| 摘要 |
PURPOSE:To prevent the occurrence of uneven hardening based on the reflux of cooling water, at the time of anealing a steel pipe, by forming the cooling water flow which is parallel to the axis in a water tank and encloses the inside and outside surfaces of the steel pipe thereby cooling the steel pipe. CONSTITUTION:A heated steel pipe W to be hardened is disposed horizontally in a water tank 1, and cooling water is sprayed parallel to the axis of the steel pipe W from the nozzles 3, 8 provided to the side wall 1W on one side of the water tank and is passes the inside ad outside surfaces of the steel pipe W along its axial line to simultaneously cool and harden the steel pipe W from the inside ad outside. At this time, the diameter of the nozzle 8 for cooling the outside circumferential surface of te steel pipe W is made larger than the outside diameter of the steel pipe W. If the steel pipe W is of a small diameter, the nozzle 3 for cooling the inside surface may be omitted. In addition, it is equally well to penetrate the nozzle 8 per se through the water tank to form the nozzle by dividing to three nozzles 8a-8c. With this method, the hampering of the cooling water by the reflux of the cooling water of the other nozzle and the degrading of cooling effect do not occur. |
