UNSTABILIZED AUSTENITIC STEEL CORROSION-RESISTANT IN LIQUID LEAD AND STEAM WATER MEDIUM Russian patent published in 2023 - IPC C22C38/58 C22C38/54 C22C38/46 C22C38/44 

FIELD: metallurgy.

SUBSTANCE: invention is related to corrosion-resistant austenitic steels with a high content of silicon for use in nuclear power engineering in manufacturing of heat exchange equipment operating at high temperature in contact with a steam-water medium and heavy liquid metal coolants, in particular, for manufacturing of heat exchange tubes for steam generators of nuclear power plants operating at temperatures of 350-550°C. Steel contains, in wt.%: carbon 0.005-0.04, silicon 1.6-2.5, manganese 0.5-2.0, chromium 18.0-23.0, nickel 10.0-17, 5, molybdenum 1.8-4.0, nitrogen 0.10-0.22, vanadium 0.01-0.15, tungsten 0.01-1.00, boron 0.0005-0.008, barium 0.005-0, 01, calcium from more than 0.02 to 0.15, cerium 0.005-0.01, iron and inevitable impurities being the rest. The contents of steel components satisfy the following relationships: (1.5[Cr] + 1.2[Mn] + 1.1[Mo] + 2.4[V] + 0.5[W] - 1.7[Si] - 1.2[Ni] - 2.3[B]) / ([N] + [C]) ≥ 65 and [Cr] + 3.3[Mo] + 0.5[Si] + 20[C] + 20[N] - 0, 5[Mn] - 0.25[Ni] ≥ 25.

EFFECT: eliminates the tendency to intergranular corrosion, thermal aging at a temperature of 350°C, local destruction of the near-weld zone and knife corrosion while maintaining resistance to corrosion cracking, pitting and liquid metal corrosion, respectively, in chloride-containing media and lead without reducing the level of mechanical properties at 350-550°C.

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