Edge formability in metallic alloys

Abstract

This disclosure is directed at mechanical property improvement in a metallic alloy that has undergone one or more mechanical property losses as a consequence of forming an edge, such as in the formation of an internal hole or an external edge. Methods are disclosed that provide the ability to improve mechanical properties of metallic alloys that have been formed with one or more edges placed in the metallic alloy by a variety of methods which may otherwise serve as a limiting factor for industrial applications.

1 . A cold rolled steel sheet product comprising Fe and at least four alloying elements selected from Si, Mn, B, Cr, Ni, Cu and C, wherein the steel sheet product includes a sheared edge, has an ultimate tensile strength of at least 799 MPa, a total elongation of at least 6.6 percent, and a hole expansion ratio greater than 20. 
     
     
         2 . The steel sheet product of  claim 1 , wherein the steel sheet product comprises at least five of the elements selected from Si, Mn, B, Cr, Bi, Cu and C. 
     
     
         3 . The steel sheet product of  claim 1 , wherein the steel sheet product comprises at least six of the elements selected from Si, Mn, B, Cr, Ni, Cu and C. 
     
     
         4 . The steel sheet product of  claim 1 , wherein the steel sheet product comprises Fe, Si, Mn, B, Cr, Ni, Cu and C. 
     
     
         5 . The steel sheet product of  claim 1 , wherein the steel sheet product has a yield strength of at least 400 MPa. 
     
     
         6 . The steel sheet product of  claim 1 , wherein the sheared edge comprises an internal hole and/or an external edge. 
     
     
         7 . The steel sheet product of  claim 1 , wherein the sheared edge is formed by punching, piercing, perforating, cutting, cropping, EDM cutting, waterjet cutting, laser cutting, or milling. 
     
     
         8 . The steel sheet product of  claim 1 , wherein the steel sheet product is annealed. 
     
     
         9 . The steel sheet product of  claim 8 , wherein the sheared edge has been subjected to annealing after formation of the sheared edge. 
     
     
         10 . The steel sheet product of  claim 8 , wherein the steel sheet product has been subjected to annealing prior to formation of the sheared edge. 
     
     
         11 . The steel sheet product of  claim 1 , wherein the sheared edge is formed in a progressive die stamping operation. 
     
     
         12 . The steel sheet product of  claim 1 , wherein the sheared edge of the steel sheet product is positioned in a vehicle. 
     
     
         13 . The steel sheet product of  claim 1 , wherein the sheared edge of the steel sheet product is part of a vehicular frame, vehicular chassis, or vehicular panel.