| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a water-cooling process for heat treating steel pipes which can prevent temperature unevenness in longitudinal direction of the steel pipes caused by inflow of cooling water, even when water-cooling is performed after induction heating is conducted continuously on steel pipes in coupled state. <P>SOLUTION: In the heat treatment process, the steel pipes are coupled by pressing the anterior tips of following steel pipes onto the posterior tips of preceding steel pipes before induction heating and sequentially and continuously passed through an induction heater to be heated and water-cooled. As soon as the posterior tip of the preceding steel pipe passes through the induction heater, the carrying speed of the preceding steel pipe is increased to separate it a given distance apart from the anterior tip of the following steel pipe. Thereafter, the carrying speed is adjusted to maintain the given distance while passing the steel pipe through a water cooler equipped with a water spray. Preferably, the given distance is≥100 mm, or the cooling water from the water spray is either sprayed down vertically against the steel pipes or sprayed in the opposite direction toward the induction heater side. <P>COPYRIGHT: (C)2003,JPO</p> |
