Duplex Steels 2205 • S31803/S32205 • 1.4462

2205 Duplex Stainless Steel Tubes. A widely used duplex steel combining high strength and corrosion resistance in various organic acids, anorganic acids, aggressive coolingwaters and hydrous H2 S/NaCl mixtures. With a near equal mix of austenite and ferrite, they give yield strength 30% higher and tensile strengths marginally higher than comparable nitrogen-containing austenitics. High resistance to general corrosion and specifically to pitting and crevice corrosion. Their resistance to stress-corrosion cracking in neutral chlorides is superior to that of the austenites. In high chloride acidic or moderately sour environments where hydrogen or sulphide stress cracking is more likely, higher alloyed austenitics need also to be considered. Impact values are high and transition temperatures of base materials vary around – 50°C. However, the proportion and orientation of ferrite in welds and base materials may significantly affect toughness at subzero temperatures. Exposure to moderate and high temperatures and less rapid cooling may cause embrittlement.