Hearth brushing the rolls of steel sheet manufacturing methods and hearth roll brushing method

摘要

PURPOSE: A method is provided which manufactures strip for brushing hearth rolls to remove foreign materials adhered to the surface of the hearth rolls of high temperature annealing furnace used when manufacturing grain-oriented magnetic strip, and a method for brushing the hearth rolls using the strip for brushing the hearth rolls is provided. CONSTITUTION: The manufacturing method of strip for brushing hearth rolls comprises the process of nitriding a cold rolled strip for manufacturing grain-oriented magnetic strip comprising 0.04 to 0.07 wt.% of C, 2.5 to 4.0 wt.% of Si, 0.5 to 0.25 wt.% of Mn, 0.03 wt.% or less of P, 0.02 wt.% or less of S, 0.1 wt.% or less of Al, 0.01 wt.% or less of N and a balance of Fe and other inevitably contained impurities at a dew-point temperature of 53 to 70 deg.C and nitriding temperature of 800 to 900 deg.C for 1 to 5 minutes as injecting ammonia gas into an atmosphere during high temperature annealing of the grain-oriented magnetic strip in a flow rate of 2.00 to 5.5 Nm¬3/hr. In a method for brushing the surface of the hearth rolls(6) using frictional force between the strip for brushing the hearth rolls and the hearth rolls by connecting a strip(7) for brushing hearth rolls to grain-oriented magnetic strip annealed at high temperature in an annealing furnace including hearth rolls, thereby moving the strip for brushing the hearth rolls in the state that the strip for brushing the hearth rolls is contacted with the surface of the hearth rolls by rotation of the hearth rolls, the brushing method of the hearth rolls comprises the process of brushing the surface of the hearth rolls for 5 to 10 minutes by using the strip for brushing the hearth rolls and rotating the hearth rolls to a rotation speed of 10 to 20 m/min in a rotation direction opposite to a proceeding direction of the strip.