TUBE WITH SPIRAL GROOVED INNER SURFACE, MANUFACTURING METHOD THEREFOR, AND HEAT EXCHANGER

摘要

PROBLEM TO BE SOLVED: To provide a tube with a spiral grooved inner surface having high heat transfer properties and a manufacturing method therefor. ! SOLUTION: A tube with a spiral grooved inner surface is manufactured by directly applying twisting to an aluminum alloy extruded stock tube with a plurality of straight grooves along a length direction formed on an inner surface at a distance in a circumferential direction, and includes: a plurality of large spiral grooves along the length direction at a twist angle of 15° or more; and at least one small groove formed on a bottom of the large grooves. A fin is constituted by the large grooves among the large grooves, a depth of the small groove is equal to or greater than 30 μm and equal to or less than 25% of a thickness of the bottom of the large grooves, and a mean crystal grain size is equal to or less than 120 μm in a crystal grain structure. ! COPYRIGHT: (C)2014,JPO&INPIT