To provide a manufacturing method for a tapered steel tube, which enables optimal tapering work by adjusting the output of a heating device so that the temperature of a steel tube becomes an optimal working temperature when the steel tube reaches a working roll.
Temperature detecting means 16, 17 are set at least in the outlet side of a heating device 12 and immediately before a working roll device 1, and the temperature falling rate of a steel tube P from the heating device 12 to a working position is actually measured. Temperature falling constants are selected according to working conditions such as a drawing rate, and the drawing is conducted while adjusting the output of the heating device 12 so that the measured temperature falling rate agrees with the calculated one. The temperature falling constants are preferably set so that the constants change stepwise in the longitudinal direction of the steel tube P.
COPYRIGHT: (C)2006,JPO&NCIPI
Manabu Ueda
Hirotoshi Hishida
| JP2002292433A | ||||
| JP57199517A |
Fumio Yamamoto