The friction coefficient and the galling process in metal to metal parts depend on many variables such as normal load, lubricant, roughness and design of the friction surfaces. Since developing a mathematical model is very difficult for friction pheenomena and the galling process, these tribological events can be explained with studies taking some parameters as constant. In this study, an experimental system was established in order to investigate the friction coefficient versus the normal load with respect to time. Moreover, yield stress and rotational speed for different materials were determined with the Up and Down Technique. In all the experiments, L80 and J55 tubing materials were used.