Method and apparatus for preparing steel stock before hot rolling

Abstract

A process and an apparatus for preparing steel stock before hot rolling. The steps of preheating the stock ( 5, 16, 22 ) in a first induction furnace ( 6 ) so that the preheated stock enters a subsequent descaling apparatus ( 7 ) with a surface temperature of T 1 ≧1000° C.; descaling the preheated stock by a plurality of water jets in a descaling apparatus ( 7 ); direct subsequent heating of the descaled stock in a second induction furnace ( 8 ), where the descaled stock enters the second induction furnace ( 8 ) at a temperature T 2 which is ≧T curie of the stock and heating in the second induction furnace 8 is either in a largely inert or largely reducing protective gas atmosphere; passing the heated stock in a rolling mill ( 9 ), where the heated stock enters the rolling mill ( 9 ) at a temperature 1220° C.≧T 3 1050° C.

1 . An apparatus for preparing steel rolling stock before hot rolling, comprising:
 a first induction furnace configured for preheating the rolling stock to a temperature T 1 ≧1000° C., the first induction furnace having an air atmosphere;   a descaling device following the first furnace and configured to receive the preheated rolling stock and to descale the preheated rolling stock, the descaling device comprising a plurality of water jets configured to descale the preheated rolling stock;   a second induction furnace following the descaling device and configured to receive the descaled rolling stock at T 2 ≧T Curie , and configured to heat the descaled rolling stock to a temperature 1220° C.≧T 3 ≧1050° C., the second furnace having a largely inert or largely reducing protective gas atmosphere therein; and   a rolling mill following the second furnace and configured to receive the rolling stock from the second furnace at T 3 , the rolling mill having at least three stands for hot rolling the heated rolling stock.   
     
     
         2 . The apparatus as claimed in  claim 1 , wherein the descaling device includes at least one rotary descaling device respectively on a top and on a bottom side of the rolling stock. 
     
     
         3 . The apparatus as claimed in  claim 1 , further comprising:
 a controller; and   a measuring instrument connected to the controller, being located between the first induction furnace and the descaling device and configured for measuring a temperature or a temperature profile of the rolling stock, the measuring instrument being so connected with the controller and the controller being connected to at least one inductor of the first induction furnace for controlling the at least one inductor.   
     
     
         4 . The apparatus as claimed in  claim 1 , further comprising:
 a controller; and   a measuring instrument connected to the controller, being located between the second induction furnace and the rolling mill and configured for measuring a temperature or a temperature profile of the rolling stock, the measuring instrument being so connected with the controller and the controller being connected to at least one inductor of the second induction furnace for controlling the at least one inductor.   
     
     
         5 . The apparatus as claimed in  claim 1 , wherein a distance between an outlet opening of the first induction furnace and the descaling device is a maximum distance of 7 m. 
     
     
         6 . The apparatus as claimed in  claim 1 , wherein a distance between an outlet opening of the second induction furnace and a roll gap of the first rolling stand of the rolling mill is a maximum distance of 7 m. 
     
     
         7 . A combined casting/rolling plant for producing strip steel, the plant having a roughing train and a finishing train; and
 the apparatus as claimed in  claim 1  is arranged between the roughing train and the finishing train of the plant.   
     
     
         8 . The combined casting/rolling plant as claimed in  claim 7 , further comprising a combined ISP casting/rolling plant for producing strip steel, wherein the apparatus is arranged between a heatable coilbox and the finishing train of the plant.