How did you get involved with friction stir welding?ĭing: Back in 1995 I was working in the space shuttle main engine (SSME) chief engineer’s office. Although you’re credited with introducing friction stir welding to NASA in 1995, the technology was actually invented in 1991 by a man named Wayne Thomas and his team of researchers at The Welding Institute (TWI) in Great Britain. 300-in thick aluminum, the pin tool rotates approximately 250 to 300 rpm and traverses the weld joint approximately 6 inches per minute. At this time, the rotating pin tool (shoulder and pin) traverses the weld joint allowing the threaded pin inside the weld joint material to “stir” the abutting joint material. After dwelling for a short period, the shoulder’s frictional energy creates enough heat to allow the aluminum to become soft, pliable, and “mushy” (plastic). Essentially, if you’re welding aluminum, you slowly plunge the rotating, protruding pin into the weld joint until the shoulder comes in contact with the surface of the weld piece. 025-in shorter than the thickness of material being welded. The threaded pin diameter is approximately equal to the thickness of material being welded and the pin length is approximately. The pin tool has a larger diameter shoulder (approximately three times material thickness) from which a smaller diameter threaded pin protrudes. The material is heated into a plastic state – a temperature between solidus and liquidus – using a rotating FSW pin tool. Jeff Ding: Friction stir welding is a solid state weld process, meaning you do not melt the material when you weld. What is friction stir welding, and how does it work?
NASA Tech Briefs: Jeff, you are considered to be NASA’s foremost expert in the field of friction stir welding (FSW).
Ding was Marshall Space Flight Center’s Inventor of the Year in 2000, was awarded the Medal for Exceptional Technology Achievement in 2003, and recently received the 2009 Federal laboratory Consortium Award for Excellence in Technology Transfer. He is also credited with inventing two new solid state welding processes called thermal stir welding (TSW) and ultrasonic stir welding (USW). patents for FSW, including one for an automatic retractable pin tool that solves the troublesome “keyhole” problem. Jeff Ding introduced friction stir welding (FSW) to NASA in 1995.
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