DUPLEX STAINLESS STEEL FOR PRODUCTION OF SHUTOFF AND CONTROL VALVES Russian patent published in 2019 - IPC C22C38/48 

FIELD: metallurgy.

SUBSTANCE: invention relates to duplex stainless steel used for production of shutoff and control valves of corrosion-active gas media with high content of hydrogen sulphide. Steel contains components at the following ratio, wt. %: carbon 0.01–0.04, silicon 0.3–0.5, manganese 0.9–1.2, chromium 22.5–24.0, nickel 5.8 –7.0, molybdenum 3.5–4.8, nitrogen 0.16–0.25, copper 3.0–3.3, niobium 0.27–0.37, cerium and/or lanthanum 0.001–0.004, sulfur ≤0.004, phosphorus ≤0.004, aluminum 0.01–0.02, calcium 0.001–0.004, yttrium ≤0.005, iron is the rest. After electroslag remelting, it has structure containing 50–60 vol. % of ferrite, inside which ferritic grains of which there are nitrides and nitrite carbonitrides of size ≤300 nm.

EFFECT: higher visco-plastic characteristics of steel in combination with high corrosion resistance and resistance to corrosion cracking in aggressive gas mediums of hydrogen sulphide.

1 cl, 2 tbl, 2 dwg