Method for thermo-mechanically controlled process for high toughness beam production

Abstract

The invention provides a method to obtain a high strength and high toughness yield during production of steel beams by developing a metallurgical model, the method comprising at a tandem mill. In particular, the method comprises rolling a steel beam blank above a non-recrystallization temperature and enhance the RCR value, the beam blank having an austenite grain structure to obtain a rolled beam; and rolling the rolled beam below the non-recrystallization temperature to obtain critical strain accumulation for increased austenite grain refinement to achieve certain CCR value, wherein the non-recrystallization temperature (T nr ). Also provided is a computer implemented method of determining the impact of changes to process parameters on the resulting product.

What is claimed is: 
     
         1 . A method to obtain a high strength and high toughness yield during production of steel beams, the method comprising:
 at a tandem mill,
 rolling a steel beam blank above a non-recrystallization temperature, the beam blank having an austenite grain structure to obtain a rolled beam; 
 rolling the rolled beam below the non-recrystallization temperature to obtain critical strain accumulation for increased austenite grain refinement, wherein the non-recrystallization temperature (T nr ) is determined by
     Tnr= 887+464*(% C)+6645*(% Nb)−664*√{square root over (% Nb)}+732*(% V)−230*√{square root over (% V)}+890*(% Ti)+363*(% Al)−357*(% Si)
 
 
   
       wherein C: Carbon content in steel (in wt %), Nb: Niobium content in steel (in wt %), V: Vanadium content in steel (in wt %), Ti: Titanium content in steel (in wt %), Al: Aluminium content in steel (in wt %), Si: Silicon content in steel (in wt %). 
     
     
         2 . The method of  claim 1 , wherein cooling rate is controlled to obtain a specific ferrite grain size. 
     
     
         3 . The method of  claim 2 , wherein at least one of the following is optimized accumulated strain at least stand, type of recrystallization, recrystallized grain size and precipitation kinetics. 
     
     
         4 . The method of  claim 3 , wherein entry and exit thickness for a mill stand is set to optimize accumulated strain at the least stand. 
     
     
         5 . The method of  claim 1 , wherein the beam at least partially includes direct reduced iron. 
     
     
         6 . The method of  claim 1 , wherein the beam blank is a specific size and shape, optional BB3b. 
     
     
         7 . A computer implemented method for execution at a data storage device, the method comprising:
 providing at least one input parameter in relation to beam rolling;   outputting at least one rolling parameter for beam rolling to achieve target metallurgical properties.   
     
     
         8 . The method of  claim 7 , wherein the at least one input parameter includes at least one of:
 a roll diameter,   a roll stand,   a relation speed,   a relation stand   a roll force stand,   a deformation temperature stand,   a flange thickness,   a flange stand,   a number of stands,   a roll material, or   a roll stand.   
     
     
         9 . The method of  claim 7 , wherein the at least one rolling parameter includes a set of rolling parameters. 
     
     
         10 . The method of  claim 9 , wherein the set of rolling parameters includes at least one of:
 a required chemistry to achieve the target metallurgical properties,   a production cost,   a recommended reheating temperature,   a fraction softening,   a fraction stand,   a grain size,   a grain stand,   a final austenite grain size,   a ferrite grain size,   a recrystallization controlled rolling austenite,   a conventional controlled rolling austenite, or   a conventional controlled rolling ferrite.   
     
     
         11 . The method of  claim 9 , wherein calculation of a stand includes the difference between entry and exit stands of a beam flange. 
     
     
         12 . The method of  claim 9 , wherein a beam is formed from a specific beam blank size. 
     
     
         13 . The method of  claim 12 , where the specific beam blank size is BB3b. 
     
     
         14 . The method of  claim 12 , wherein a range for a thickness of a beam flange is between 58 mm and 77 mm.