the TIG-welded piece, strain of joint increased by 47% compared to the conventional techniques such as TIG-welding. Vickers hardness number increased in the weld zone up to 57% than the base metal.

کلیدواژه ها:

friction stir welding ، microstructure modification ، hardness ، sheet ST12 ، bending fatigue