MANUFACTURING METHOD FOR TUBULAR BODY, AND ROLLING MACHINE

摘要

PROBLEM TO BE SOLVED: To inexpensively and consistently provide an excellent brazed condition of joining parts of obtained heat transfer tubes. SOLUTION: A long plate 1 is fed into a space with outer circumferential surfaces of first and second rollers 12a and 13a close to and facing each other, and both ends of this plate in the width direction are folded at right angles to form each joined portion 2 on both ends. The portion to be folded at right angles at both ends is pressed between a small diameter cylindrical part 29 provided on an outer circumferential surface of the first roller 12a and a large diameter cylindrical part 33 provided on an outer circumferential surface of the second roller 13a. The radius of curvature of the section of an outer surface of a base end of each joined portion 2 in the case of being cut by a plane orthogonal to the longitudinal direction of the plate 1 can be reduced thereby.