Corrosion attack by seawater and sour gas, high mechanical stresses and flexing due to currents and waves are encountered by umbilicals which connect a floating vessel or an oil platform with a satellite oil well. Materials used for umbilicals are normally selected with regard to their combination of high mechanical values and local corrosion resistance. Additionally resistance to stress corrosion cracking (SCC) and sulphide stress cracking (SSC) is required. They include 300 series stainless steels, nickel alloys, duplex and super duplex stainless steels and zinc coated carbon steels. To confirm its potential for subsea application, the new chromium-based austenitic material "Alloy 33" (with the nominal composition 33 % Cr, 32 Fe, 31 Ni, 1.6 Mo, 0.6 Cu and 0.4 N) was tested
under relevant conditions. The corrosion results obtained are comparable to those obtained on superduplex stainless steels. However, due to its superior toughness even in the cold worked condition, Alloy 33 provides an additional safety margin. Easy manufacturing of longitudinally welded tubes in combination with the high corrosion resistance make this alloy an economical and reliable material solution for umbilicals. Keywords: Alloy 33, 1.4591, local corrosion resistance, stress corrosion cracking, chloride-containing solutions, seawater, umbilicals.