High performance high strength low alloy wrought steel
AssigneeFerrous Wheel Group Inc.
InventorBanagaru V. N. Rao
Life of this patent
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Abstract
A high strength, low alloy, low to medium carbon structural steel is provided of the Fe/Cr/C type, said steel characterized by the presence of a small but effective amount of each of Cu and Ni sufficient to enhance the mechanical stability of retained austenite formed following quenching of said steel from its austentizing temperature. Preferably the steel also includes small but effective amounts a Al, Ti and Nb suficient to provide a fine grained microstructure.
Claims16
A fine grained, high strength, tough, low alloy, low to medium carbon wrought steel having an ultimate tensile strength of about at least 200 ksi, said steel having a microstructure in which soft and tough austenite films surround lath martensite, and consisting essentially by weight of about 0.5 to 4% Cr, about 0.05 to 0.5% C, about 0.5 to 2% Mn, about 0.1 to 2% Cu, about 0.1 to 3% Ni, about 0.01 to 0.05% Al, about 0.005 to 0.02% Ti, about 0.005 to 0.03% Nb and the balance essentially iron including minor amounts of tramp elements P, S, Si, and N, the amount of Si not exceeding about 0.1%, said steel being characterized by an average grain size of less than about 50 microns.
As an article of manufacture, a fine grained wrought steel component comprised of a high strength at least 200 ksi, low alloy, low to medium carbon steel, said steel having a microstructure in which soft and tough austenite films surround lath matensite, and consisting essentially by weight of about 0.5 to 4% Cr, about 0.05 to 0.5% C, about 0.5 to 2% Mn, about 0.1 to 2% Cu, about 0.1 to 3% Ni, about 0.01 to 0.05% Al, about 0.005 to 0.02% Ti, and about 0.005 to 0.03% Nb, and the balance being essentially iron containing minor amounts of tramp elements P, S, Si, and N, the amount of Si not exceeding about 0.1%, said steel being characterized by a fine average grain size of less than about 50 microns.
A fine grained, high strength, tough, low alloy, low to medium carbon wrought steel in the hardened condition having an ultimate tensile strength of about at least 200 ksi, said steel having a microstructure in which soft and tough austenite films surround lath martensite, and consisting essentially by weight of about 0.5 to 4% Cr, about 0.05 to 0.5% C, about 0.5 to 2% Mn, about 0.1 to 2% Cu, about 0.1 to 3% Ni, about 0.01 to 0.05% Al, about 0.005 to 0.02% Ti, about 0.005 to 0.03% Nb and the balance essentially iron including minor amounts of tramp elements P, S, Si, and N, the amount of Si not exceeding about 0.1%, said steel in the hardened condition being characterized by a microstructure of lath martensite surrounded by a layer of retained austenite.
A fine grained, high strength, tough, low alloy, low to medium wrought carbon steel in the hardened condition having a ultimate tensile strength of about at least 200 ksi, said steel having a microstructure in which soft and tough austenite films surround lath martensite, and consisting essentially by weight of about 1.8 to 2.4% Cr, about 0.2 to 0.25% C, about 1.4 to 1.6% Mn, about 0.25 to 0.5% Cu, about 0.2 to 0.5% Ni, about 0.02 to 0.05% Al, about 0.005 to 0.02% Ti, about 0.005 to 0.03% Nb and the balance being essentially iron including minor amounts of tramp elements P, S, Si, and N, the amount of Si not exceeding about 0.1%, said steel in the hardened state being characterized by a microstructure of lath martensite surrounded by a layer of retained austenite.
Dependencies are inferred from the claim text.