To provide a manufacturing method for a tube with internal grooves by which local breakage and local wear of a groove forming roll are prevented and the grooves are stably formed.
Grooved rings 1a-1d having the radius of 50.0 mm on the outer peripheral surfaces of which the grooves having the height of 0.2 mm and groove pitch of 0.2 mm are formed in the direction inclined to the axial direction of the ring. Furthermore, tapered parts having the width of 0.6 mm are formed in the both end parts in the axial direction of the ring and the radius R1 in the end parts are 49.88 mm. The groove forming roll 20 is composed of the grooved rings 1a-1d and flat rings 25, 26 whose outer peripheral surface is flat and radius is 49.88 mm. With this groove forming roll 20 and a flat roll whose outer peripheral surface is flat, the grooves are transferred on one side of a metallic plate. Next, the metallic plate is curved taking the grooved surface as the inside and this butted part is welded.
SAEKI CHIKARA
HINAKO NOBUAKI
KOSEKI KIYONORI
