HIGH-STRENGTH WELDABLE STEEL AT ENHANCED HARDENABILITY Russian patent published in 2008 - IPC C22C38/58 

FIELD: metallurgy; structural weldable steels hardened in air.

SUBSTANCE: proposed method provides for making steels for thermally hardened welded structures, large-sized articles when minimization of sizes and shapes of parts in heat treatment is required. Proposed steel contains the following constituents, mass-%: carbon, 0.10-0.18; silicon, 0.12-0.60; chromium, 2.0-3.0; manganese, 2.0-2.4; nickel, 1.0-2.0; molybdenum, 0.4-0.6; cerium and/or calcium, 0.15 each; vanadium, 0.08-0.12; titanium, lesser than 0.01; niobium, 0.05-0.10; the remainder being iron. After hardening from rolling heat or after austenitization at temperature of 950-1050 C followed by tempering at temperature not higher than 550 C steel has structure of pack martensite.

EFFECT: enhanced strength, toughness, hardenability and weldability.

3 tbl, 1 ex