Triple-phase nano-composite steels
AssigneeMMFX Technologies Corporation
InventorsGrzegorz J. Kusinski, David Pollack, Gareth Thomas
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Abstract
Carbon steels of high performance are disclosed that contain a three-phase microstructure consisting of grains of ferrite fused with grains that contain dislocated lath structures in which laths of martensite alternate with thin films of austenite. The microstructure can be formed by a unique method of austenization followed by multi-phase cooling in a manner that avoids bainite and pearlite formation and precipitation at phase interfaces. The desired microstructure can be obtained by casting, heat treatment, on-line rolling, forging, and other common metallurgical processing procedures, and yields superior combinations of mechanical and corrosion properties.
Claims11
An alloy carbon steel comprising iron and a maximum of 0.35% by weight of carbon, said alloy carbon steel having a triple-phase microstructure comprising ferrite crystals fused with martensite-austenite crystals, said crystals having grain sizes within the range of about 2 microns to about 100 microns, said martensite-austenite crystals comprising laths of martensite alternating with thin films of austenite, said martensite-austenite crystals constituting from about 5% to about 95% by weight of said triple-phase microstructure, and said martensite-austenite crystals devoid of carbide precipitates at interfaces between phases.
Dependencies are inferred from the claim text.