Hot-band annealing equipment, hot-band annealing method and descaling method for si-containing hot rolled steel sheet

Abstract

Provided is a hot-band annealing equipment provided with a heating zone, a soaking zone and a cooling zone for subjecting a Si-containing hot rolled steel sheet to hot-band annealing, wherein when the Si-containing hot rolled steel sheet is subjected to hot-band annealing with the hot-band annealing equipment provided with a rapid heating device at an upstream side of the heating zone and/or in an inlet side of the heating zone, the hot rolled steel sheet is heated by not lower than 50° C. at a heating rate of not less than 15° C./s by using the rapid heating device to improve a descaling property, whereby descaling can be performed only by pickling without requiring mechanical descaling or heating the steel sheet in the pickling process. Also provided are a hot-band annealing method and a descaling method using the above equipment.

1 - 8 . (canceled) 
     
     
         9 . A hot-band annealing equipment provided with a heating zone, a soaking zone and a cooling zone for subjecting a Si-containing hot rolled steel sheet to hot-band annealing, characterized in that a rapid heating device is disposed at an upper stream side of the heating zone and/or an inlet side of the heating zone. 
     
     
         10 . The hot-band annealing equipment according to  claim 9 , wherein the rapid heating device is an induction heating device or an electric heating device. 
     
     
         11 . A hot-band annealing method for subjecting a Si-containing hot rolled steel sheet to hot-band annealing with the hot-band annealing equipment according to  claim 9 , characterized in that a start temperature for heating the Si-containing hot-rolled steel sheet in the rapid heating device is in a range of room temperature to 700° C. and the Si-containing hot rolled steel sheet is heated by not lower than 50° C. at a heating rate of not less than 15° C./s by using the rapid heating device. 
     
     
         12 . A hot-band annealing method for subjecting a Si-containing hot rolled steel sheet to hot-band annealing with the hot-band annealing equipment according to  claim 10 , characterized in that a start temperature for heating the Si-containing hot-rolled steel sheet in the rapid heating device is in a range of room temperature to 700° C. and the Si-containing hot rolled steel sheet is heated by not lower than 50° C. at a heating rate of not less than 15° C./s by using the rapid heating device. 
     
     
         13 . A descaling method, characterized in that the Si-containing hot rolled steel sheet subjected to the hot-band annealing by the method according to  claim 11  is pickled without conducting mechanical descaling. 
     
     
         14 . A descaling method, characterized in that the Si-containing hot rolled steel sheet subjected to the hot-band annealing by the method according to  claim 12  is pickled without conducting mechanical descaling. 
     
     
         15 . A descaling method, characterized in that the Si-containing hot rolled steel sheet subjected to the hot-band annealing by the method according to  claim 11  is pickled after being subjected to mechanical descaling. 
     
     
         16 . A descaling method, characterized in that the Si-containing hot rolled steel sheet subjected to the hot-band annealing by the method according to  claim 12  is pickled after being subjected to mechanical descaling. 
     
     
         17 . The descaling method according to  claim 13 , wherein the Si-containing hot rolled steel sheet contains not less than 1.0 mass % of Si. 
     
     
         18 . The descaling method according to  claim 14 , wherein the Si-containing hot rolled steel sheet contains not less than 1.0 mass % of Si. 
     
     
         19 . The descaling method according to  claim 15 , wherein the Si-containing hot rolled steel sheet contains not less than 1.0 mass % of Si. 
     
     
         20 . The descaling method according to  claim 16 , wherein the Si-containing hot rolled steel sheet contains not less than 1.0 mass % of Si. 
     
     
         21 . The descaling method according to  claim 13 , wherein the Si-containing hot rolled steel sheet is a raw material for an electrical steel sheet. 
     
     
         22 . The descaling method according to  claim 14 , wherein the Si-containing hot rolled steel sheet is a raw material for an electrical steel sheet. 
     
     
         23 . The descaling method according to  claim 15 , wherein the Si-containing hot rolled steel sheet is a raw material for an electrical steel sheet. 
     
     
         24 . The descaling method according to  claim 16 , wherein the Si-containing hot rolled steel sheet is a raw material for an electrical steel sheet. 
     
     
         25 . The descaling method according to  claim 17 , wherein the Si-containing hot rolled steel sheet is a raw material for an electrical steel sheet. 
     
     
         26 . The descaling method according to  claim 18 , wherein the Si-containing hot rolled steel sheet is a raw material for an electrical steel sheet. 
     
     
         27 . The descaling method according to  claim 19 , wherein the Si-containing hot rolled steel sheet is a raw material for an electrical steel sheet. 
     
     
         28 . The descaling method according to  claim 20 , wherein the Si-containing hot rolled steel sheet is a raw material for an electrical steel sheet.