ELEVATED-HARDENABILITY THERMOSTRENGHTENABLE STEEL FOR COLD DIE FORGING Russian patent published in 2004 - IPC

FIELD: steelmaking. SUBSTANCE: invention relates to developing structural steel appropriate for manufacturing profiled thermo-improved parts. Steel is composed of, wt %: carbon 0.17-0.25, manganese 0.90-1.40, silicon 0.01-0.17, sulfur 0.005- 0.020, chromium 0.01-0.25, vanadium 0.01-0,07, nickel 0.01-0.10, copper 0.01-0.10, molybdenum 0.01-0.10, titanium 0.01-0.04, boron 0.0005-0.0050, aluminum 0.02-0.06, nitrogen 0.005-0.015, calcium 0.001-0.010, and iron - the balance, provided that 22 ≤ 12/C - Mn/0.55 ≤ 47, (N/10Ti + Al) ≤ 0.039. and (10B - 0.01C)/N ≥ 1.80. EFFECT: achieved throughout hardenability of high-quality rolled metal from claimed steel with diameter up to 30 mm. 2 tbl, 10 ex