HEAT EXCHANGER TUBE WITH GROOVED INNER SURFACE, TUBE EXPANSION METHOD THEREFOR, AND DEVICE FOR MANUFACTURE THEREOF

摘要

A heat exchanger tube with a grooved inner surface (1), wherein a plurality of protruding fins (2) are formed on the inner surface of a metallic tube, and an inclined surface (2C) which approaches the inner surface of the metallic tube in a direction of one end of the metallic tube is formed at the peak section of the fins (2). The angle formed between the inclined surface (2C) and a normal line from the metallic tube inner surface is between 30 to 70 DEG , and the angles between the two side wall surfaces (2A, 2B) of the fin and a normal line from the metallic tube inner surface are both between 5 to 15 DEG .