Tube for heat exchangers and method of manufacturing same

Abstract

A tube for a heat exchanger which is formed to have beads for dividing passages for a medium in the tube by roll forming, wherein base portions of the beads are formed to have a thickness (B) greater than a thickness of a plate material for the tube. The roll forming has a first step of sequentially bending the plate to have a depressed shape to form portions-to-be-bead which are to be intermediate forms of the beads, a second step of performing a width drawing of the portions-to-be-bead and a third step of compressing the portions-to-be-bead, after the second step, in a direction of the height of the beads, wherein a width (w′) of the depressions of the portions-to-be-bead ( ) in the first step is larger than a width (w) of depressions of beads ( ) after forming, and a height (h′) of portions-to-be-bead ( ) after the second step is determined to be higher than a height (h) of the beads ( ) after forming. Thus, the tube for a heat exchanger having a pressure resistance of the base portions of the beads improved and a method for producing the tube for a heat exchanger which can decrease an uneven thickness of the plate when the beads are formed are obtained.