Who invented friction stir welding?

Friction Stir Welding (FSW) was invented by Wayne Thomas of the Welding Institute in 1991. The TWI is a British research and technology organization specializing in welding.
In 1995, a second patent was filed to extend the application to the tool level.
In early 2015, the Welding Institute patent fell into the public domain. This allowed FSW to be more widely exploited. Today, this technology finds high-quality applications all over the world.
As an industrial member of TWI, Stirweld participates, with their teams, in several collaborative projects involving FSW expertise.