Method for optimally producing metal steel and iron alloys in hot-rolled and thick plate factories using a microstructure simulator, monitor, and/or model

Abstract

In a method for controlling a metallurgical production plant by means of a microstructure model, which comprises a program which calculates at least one mechanical strength property of a product being produced, which program calculates the strength property on the basis of calculated metallurgical phase components of the microstructure of the produced product, wherein the metallurgical plant comprises a terminating cooling line, and wherein operating parameters for the metallurgical plant with adjustable output values, which are established at least partially in advance, are factored into the calculation of the mechanical strength property, the object of the method is to enable an advantageous adjustment of operating parameters in order to achieve desired mechanical strength properties in a product consisting of a metal steel and/or iron alloy. This object is achieved in that, as the operating parameters that are factored into the calculation of the strength property, the mass fraction of at least one alloy element that is present in the chemical composition of the metal steel and/or iron alloy being used, and at least one additional operating parameter, preferably a cooling rate which is set as part of a cooling process carried out after a rolling process, are detected, and an increase in the strength property in question of the produced product, said increase being achieved by modifying at least said additional operating parameter, is at least partially compensated for by reducing the mass fraction of one or more of the alloying elements of the metal steel and/or iron alloy being used.

1 - 4 . (canceled) 
     
     
         5 . The method according to  claim 14 , characterized in that the program comprises a mathematical term and/or algorithm for expressing the impact of mass fractions of alloying elements in the chemical composition of the metal steel and/or iron alloy being used on the yield strength of the finished product. 
     
     
         6 . The method according to  claim 5 , characterized in that the term has the equation
   ΔYS=ΣA i C i   B     i   .
   
     
     
         7 . The method according to  claim 14 , characterized in that the program comprises a term in the form of the equation d which expresses the impact of the ferrite grain size (d) of the ferrite microstructure that forms during a final cooling of the product on yield strength 
       
         
           
             
               
                 Δ 
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                  
                 YS 
               
               = 
               
                 A 
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                     1 
                     
                       d 
                     
                   
                   . 
                 
               
             
           
         
       
     
     
         8 . The method according to  claim 14 , characterized in that the program comprises a term in the form of the equation which expresses the impact of the cooling rate on the ferrite grain size (d a ) of the ferrite microstructure that forms during a final cooling of the product d a =(A 1 −A 2 ·C eq   A     2   )·d y   0.3−ε     0.5   ·CR −0.15 . 
     
     
         9 . The method according to  claim 14 , characterized in that the program is used to optimize the operating parameters, at least with respect to the at least one mechanical strength property to be achieved. 
     
     
         10 . The method according to  claim 14 , characterized in that the at least one mechanical strength property which is calculated in each case is displayed online at a control station for the metallurgical production plant. 
     
     
         11 . The method according to  claim 14 , characterized in that the calculated at least one mechanical strength property is used to control the operating parameters of the metallurgical production plant, and to automatically select the desired at least one mechanical strength property. 
     
     
         12 . The method according to  claim 14 , characterized in that the metallurgical production plant has a process chain which comprises a furnace, a rolling mill, in particular the hot rolling and/or heavy plate mill, and a cooling line, and in that operating parameters for the entire process chain of said metallurgical production plant are factored into the program. 
     
     
         13 . The method according to  claim 14 , characterized in that the metallurgical production plant comprises a zone, in particular a steel mill and/or a continuous casting line, in which the metal steel and/or iron alloy is in molten form, and in that operating parameters for the entire process chain of the metallurgical production plant that comprises this zone are factored into the program. 
     
     
         14 . A method for controlling a metallurgical production plant for producing a product from a metal steel and/or iron alloy, wherein the production process is controlled at least in part by means of a microstructure simulator and/or microstructure monitor and/or microstructure model, which comprises a program which calculates at least one mechanical strength property of the produced product containing the metal steel and/or iron alloy, and which calculates the at least one mechanical strength property dependent on a relevant process chain on the basis of calculated metallurgical phase components and/or the proportions of each of these phase components in the resulting metallurgical microstructure of the produced product, wherein the process chain of the metallurgical production plant comprises a hot rolling and/or heavy plate rolling plant having a terminating cooling line, and wherein operating parameters for the metallurgical production plant, on which the resulting at least one mechanical strength property depends, along with adjustable output values, at least some of which are defined in advance, are factored into the calculation of the at least one mechanical strength property,
 characterized in that   as the operating parameters of the metallurgical production plant that are factored into the calculation of the at least one strength property, the mass fraction of at least one alloy element, preferably all alloy elements, that is/are present in the chemical composition of the metal steel and/or iron alloy being used, and as an additional operating parameter, a cooling rate which is adjusted as part of a cooling process carried out after a rolling process, is detected, and an increase in the strength property in question of the finished product, said increase being achieved by changing said at least additional operating parameter, in particular by increasing the cooling rate, is at least partly compensated and/or offset by reducing the mass fraction of one or more of the alloying elements in the chemical composition of the metal steel and/or iron alloy being used,   wherein the mass fraction of each alloying element(s) detected in each case, and the cooling rate detected in each case, are assigned a countable numerical value using a valuation unit that represents a valuation standard, and the program calculates and/or displays the total values of each of the countable valuation units that are obtained for each strength property in question with different combinations of a mass fraction of alloying agent(s), valued as a number of countable valuation units, and a cooling rate valued as a number of countable valuation units, and   wherein the program comprises a mathematical term and/or algorithm by means of which the respective number of valuation units and/or the various calculated total values are compared.