| 摘要 |
PURPOSE: A rough-milling apparatus and a method thereof are provided to appropriately control a bar speed at a third milling roll depending on the bar speed at a fourth milling roll when a bar passing through a rough-milling roll proceeds to the fourth milling roll and is rolled, thereby preventing accidents like loop and necking. CONSTITUTION: A rough-milling apparatus comprises first to fourth milling rolls, a speed measuring unit and a control unit. A slab passes through the first to the fourth milling rolls in consecutive order and is rough-rolled to be a bar. The speed measuring unit measures the speed of the bar passing through the third and fourth milling rolls. The control unit controls the speed of the bar at the third and fourth milling roll or a draft percentage of the fourth milling roll depending on the speed measured in the speed measuring unit. [Reference numerals] (AA) Start rough-milling; (BB) Pass through R1-R3; (CC) Is it strong steel with high temperature strength?; (DD) Reduce the speed to enter R4; (EE) Monitor R4 speed; (FF) Is the impact drop of R4 over 10%?; (GG) Control R3 speed; (HH) Control the ratio of entering R4; (II) Control normal AMTC (apply the control for the distance 15m away from the fore-end) |
