MANUFACTURE OF TUBE WITH GROOVE ON INTERNAL SIDE, FOR HEAT-EXCHANGER DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a manufacturing method of an internally grooved metallic tube having a lateral welded seam whose welding is of a high quality where an additional guide for the edges of a sheet metal is eliminated. SOLUTION: A smooth metallic tape 2 is drawn out from a ring-shaped bundle and multiple grooves are made by a rolling mill in a way that they are extending in parallel to each other and running at an angle of 15 deg. to 45 deg. with respect to the longitudinal direction of the metallic sheet, continuously formed into a tube leaving a slit in a longitudinal direction, and the slit is welded. At least two groups of grooves 10 extending in parallel to each other are rolled on the surface of the metallic sheet so that the grooves are extending forming a herringbone pattern.