Abstract: An age hardenable martensitic steel alloy having a unique combination of very high strength and good toughness consists essentially of, in weight percent, about______________________________________ C 0.21-0.34 Mn 0.20 max. Si 0.10 max. P 0.008 max. S 0.003 max. Cr 1.5-2.80 Mo 0.90-1.80 Ni 10-13 Co 14.0-22.0 Al 0.1 max. Ti 0.05 max. Ce 0.030 max. La 0.010 max. ______________________________________the balance essentially iron. In addition, cerium and sulfur are balanced so that the ratio Ce/S is at least about 2 and not more than about 15. A small but effective amount of calcium can be present in place of some or all of the cerium and lanthanum.

Abstract: A martensitic steel alloy has a unique combination of hardness and corrosion resistance. Broadly stated, the alloy contains, in weight percent, about______________________________________ C 1.40-1.75 Mn 0.30-1.0 Si 0.80 max. P 0.020 max. S 0.015 max. Cr 13.5-18.0 Ni 0.15-0.65 Mo 0.40-1.50 V 1.0 max. N 0.02-0.08 ______________________________________and the balance essentially iron. The alloy is balanced within the stated weight percent ranges such that the ratio %Cr:%C is about 10.0-11.0 and the sum %Ni+%Mn is at least about 0.75. The alloy can be hardened to at least about 60 HRC from a wide range of solution treating temperatures and provides corrosion resistance that is similar to Type 440C alloy.

Abstract: A high strength, high fracture toughness steel alloy consisting essentially of, in weight percent, about______________________________________ C 0.2-0.33 Mn 0.20 max. Si 0.1 max. P 0.008 max. S 0.004 max. Cr 2-4 Ni 10.5-15 Mo 0.75-1.75 Co 8-17 Ce Effective amount-0.030 La Effective amount-0.01 Fe Balance ______________________________________and an article made therefrom are disclosed. A small but effective amount of calcium can be present in this alloy in substitution for some or all of the cerium and lanthanum. The alloy is an age-hardenable martensitic steel alloy which provides a unique combination of tensile strength and fracture toughness. The alloy provides excellent mechanical properties when hardened by vacuum heat treatment with inert gas cooling and has a low ductile-to-brittle transition temperature.

Abstract: A high strength, high fracture toughness structural steel alloy consisting essentially of, in weight percent, about______________________________________ C 0.2-0.33 Cr 2-4 Ni 10.5-15 Mo 0.75-1.75 Co 8-17 Fe Balance ______________________________________and an article made therefrom are disclosed. The alloy is an age-hardenable martensitic steel alloy whcih provides a unique combination of tensile strength and fracture toughness. The alloy provides excellent mechanical properties when hardened by vacuum heat treatment with inert gas cooling and has a low ductile-to-brittle transition temperature.

Abstract: This invention provides a case hardening steel alloy and articles made therefrom which, when case hardened and heat treated, have high case hardness, corrosion resistance, high temperature capability and metal-to-metal wear resistance and high core ductility, impact toughness and fracture toughness. The alloy contains about 0.05-0.1 w/o C, 0.04 w/o max. N, 1.5 w/o max. Mn, 1 w/o max. Si, 11-15 w/o Cr, 1-3 w/o Mo, 1.5-3.5 w/o Ni, 3-8 w/o Co, 0.1-1 w/o V, and the balance Fe. In a preferred embodiment, the alloy is balanced according to Equation 1 (Eq.1) so that:______________________________________ 3(w/o Cr) + 6(w/o Si) + 2.5 (w/o Mo) + 6(w/o V) - 25(w/o C + N) - 6(w/o Ni) - 2(w/o Mn) - 2(w/o Co) - 21 .ltoreq. 0.

Abstract: An improved hot work tool steel has higher hardness capability and better temper resistance above 1100 F. and better wear resistance than AISI type H13 and better toughness and ductility then AISI type H10 or type H21. The steel alloy contains essentially the following in weight percent:______________________________________ Carbon 0.55 Max. Manganese 1.5 Max. Silicon 2.0 Max. Chromium 3.5-6.0 Molybdenum 1.5-3.0 Vanadium 0.50-1.50 ______________________________________and the balance is essentially iron except for the usual impurities found in commerical grades of hot work tool steels. Carbon and chromium are balanced within the composition such that% carbon.gtoreq.0.098.times.% chromium.

Abstract: A hot work tool steel has high hardness capability and improved toughness when air cooled in section sizes of 6 inches (15.24 cm) or larger. The alloy steel which is deep air hardenable, has good dimensional stability and exceptional wear resistance, in its broad scope consists essentially of about 0.35-0.6 w/o carbon, 1.0 w/o max. manganese, 2.0 w/o max. silicon, 5.7-7.0 w/o chromium, 1.65-2.2 w/o molybdenum, 0.6-1.1 w/o vanadium, and the balance is iron except for the usual impurities found in commercial grades of such alloy steels.

Abstract: A low cobalt maraging steel has a yield strength of at least about 240 ksi (about 1655 MPa) in the aged condition in combination with good toughness as indicated by a longitudinal Charpy V-notch impact toughness of at least aobut 20 ft-lb (about 27 J), as well as good notch ductility. The alloy contains, in weight percent, about:______________________________________ w/o ______________________________________ C 0.02 Max. Ni 15-20 Mo 0.50-4.0 Co 0.5-5.0 Ti 0.90-1.35 Nb 0.03-0.35 Al 0.3 Max. B Up to 0.015 ______________________________________The balance is essentially iron, optional additions, and the usual impurities found in commercial grades of high nickel, low carbon maraging steels. The alloy is further characterized in that the ratio %Co:%Mo is at least about 0.3 and %Ti+%Nb.gtoreq.1.0.