Why is friction stir welding preferred over more conventional fusion types of welding in certain applications?
Ding: Well, the number one reason is the fact that you aren’t melting the material, so you get much higher weld mechanical properties from the weld joint as compared to the fusion weld processes. That’s the primary reason. Another reason is that it’s a highly automated process and very repeatable. If there were ever a weld process where you just push the button and let her go, this is it. There are four process variables – the pin rotational speed (RPM), travel rate, the force that the shoulder is pushing into the part, and the position of the shoulder below the surface of the weld piece. They are all highly computer controlled. Once you develop a parameter window and find the optimal parameters, you will perform the same weld over and over. The reliability and repeatability of manufacturing processes is very important when fabricating man-rated space hardware. NTB: I assume you don’t have to heat treat it afterwards? Ding: No. In some instances you might want to heat treat the whole p
