A kind of acid corrosion-resistant high-strength low-nickel duplex stainless steel and its manufacturing method

Abstract

Provided are acid-corrosion-resistant high-strength low-nickel duplex stainless steel and a manufacturing method thereof. The duplex stainless steel comprises the chemical components by the weight percentage: 0.01-0.06% of C, 0.20-0.50% of Si, 3.0-3.8% of Mn, 21.0-22.0% of Cr, 1.0-1.5% of Ni, 0.15-0.20% of N, 0.40-0.60% of Mo, 2.0-3.0% of Cu, less than or equal to 0.05% of Co, less than or equal to 0.01% of Sn, less than or equal to 0.01% of Pb, less than or equal to 0.5% of the total amount of W, B, Nb, Ti, Co, Al and V, and the balance Fe and inevitable impurities, wherein the ratio of Cu% to Mo% is 5 to 1. The duplex stainless steel has pitting corrosion resistance equivalent to that of S32101 and has acid corrosion resistance superior to that of the S32101, the corrosion resistance in boric acid and other acidic conditions is further improved, the risk of corrosion occurrence is reduced, and the yield strength is increased by 20% or more than that of the conventional S32101; the alloy cost is equivalent to that of the S32101; and ordinary raw materials can be used for smelting products satisfying nuclear power material standards.

Description

Technical field [0001] The present invention relates to duplex stainless steel. Specifically, it relates to an acid-corrosion-resistant, high-strength, low-nickel duplex stainless steel and a manufacturing method thereof. It is particularly suitable for use in the boric acid environment of waste liquid treatment pool panels in nuclear power plants. Background technique [0002] Duplex stainless steel is composed of two phases of ferrite and austenite at room temperature, and the existence of the two-phase structure makes duplex stainless steel have the advantages of both ferrite stainless steel and austenitic stainless steel. Compared with austenitic stainless steel, the strength of duplex stainless steel, especially the yield strength, is significantly improved, which is about twice that of austenitic stainless steel; the resistance to intergranular corrosion, stress corrosion resistance, corrosion fatigue resistance and wear resistance are significantly improved. Compared ...

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Problems solved by technology

Among them, the Japanese patent JP2011069832 and the Chinese CN02145172.9 improve the acid corrosion resistance of the material by adding Sn or Al, rare earth, etc. The product can be used in petrochemical and other industries, but the nuclear power material requires that the Co content is less than 0.05%. Al, Sn, V, Nb, Ti and other elements are strictly controlled below 0.1%, so the above materials cannot be applied

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