Investigating the effect of pin and shoulder rotational speed on the mechanical properties of friction stir processed region in Al6061

Friction stir process is one of the process that improve the mechanical and metallurgical properties of metals surface. One of the important parameters in this process which affect mechanical and metallurgical properties is rotational speed of shoulder and pin tool. In this study, unlike the other research a new tool was designed and manufactured in such a way that rotational speed of pin and shoulder is seperatable from each other and each one can adopt different speed. Friction stir process was done with constant rotational speed of shoulder (800 rpm) and different rotational speed of the pin(800, 1000 and 1250 rpm). Maximum temperature and mechanical properties of the samples was investigated. The results showed that the maximum temperature does not increase greatly with increasing the rotational speed of the pin (2% increase with 25% increase in the rotational speed of the pin). Mechanical properties of the samples increased with increasing the rotational speed of the pin. The ultimate stress was increased 18% when the rotational speed of the pin was changed from 800 rpm to 1250 rpm.