| 摘要 |
PURPOSE:To process easily a groove of roll die and to increase a capacity of roll die in cold elongating a metallic pipe by forming the cross-sectional shape of a working zone of roll groove into a specific shape, in a roll die of a cold Pilger mill. CONSTITUTION:In manufacturing a finished pipe 5c through a cold elongation of a metallic blank pipe 5a by using rolls 2, 2 provided with grooves 1 and a mandrel 4, the pipe 5a is elongated at a working zone 1a of the groove 1 and finished at a sizing zone 1b, and is delivered by a prescribed quantity while rotating around the pipe axis by 30 deg. or 60 deg. at the time when both rolls 2, 2 rotate mutually in opposite directions and return to the large diametral side of the mandrel 4 to make their play parts 1c face each other, and the pipe 5c is formed by repeating these operations. At that time, when the distance Bi between the center of the 1st circular arc 11 of the working zone 1a of the roll groove 1 and the center of the 2nd circular arc 12, and the radius Ri of the 2nd circular arc 12 are respectively made to the values expressed by equations ( I ), (II), the manufacturing capacity of the finished pipe 5c is increased. |
