Linear Friction Stir Welding of Medium Carbon Steel at Low Temperature

Linear Friction Welding (LFW) is a solid-state joining process in which a joint is obtained through the relative motion of two components under a high contact load. The most important factor of this conventional method is to obtain a fresh surface at the interface by expelling the weld interface as flash. In this study, medium carbon steel was welded by LFW at a low frequency, low amplitude and high applied pressure. As a result of the temperature measurements and microstructure observations, the maximum temperature of the weld plane was confirmed to be below the A(1) transformation temperature, and martensitic transformation was suppressed at the weld interface. The key concept of this method is applying a large strain deformation to the interfaces to recrystallize at a lower temperature which is different from the conventional LFW.