Abstract: A two-piece wheel is formed by joining a center part to a rim part by a friction stir welding. The weld joints are prepared so that at least a portion of a first circumferential weld joint is not parallel to at least a portion of a second circumferential weld joint. Thus, a cast alloy center part may be securely and efficiently attached to a wrought alloy rim part.

Abstract: A process for making a fluid-tight connection between a tube and a plate-shaped member. The process entails inserting one end of a tube into a correspondingly-sized hole in a plate-shaped member so that the tube end contacts the plate-shaped member and extends beyond a surface of the plate-shaped member. A mandrel is then inserted and pressed into the tube end while heating the mandrel to a temperature sufficient to soften and deform the tube end and increase contact between the tube end and the plate-shaped member, such that the tube is secured to the plate-shaped member and a fluid-tight seal is formed therebetween.

Abstract: The present invention relates to a method of friction welding for joining of members and more particularly to so-called friction stir welding based on a relative rubbing movement between a probe of harder material and members to be joined. The present invention also is directed to an improved tool to be applied in the friction welding process.