CORROSION RESISTANT STEEL Russian patent published in 2011 - IPC C22C38/58 C22C38/46 

FIELD: metallurgy.

SUBSTANCE: invention refers to corrosion resistant austenite chromium-nickel steel used at production of bar of high strength, of forged blanks, calibrated rod, wire, strip, sheet, tube, hardware, equipment for gas processing plants and oil-field construction with high contents of hydrogen sulphide, carbon dioxide and chlorides, and also for operation in sea water. Steel contains carbon, silicon, manganese, chromium, nickel, molybdenum, vanadium, nitrogen, cerium, calcium and iron at the following ratio of components, wt %: carbon 0.01 - 0.10, silicon 0.05 - 2.0, manganese 0.1 - 3.0, chromium 17.0 - 26.0, nickel 11.0 - 24.5, molybdenum 1.0 - 5.0, nitrogen 0.05 - 0.40, vanadium 0.01 - 0.25, cerium 0.01 - 0.05, calcium 0.001 - 0.150. Contents of sulphides in steel do not exceed 2 points, while line and pointed nitrides and carbonitrides - not more, than 3 points for each kind. The following ratios are maintained for steel components: (%V+%Ce+%Ca)/(%C+%N)=0.25÷0.65, 0.5<(%Ni+0.5%Mn)/(%Cr+%Mo+1.5%Si+%V)<0.9 and %Ni+16(%C+%N)-(%Cr+1.5%Mo-20)²/12=14÷24.

EFFECT: increased resistance to pitting corrosion in hydrogen sulphide containing mediums and chlorides, raised mechanical characteristics at maintaining resistance to hydrogen sulphide cracking, inter-crystal corrosion and stable austenite non-magnetic structure with magnetic permeability maximum 1.00 g/e.