On the Process Variables and Weld Quality of a Linear Friction Welded Dissimilar Joint between S31042 and S34700 Austenitic Steels

In this study, the dissimilar S31042 and S34700 austenitic stainless steels joints are welded with linear friction welding (LFW). The history of shear stress at the interface and axial shortening during LFW, the microstructure evolution and mechanical properties of the joint are studied. Results show that axial shortening develops during the equilibrium and deceleration phases. The shear stress reaches a maximum during deceleration as a metallurgical bond forms in sections of the interface. The weld center zone is a narrow layer with a thickness of about 380 µm, where there are fine equiaxed grains with a strong {112}<110> texture. Elongated grains are present in the thermo-mechanically affected zone due to the shear stress. The average tensile strength and elongation of the joints are measured to be 577 MPa and 33.3%, respectively. All tensile test samples fail at the base material of S34700, as the tensile strength of the joint is equal to or better than that of the base S34700.