Friction stir welding （FSW）technology is a solid-phase connection technology.

It can seal and connect water chambers with the outer cover, which are  formed by different processes .This method does not require solder or flux, and can ensure that the entire weld joint obtains a uniform and consistent welding depth and a dense weld structure in the forged state. It has good sealing performance, high weld strength, and is close to the base material.