HEAT TRANSFER ELEMENT TUBE AND METHOD OF MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a heat transfer element tube for maintaining adhesion between a heat transfer tube and heat sinks while reducing occurrence of corrosion in the heat transfer tube.SOLUTION: An aluminum heat transfer element tube is connectable to a plurality of heat sinks disposed side by side and in parallel at predetermined intervals by being inserted into insertion holes formed in the heat sinks, followed by tube expansion. The heat transfer element tube has a circular outline in cross section and has a large inner diameter part and a small inner diameter part having different inner diameters which are alternately disposed along a circumferential direction of the heat transfer tube. The large inner diameter part has a Zn diffusion layer on an outer peripheral surface thereof. The small inner diameter part has no Zn diffusion layer.