AUSTENITIC HIGH-STRENGTH CORROSION-RESISTANT STEEL AND METHOD FOR ITS MELTING Russian patent published in 2012 - IPC C22C38/00 C21C5/52 

FIELD: metallurgy.

SUBSTANCE: austenitic high-strength corrosion-resistant steel has the following components, wt %: 0.04-0.05 carbon; 19.5-20.5 chromium; 4.5-5.5 nickel; 11.5-13.5 manganese; 0.40-0.45 nitrogen; 0.30-0.40 vanadium; 0.2-0.3 niobium; 0.3-0.8 silicon; not more than 0.020 sulfur; not more than 0.030 phosphorus; iron and unavoidable impurities are the rest, when the following conditions are observed: 50·(%C+%N) / %Cr=1.0-1.3; 3·%Nb / (%C+%N) ≤ 2.0. The method of steel melting of the said composition includes charge melting, creation of slag, oxygen lancing, slag skimming, bath deoxidation with ferrosilicon and aluminium lump followed by adding ferroniobium, creation of refining slag, introduction of nitrogen-free ferro-alloys. Then nitrided ferrochrome is introduced to the bath in small portions and the melt is additionally treated in the secondary refining unit and in the vacuum-degassing unit and in the ladle furnace.

EFFECT: invention ensures purity of the melted steel by sulfur and phosphorus, production of a more stable and homogeneous chemical composition of steel.

2 cl, 3 tbl