High silicon bearing dual phase steels with improved ductility

Abstract

A dual phase steel (martensite+ferrite) having a tensile strength of at least 980 MPa, and a total elongation of at least 15%. The dual phase steel may have a total elongation of at least 18%. The dual phase steel may also have a tensile strength of at least 1180 MPa. The dual phase steel may include between 0.5-3.5 wt. % Si, and more preferably between 1.5-2.5 wt. % Si.

What is claimed: 
     
         1 . A dual phase steel, said steel having a tensile strength of at least 980 MPa, and a total elongation of at least 15%. 
     
     
         2 . The dual phase steel of  claim 1 , wherein said steel has a total elongation of at least 18%. 
     
     
         3 . The dual phase steel of  claim 1 , wherein said steel has a tensile strength of at least 1180 MPa. 
     
     
         4 . The dual phase steel of  claim 1 , wherein said steel includes between 0.5-3.5 wt. % Si. 
     
     
         5 . The dual phase steel of  claim 4 , wherein said steel includes between 1.5-2.5 wt. % Si. 
     
     
         6 . The dual phase steel of  claim 5 , wherein said steel further includes between 0.1-0.3 wt. % C. 
     
     
         7 . The dual phase steel of  claim 6 , wherein said steel includes between 0.14-0.21 wt % C. 
     
     
         8 . The dual phase steel of  claim 7 , wherein said steel includes less than 0.19 wt. % C. 
     
     
         9 . The dual phase steel of  claim 7 , wherein said steel includes about 0.15 wt. % C. 
     
     
         10 . The dual phase steel of  claim 6 , wherein said steel further includes between 1-3 wt. % Mn. 
     
     
         11 . The dual phase steel of  claim 10 , wherein said steel includes between 1.75-2.5 wt % Mn. 
     
     
         12 . The dual phase steel of  claim 11 , wherein said steel includes about 1.8-2.2 wt % Mn. 
     
     
         13 . The dual phase steel of  claim 10 , wherein said steel further includes between 0.05-1 wt % Al. 
     
     
         14 . The dual phase steel of  claim 13 , wherein said steel further includes between 0.005-0.1 wt. % total of one or more elements selected from the group consisting of Nb, Ti, and V. 
     
     
         15 . The dual phase steel of  claim 10 , wherein said steel further includes between 0-0.3 wt. % Mo.