Ati Properties, Inc.

Allegheny Ludlum Corporation

Thomas R Parayil

Ronald E Bailey

Glenn J Swiatek

Tong C Lee

Timothy M Hackett

David S Bergstrom

Njall Stefansson

David R Hasek

Bradley Hasek

Raymond A Painter

Andrew Nichols

One aspect of the present disclosure is directed to low-alloy steels exhibiting high hardness and an advantageous level of multi-hit ballistic resistance with minimal crack propagation imparting a level of ballistic performance suitable for military armor applications. Certain embodiments of the steels according to the present disclosure have hardness in excess of 550 HBN and demonstrate a high level of ballistic penetration resistance relative to conventional military specifications.

Methods for making high hardness, high toughness iron-base alloys

An air hardenable steel alloy is disclosed comprising, in percent by weight: 0.18 to 0.26 carbon; 3.50 to 4.00 nickel; 1.60 to 2.00 chromium; 0 to 0.50 molybdenum; 0.80 to 1.20 manganese; 0.25 to 0.45 silicon; 0 to less than 0.005 titanium; 0 to less than 0.020 phosphorus; 0 up to 0.005 boron; 0 up to 0.003 sulfur; iron; and impurities. The air hardenable steel alloy has a Brinell hardness in a range of 352 HBW to 460 HBW. The air hardenable steel alloy combines high strength, medium hardness and toughness, as compared with certain known air hardenable steel alloys, and finds application in, for example, any of a steel armor, a blast-protective hull, a blast-protective V-shaped hull, a blast-protective vehicle underbelly, and a blast-protective enclosure.

Air hardenable shock-resistant steel alloys, methods of making the alloys, and articles including the alloys

An aspect of the present disclosure is directed to low-alloy steels exhibiting high hardness and an advantageous level of multi-hit ballistic resistance with low or no crack propagation imparting a level of ballistic performance suitable for military armor applications. Various embodiments of the steels according to the present disclosure have hardness in excess of 550 BHN and demonstrate a high level of ballistic penetration resistance relative to conventional military specifications.

High hardness, high toughness iron-base alloys and methods for making same

Maraging steel compositions, methods of forming the same, and articles formed therefrom comprising, by weight, 15.0 to 20.0% Ni, 2.0 to 6.0% Mo, 3.0 to 8.0% Ti, up to 0.5% Al, the balance Fe and residual impurities. The composition may be a first layer of a composite plate, and may have a second layer deposited on the first layer, the second layer having a composition comprising, by weight, 15.0 to 20.0% Ni, 2.0 to 6.0% Mo, 1.0 to 3.0 Ti, up to 0.5% Al, the balance Fe and residual impurities. The first layer may have a hardness value ranging from 58 to 64 RC, and the second layer may have a hardness value ranging from 48 to 54 RC. The first layer may be formed employing powdered metallurgical techniques. Articles formed from the compositions include armored plate.

Steel compositions, methods of forming the same, and articles formed therefrom

The present disclosure provides alloys having an ultra-low coefficient of thermal expansion in the range of 60&#xb0; F. to 80&#xb0; F. The alloys have coefficient of thermal expansion no greater than 0.35&#xd7;10&#xb0; F.in the range of 60&#xb0; F. to 80&#xb0; F. Methods of making such alloys also are provided, as well articles of manufacture including such alloys and methods of making such articles.

Method of making alloys having low coefficient of thermal expansion

A process for producing a steel includes subjecting at least a portion of a melt of the steel to electroslag remelting and, in a subsequent step, heating the steel to a temperature at least as great as the lowest temperature at which all carbides that can form in the remelted steel will dissolve and no greater than the nil ductility temperature of the of the remelted steel, and maintaining the temperature for a period of time sufficient to dissolve primary and clustered carbide particles in the remelted steel greater than 15 micrometers in length. A novel martensitic stainless steel also is disclosed including 0.65 to 0.70 carbon; 0 to 0.025 phosphorus; 0 to 0.020 sulfur; 0.20 to 0.50 silicon; at least one of greater than 0.0004 boron and greater than 0.03 nitrogen; 0.45 to 0.75 manganese; 12.7 to 13.7 chromium; and 0 to 0.50 nickel.

Steelmaking process

A pressure-bonded composite material includes at least one layer of a stabilized low carbon steel core material and one layer of a stainless steel joined at an interface, wherein the stabilized carbon steel includes columbium (niobium) and at least one other carbide-forming element in amounts effective to prevent carbon migration from the carbon steel to the stainless steel and the composite material has a physical grain size no larger than ASTM #6.

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New Kensington, PA, United States of America

Thomas R Parayil