Method for Producing a Hot-Rolled Flat Steel Product

Abstract

A method for generating a flat steel product comprising the steps of: melting a steel melt, comprising, in addition to Fe and unavoidable impurities (in wt %) C: 0.5-1.3%, Mn: 18-26%, Al: 5.9-11.5%, Si: <1%, Cr: <8%, Ni: <3%, Mo: <2%, N: <0.1%, B: <0.1%, Cu: <5%, Nb: <1%, Ti: <1%, V: <1%, Ca: <0.05%, Zr: <0.1%, P: <0.04%, S: <0.04%; casting the steel melt into a cast strip; heating the cast strip to an initial hot-rolling temperature of 1100-1300° C. at a heating rate of at least 20 K/s; hot rolling the cast strip into a hot strip; cooling the hot strip within 10 seconds after the hot rolling at a cooling rate of at least 100 K/s to <400° C.; and winding the cooled hot strip into a coil at a coiling temperature of up to 400° C.

1 . A method for producing a hot-rolled flat steel product comprising the following working steps:
 melting a steel melt, comprising, in addition to iron and unavoidable impurities (in wt %)
 C: 0.5-1.3%, 
 Mn: 18-26%, 
 Al: 5.9-11.5%, 
 Si: less than 1%, 
 Cr: less than 8%, 
 Ni: less than 3%, 
 Mo: less than 2%, 
 N: less than 0.1%, 
 B: less than 0.1%, 
 Cu: less than 5%, 
 Nb: less than 1%, 
 Ti: less than 1%, 
 V: less than 1%, 
 Ca: less than 0.05%, 
 Zr: less than 0.1%, 
 P: less than 0.04%, 
 S: less than 0.04%, 
   casting the steel melt into a cast strip,   heating the cast strip to an initial hot-rolling temperature of 1100-1300° C. at a heating rate of at least 20 K/s,   hot rolling the cast strip heated to the initial hot-rolling temperature into a hot strip,   cooling of the hot strip, the cooling starting within 10 seconds after the hot rolling at a cooling rate of at least 100 K/s to <400° C.,   winding the cooled hot strip into a coil at a coiling temperature of up to 400° C.   
     
     
         2 . The method according to  claim 1 , wherein the steel melt contains (in wt. %) 0.1-0.4% Si, <3.0% Cr, <1.0% Ni, <0.5% Mo, 0.005-0.04% N, <0.0050% B, <1% Cu, <0.2% Nb, <0.3% Ti, <0.3% V, <0.005% Ca, <0.005% Zr, 0.01-0.03% P or 0.005-0.02% S. 
     
     
         3 . The method according to  claim 1 , wherein the casting of the steel melt into a cast strip is performed in a two roller casting machine. 
     
     
         4 . The method according to  claim 1 , wherein the thickness of the cast strip is a maximum of 5 mm. 
     
     
         5 . The method according to  claim 1 , wherein the heating to the initial hot rolling temperature is performed by means of an inductively operating heating device. 
     
     
         6 . The method according to  claim 1 , wherein the initial hot rolling temperature, to which the cast strip is heated, is at least 1150° C. 
     
     
         7 . The method according to  claim 1 , wherein a degree of deformation achieved in the course of the hot rolling is at least 10%. 
     
     
         8 . The method according to  claim 1 , wherein a final hot rolling temperature of the hot rolling is 1000-1050° C. 
     
     
         9 . The method according to  claim 1 , wherein the hot rolling takes place in a single pass. 
     
     
         10 . The method according to  claim 1 , wherein the cooling of the hot strip begins within 10 seconds of the end of hot rolling. 
     
     
         11 . The method according to  claim 1 , wherein the working steps performed prior to hot rolling are carried out under a protective atmosphere. 
     
     
         12 . The method according to  claim 1 , further comprising hot strip annealing the hot strip obtained at an annealing temperature of 900-1150° C. 
     
     
         13 . The method according to  claim 12 , wherein the Al content of the cast strip is at least 10 wt. %. 
     
     
         14 . The method according to  claim 1 , further comprising cold-rolling the hot strip into a cold strip. 
     
     
         15 . The method according to  claim 1 , wherein a degree of deformation achieved in the course of the hot rolling is 10-20%.