Method, Device and System for the Heat Treatment of a Moving Metal Strip

Abstract

The invention relates to a method for the heat treatment of a running metal strip, which comprises: a heating step for heating the strip; a step for cooling the heated strip; and conductive heat transfer from at least one segment of the strip which is being cooled to at least one segment of the strip which is being heated, so that at least part of each of said cooling and heating steps is carried out on the strip. The invention also relates to a heat transmission device for implementing said method and having at least one thermally conductive solid element, such as for example a roll, and to a system for the heat treatment of a running metal strip that incorporates such a device.

1 . A method for the heat treatment of a moving metal strip, comprising:
 heating of the strip,   cooling of the heated strip, and   transfer of heat from at least one segment of the strip being cooled to at least one segment of the strip being heated, so as to effect at least part of each of the said cooling and heating of the strip,   and characterised in that the said heat transfer takes place mainly by conduction.   
   
   
       2 . A method according to  claim 1 , wherein the said heat transfer is effected from a plurality of segments of the strip being heated to a plurality of segments of the strip being cooled in reverse order in the direction of travel of the strip. 
   
   
       3 . A method according to  claim 1 , wherein, in the said step of heating the strip, the strip is also heated by a heat source external to the strip. 
   
   
       4 . A method according to  claim 1 , wherein the said heat transfer is effected by means of at least one heat-conducting solid element in contact with a segment of the strip being heated and a segment of the strip being cooled. 
   
   
       5 . A method according to  claim 4 , wherein the said at least one heat-conductive solid element is in the form of a roller, preferably metal. 
   
   
       6 . A method according to  claim 5 , wherein the segment of the strip being cooled is in contact with the said roller at a contact angle of at least 20°, preferably at least 30°. 
   
   
       7 . A method according to  claim 5 , wherein the segment of the strip being heated is in contact with the said roller at a contact angle of at least 20°, preferably at least 30°. 
   
   
       8 . A method according to  claim 1 , wherein the difference in temperature between a segment of the metal strip being cooled and a segment of the strip being heated between which at least part of the heat transfer takes place by conduction is at least 200° C. 
   
   
       9 . A method according to  claim 1 , wherein the difference in temperature between a segment of the metal strip being cooled and a segment of the strip being heated between which at least part of the said heat transfer takes place by conduction is below 500° C. 
   
   
       10 . A heat transmission device for simultaneously heating a moving metal strip upstream of a main heating zone and cooling it downstream of the said main heating zone, characterised in that it comprises at least one heat-conductive solid element that is in contact with the said metal strip both upstream and downstream of the main heating zone, so as to transfer heat by conduction between at least one segment of the metal strip downstream and at least one segment of the metal strip upstream. 
   
   
       11 . A device according to  claim 10 , comprising a series of several heat-conductive solid elements for successively contacting the said metal strip upstream and, in reverse order in the direction of travel of the strip, downstream of the main heating zone, so as to transfer heat by conduction between segments of the metal strip downstream and segments of the metal strip upstream. 
   
   
       12 . A device according to  claim 10 , wherein said at least one heat-conductive solid element is in the form of a roller, preferably metal. 
   
   
       13 . A device according to  claim 10 , also comprising at least one deflector roller in order to define a contact angle between the said metal strip upstream and/or downstream of the main heating zone and the said heat-conductive solid element in the form of a roller. 
   
   
       14 . A system for the continuous heat treatment, in particular annealing, of a moving metal strip, comprising a main heating zone and a heat transmission device according to  claim 10 . 
   
   
       15 . A method according to  claim 6 , wherein the segment of the strip being heated is in contact with the said roller at a contact angle of at least 20°, preferably at least 30°. 
   
   
       16 . A device according to  claim 11 , wherein said at least one heat-conductive solid element is in the form of a roller, preferably metal. 
   
   
       17 . A device according to  claim 11 , also comprising at least one deflector roller in order to define a contact angle between the said metal strip upstream and/or downstream of the main heating zone and the said heat-conductive solid element in the form of a roller. 
   
   
       18 . A device according to  claim 12 , also comprising at least one deflector roller in order to define a contact angle between the said metal strip upstream and/or downstream of the main heating zone and the said heat-conductive solid element in the form of a roller. 
   
   
       19 . A system for the continuous heat treatment, in particular annealing, of a moving metal strip, comprising a main heating zone and a heat transmission device according to  claim 11 . 
   
   
       20 . A system for the continuous heat treatment, in particular annealing, of a moving metal strip, comprising a main heating zone and a heat transmission device according to  claim 12 .