Austenitic stainless steel

Abstract

A stainless steel and its manufacturing method, wherein the steel contains the listed elements but has the following amounts in weight percent: less than 0.03% carbon (C), 0.2 to 0.6% silicon (Si), 1.0 to 2.0% manganese (Mn), 19.0 to 21.0% chromium (Cr), 7.5 to 9.5% nickel (Ni), 0.4 to 1.4% molybdenum (Mo), less than 1.0% copper (Cu), 0.175 to 0.235% nitrogen (N), less than 0.1% titanium (Ti), less than 0.2% niobium (Nb), less than 0.1% vanadium (V), the balance being iron (Fe) and unavoidable impurities, wherein the steel has a proof strength Rp0.2 of 350 to 450 MPa, a tensile strength Rm of 670 to 800 MPa, an elongation at break of more than 47%, and the product of elongation at break and tensile strength (Rm) is greater than 47%. A) Higher than 31490 MPa•%, and the nitrogen (N) content and particle size number meet the following conditions: G + 22.9*N – 14.1 ≤ 0 G + 22.3*N – 10.4 ≥ 0. Austenitic stainless steel and method for manufacturing thereof, wherein the steel comprises listed elements, but in amounts in weight % of less than 0,03 % carbon (C), 0,2 - 0,6 % silicon (Si), 1,0 - 2,0 % manganese (Mn), 19,0 - 21,0 % chromium (Cr), 7,5 - 9,5 % nickel (Ni), 0,4 - 1,4 % molybdenum (Mo), less than 1,0% copper (Cu), 0,175 - 0,235 % nitrogen (N), less than 0,1% titanium (Ti), less than 0.2% niobium (Nb), less than 0.1% vanadium (V), the rest being iron (Fe) and inevitable impurities, wherein the proof strength of the said steel is Rp0,2 350 - 450 MPa, the tensile strength Rm 670 - 800 MPa, the tensile elongation higher than 47%, and the product of tensile elongation and tensile strength (Rm • A) is higher than 31490 MPa•%, and wherein the nitrogen (N) content and the grain size number fulfil the conditions: G + 22.9*N – 14.1 ≤ 0 G + 22.3*N – 10.4 ≥ 0.

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