Effect of inertia friction welding speed on microstructure and mechanical properties of 2205/316L stainless steel joints

In this paper, inertia friction welding (IFW) is used to enable a high-quality and efficient joint between 2205 duplex stainless steel and 316 L stainless steel. Specifically, stainless steel bars (2205/316 L) with a diameter of 35 mm and length of 120 mm are used. In addition, the effect of IFW speed on the microstructure and properties of welded joints is assessed using scanning electron microscopy, electron backscattered diffraction, energy dispersive X-ray spectroscopy, microhardness test, and tensile tests. The results indicate that dynamic recrystallization of the microstructure of joints occurs during IFW welding, which causes grain refinement. The diffusion of Ni from the 316 L base metal to the 2205 base metal, as well as the diffusion of Cr from the 2205 base metal to the 316 L base metal, results in a strong metallurgical bond between the two materials. In addition, the microhardness of the welding area exceeds that of the base metal (the closer to the weld zone, the greater the microhardness value). The tensile strength of the joints initially increases with increasing IFW speed, but then it starts decreasing beyond a certain point. The optimal welding parameters for achieving high-quality joints between 2205 duplex stainless steel and 316 L stainless steel are as follows: axial pressure = 5 MPa, rotational inertia = 4.17 kg.m(2), and IFW speed = 2700 r/min.