CORROSION-RESISTANT AUSTENITIC TRIP-STEEL FOR COLD PLASTIC DEFORMATION AND ARTICLE PRODUCED FROM SUCH STEEL Russian patent published in 2003 - IPC

FIELD: metallurgy, mechanical engineering. SUBSTANCE: corrosion-resistant austenitic trip-steel comprises, wt%: hydrogen 0.20-0.25; silicon 0.25-0.50; manganese 0.70-0.85; chromium 14.5-16.0; nickel 4.8-5.8; molybdenum 2.7-3.0; nitrogen 0.10-0.13; titanium 0.012-0.020; aluminum 0.05-0.05; unavoidable admixtures including sulfur about 0.015; phosphor about 0.015; oxygen about 0.003; iron the balance. Chromium, hydrogen, nickel and molybdenum content makes the following dependence: wt% Cr=30-(16-17)%C-(1.4-1.5)%Ni-(1.2-1.3)%Mo, titanium to hydrogen ratio is (0,5÷0,8)•10^-2, and grain fineness number is at least 7 according to State Standard GOST 5639. Corrosion-resistant austentic trip-steel additionally comprises 0.03-0.10 wt% of cerium provided the ratio be kept. Amount of α-phase after melting is no more than 10 wt%. Steel of such composition may be also used in aviation for manufacture of steel strips, for example, aircraft parts of essential importance, in particular, torsion bars for 0.3 mm thick helicopter rotors, in manufacture of compressor valve plates with the thickness of up to 1 mm and other parts to be heavily loaded during operation under dynamic force conditions. Steel and articles produced from such steel have good corrosion resistance and cold plastic deformation capacity. EFFECT: increased strength, ductility and corrosion fatigue life of steel and parts fabricated from it. 4 cl, 3 ex