Process for producing steel components with highest stability and plasticity

Abstract

Processes for manufacture of metal components with high hardness and plasticity by deforming with high degree of deformation of metals, in particular steels, of which the deformation leads to a hardening by TWIP (Twinning Induced Plasticity) or SIP (Shearband Induced Plasticity) Effect, wherein the metal after the final step of annealing or crystallization annealing is deformed in at least one step into a semi finished product or the finished metal component, wherein the total elongation is in the range of 10 to 70%, as well as semi finished products, in particular continuous sheets, of steel with TWIP (Twinning Induced Plasticity) or SIP (Shearband Induced Plasticity) Effect, wherein the semi finished product exhibits a tensile strength of greater than 800 MPa and an elongation of greater than 35%.

1 . A process for manufacture of metal components or semi-finished products with high hardness and plasticity by the cold deforming of steel, wherein the degree of deformation lies at a total elongation in the range of 10 to 70%, comprising: 
 selecting a metal of which the deformation leads to a hardening by TWIP (Twinning Induced Plasticity) or SIP (Shearband Induced Plasticity) Effect, and    cold deforming following the last stage of annealing or crystallization annealing to the extent that a hardness increase of at least 30% of the start value is imparted and the residual tensile elongation of the metal is reduced by less than 20%.    
     
     
         2 . The process according to  claim 1 , wherein the cold deforming is carried out in a first step with an elongation of 10 to 60% and with a final deformation in a subsequent step with an elongation of less than 10%.  
     
     
         3 . The process according to  claim 1 , wherein the deforming is carried out as cold deforming with an elongation in at least one spatial direction of 10 to 35%.  
     
     
         4 . The process according to  claim 1 , wherein the deforming is carried out to the extent until a hardness increase of at least 300 MPa is imparted.  
     
     
         5 . The process according to  claim 1 , wherein the sum of the elongation of the deformation steps does not exceed 50%.  
     
     
         6 . The process according to  claim 1 , wherein the metal is selected from steels with the following composition (amounts in wt. %):  
       1 to 6 Si,  
       1 to 8 Al, and  
       10 to 30 Mn,  
       or  
       2 to 3.5 Si,  
       2 to 3.5 Al, and  
       12 to 30 Mn,  
       or  
       0.1 to 6 Si,  
       8 to 12 Al, wherein Al+Si>12,  
       18 to 35 Mn,  
       0.5 to 2 C, and  
       at least one of the elements Mg, Ga, Be being up to 3,  
       or  
       3 to 6 Si,  
       8 to 12 Al, wherein Al+Si>12,  
       18 to 35 Mn,  
       0.5 to 2 C,  
       at most 0.05 B,  
       at most 3 Ti and at least one of the elements Mg, Ga, Be with a content of respectively 0.3 to 3,  
       or  
       0.1 to 0.25 Si,  
       0 to 0.01 Al,  
       18 to 25 Mn,  
       0.4 to 0.9 C,  
       0 to 0.01 N,  
       or  
       0.05 to 1 Si,  
       0 to 0.008 Al,  
       15 to 30 Mn,  
       0.4 to 0.7 C,  
       0.001 to 0.01 N,  
       besides iron and conventional minor components of steel.  
     
     
         7 . The process according to  claim 1  or  2 , wherein the metal is steel with a duplex microstructure with austensitic and ferritic crystallites, or with a triplex microstructure with austensitic, ferritic and perovskite crystallites.  
     
     
         8 . A semi-finished product, or motor vehicle component produced by a process comprising: 
 selecting a metal of which deformation leads to a hardening by TWIP (Twinning Induced Plasticity) or SIP (Shearband Induced Plasticity) Effect, and    cold deforming following the last stage of annealing or crystallization annealing to the extent that a hardness increase of at least 30% of the start value is imparted and the residual tensile elongation of the metal is reduced by less than 20%,    wherein the semi-finished product exhibits a tensile strength of greater than 800 MPa and an elongation of greater than 35%.    
     
     
         9 . The semi-finished product or motor vehicle component according to  claim 8 , wherein it exhibits a tensile strength of greater than 1000 MPa and a elongation in the range of 35 to 55%.  
     
     
         10 . The semi-finished product or motor vehicle component according to  claim 8 , wherein the steel is pre-stretched by deforming in at least one spatial direction by 10 to 40%.