TUBE FOR HEAT EXCHANGERS AND METHOD OF MANUFACTURING SAME

摘要

A tube for heat exchangers, in which roll forming is used to form a bead compartmenting medium flow passages in a tube and a thickness (B) of the bead base is made larger than that of a stock plate for the tube. The roll forming comprises a first step of bending and forming the plate successively in a concave form to provide a planned bead portion as an intermediate formed bead portion, a second step of drawing the planned bead portion laterally, and a third step of compressing the planned bead portion after the second step in a bead heightwise direction. A width (w') of recesses of the planned bead portion (21a) in the first step is made larger than a width (w) of recesses of beads (21) after forming, and a height (h') of the planned bead portion (21b) after the second step is made larger than a height (h) of the bead (21) after forming. Accordingly, methods of manufacturing a heat exchanger tube, in which bases of beads are enhanced in pressure resisting property, and a heat exchanger tube, in which unevenness of the plate can be reduced when beads are formed, are obtained.