| 摘要 |
PURPOSE:To make the water level in a water tank for hardening easily changeable in a short time in the stage of immersing the heated steel pipe in the cooling water in the water tank for hardening while rotating said pipe by changing the water level in the water tank according to the vertical movement of a water storage tank communicating with said tank. CONSTITUTION:A steel pipe 1 heated to a prescribed temp. is carried on revolving rolls 9 in a water tank 1 for hardening by a suitable conveyor; at the same time, the pipe 1 is rotated by the revolution of the rolls 9. The water level of the cooling water in the tank 11 is low in this stage and the cooling water is not in contact with the pipe 1. When a water storage tank 2 is moved upward by the operation of a cylinder device 12 in this stage up to the position of a broken line, the water level in the tank 11 rises up to a broken line level 20 so that the pipe 1 is thoroughly immersed in the water. High pressure cooling water is ejected from an internal cooling nozzle at the same instant when the water level rises, thereby hardening the inside and outside surfaces of the pipe. The tank 2 is lowered upon completion of the hardening to lower the water level in the tank 11, thus exposing the pipe 1 from the water surface. The hardened pipe 1 is then ejected to the outside of the tank 11. |
