| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for suppressing surface indentation flaw in an element tube (an element tube for a seamless steel tube) applied with correction by a straightener after made by hot tube making, and thereafter provided for cold working. <P>SOLUTION: In time of the correction by the straightener, cooling water is sprayed onto the whole faces of rolls constituting the straightener, and a load applied to the straightener rolls is set to be 550 kN or below to perform light rolling reduction of the tube stock. It is effective that a hot straightener applying the correction such as bend removal to the tube stock present in a temperature range of 500-550°C after the hot tube making is used as a means of the light rolling reduction. It is preferable to perform the spray of the cooling water onto the whole roll faces by at least one means of means of angle widening of a tip shape of each cooling nozzle, proper arrangement of the cooling nozzles 5, and increase of a spray water amount of the cooling water. <P>COPYRIGHT: (C)2012,JPO&INPIT |
