STRUCTURAL STEEL Russian patent published in 2001 - IPC

FIELD: ferrous metallurgy, more particularly manufacture of structures serviceable at low temperatures, e.g. pipelines, sea stationary platforms, load-carrying structures of floating drilling rigs, reservoirs, building structures and machine components. SUBSTANCE: structural steel comprises, wt %: carbon, 0.08-0.22; silicon, 0.20-0.65; manganese, 1.25-2.20; titanium, 0.01-0.03; aluminium, 0.01-0.05; niobium, 0.01-0.23; boron, 0.001-0.005; zirconium, 0.01-0.05; nitrogen, 0.01-0.015; copper, 0.25-0.55; calcium 0.0015-0.055; yttrium, 0.0001-0.055; selenium, 0.00025-0.07; barium, 0.01-0.035; hafnium, 0.035-0.065; and iron, the balance. Steel comprises limited content of impurities, wt %: sulfur, up to 0.035 and phosphorus, up to 0.035. Higher resistance to fragile, destruction, higher plasticity with respect to thickness of rolled products, improved workability and weldability. EFFECT: improved properties of the structural steel. 2 cl, 1 ex, 2 tbl