Effect of rotational speed on the microstructure and mechanical properties of rotary friction welded AISI 1018/AISI 1020 asymmetrical joints

Asymmetrical joints (joining of the plate with rod) were joined using traditional fusion welding processes. However, the usage of unsuitable filler wire tends to lower weld penetration over the material surface, which also results in the attainment of hot or solidification cracks over the weld surface. To overcome these issues, solid-state welding processes are preferable. This study investigates the rotary friction welding (RFW) of AISI 1018 low carbon steel plate with AISI 1020 low carbon steel rod of asymmetrical joints. The friction welding process parameters such as rotational speed were taken as variable, and other parameters like friction pressure, forging pressure, friction time, and forging time were kept constant in this investigation. The impact of rotational speed on macrostructure, microstructure, and mechanical characteristics of joints such as microhardness, tensile strength, and fractography studies was analyzed. The fractured surface of the tensile specimen was examined through a scanning electron microscope (SEM). The maximum tensile strength of the joint about 452 MPa was observed. Maximum hardness at the weld interface was perceived at about 252Hv. Increasing rotational speed tends to increase the strength of the asymmetrical steel joints in rotary friction welding.