| 摘要 |
PURPOSE: A method for measuring length of slab before charging the slab into reheating furnace in hot rolling process is provided to measure length of the slab on the roller table using oscillation control function and photo sensors without returning of the slab loaded on hot rolling roller table to a table in front of the furnace at the charging side of the reheating furnace. CONSTITUTION: In a method for measuring length of slab on the A1 roller table(120) on which a plurality of length measuring photo sensors(312-315) are installed with being spaced apart from each other in a certain distance among roller tables(110,120,130) for transferring slab before charging the slab into a hot rolling reheating furnace, the method for measuring length of slab before charging the slab into the reheating furnace in the hot rolling process comprises a step of reverse driving the A1 roller table by sensing the slab using fourth photo sensor(314) installed at a central part of the A1 roller table if the slab is loaded on the A1 roller table; a step of stopping driving of the A1 roller table by sensing an end part of one side of the slab moved backward by reverse driving of the A1 roller table using second photo sensor(312) or third photo sensor(313); a step of starting measuring length of the slab by forward driving the A1 roller table so that PLG count addition is started from a time point when the second or third photo sensor is in the off state if the A1 roller table is stopped; and a step of converting length of the slab from return distances (XA,XB,XC) and distances (S3,S4) between the photo sensors by stopping driving of the A1 roller table and PLG count addition at a time when the fifth photo sensor(315) senses an end part of the other side of the slab if the slab is moved forward by forward driving of the A1 roller table.
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