Corrosion of siainbss steels is a known problem in the high pressure section of urea plants. The choice of material is important and the local sen/ice conditions needs to be taken into careful consideration, In 1996 Sandvik and Stamicarbon introduced Safure~R, a duplex stainless steel specially developed for urea service. Now, after more than 20 years of operational experience, it is confirmed that most of the typical corrosion problems that are present in urea plants, can be solved by using Safurex~R. A particularly demanding part of the plant, which often has the highest passive corrosion rates, is the high pressure stripper. Corrosion of Safurex? is hardly detectable in most parts of the high pressure section; except for the heat exchanger tubes in the high pressure stripper, where corrosion rates are comparable with that of austenitic urea grade 25-22-2, which gives room for improvement. Sandvik and Stamicarbon therefore decided to together develop a new premium urea grade with improved corrosion resistance especially for the process conditions which prevails in the heat exchanger tubes of the high pressure stripper.
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