Patent ID: 7118637

Claim:
A process for manufacturing a high-strength, corrosion-resistant tough alloy carbon steel, said process comprising: (a) forming a carbon steel alloy composition having a martensite start temperature of at least about 350° C.; (b) heating said carbon steel alloy composition to a temperature sufficient to cause said alloy composition to assume a homogeneous austenite phase with all alloying elements in solution; (c) treating said homogeneous austenite phase while said austenite phase is above its austenite recrystallization temperature to achieve a grain size of about 5 to 9 microns; and (d) cooling said austenite phase through said martensite transition range to convert said austenite phase to a microstructure of fused grains, each grain having a diameter of about 5 to 9 microns, and containing laths of martensite alternating with films of retained austenite in a uniform orientation throughout said grain and any carbides present in said alloy carbon steel are precipitates of less than 500 Å in diameter.