Patent attributes
The present invention is characterized by including a heat medium pipe insertion process to insert a heat medium pipe into a concave groove; a lid plate insertion process to insert a lid plate into a lid groove; and a joining process to perform friction stirring while a primary joining rotary tool provided with a base side pin and a tip side pin is moved along a butted portion of a side wall of the lid groove and a side face of the lid plate, wherein in the joining process, friction stirring is performed while the tip side pin of the primary rotary tool which is rotating is inserted into the butted portion and an outer circumferential face of the base side pin is in contact with the base member and the lid plate, and plastically fluidized material fluidized by frictional heat is flowed into a void portion formed adjacent to the heat medium pipe.
