MARTENSITE-AGEING STEEL AND PRODUCT THEREFROM Russian patent published in 2003 - IPC

FIELD: steelmaking. SUBSTANCE: steel contains following components, wt %: carbon 0.005-0.02, nickel 15-20.0, cobalt 11.5-13.5, molybdenum 3.5-5.0, titanium 0.5-2.0, aluminum 0.05-1.80, boron 0.001-0.005, rare-earth metals 0.001-0.010, iron and inevitable impurities, provided that (Ti+Al)/Co = 0.08+0.25 and Σ(B+rare-earth metals) = 0.005-0.012. Steel may further contain 0.3-3.0% chromium. Products can be made from such steel in the form of stick up to 100 mm in diameter, sheet 1-5 mm thick, and seamless pipes with diameter 24 to 159 mm. EFFECT: improved strength characteristics, cold stamping ability, plasticity after strengthening heat treatment, and polishing ability. 4 cl, 2 tbl, 2 ex