| 摘要 |
PURPOSE:To prevent the generation of a pockmark flaw and a pit flaw on an inner surface, caused by bitten scale by perfectly removing secondary scale on the inner surface of a pierced shell in a plug for rolling a seamless steel tube. CONSTITUTION:The secondary scale in a shell 9 is mechanically removed by making a water-jet rotor 2 mounted on the tip part of a plug 8 rotate at a high speed, and making a descaling brush 7 which is coaxial with the water-jet rotor 2 rotate by high-pressure water sent through a through path 13 in a mandrel bar 1. Then, a pockmark flaw and a pit flaw on an inner surface, caused by the secondary scale, are prevented and a yield is improved by perfectly removing the secondary scale on the inner surface of the shell. |
