UR52N+ (UNS S32550) is a super duplex stainless steel with 25% chrome and a PREN value higher than 40. The molybdenum and nitrogen additions have been optimized to obtain the best corrosion resistance properties. High nitrogen content improves the stability of the microstructure of the metal particularly in the heat-affected zone (HAZ). The corrosion resistance of UR52N+ is much better than regular 904L material and is roughly equal to the six molybdenum super austenitic steel alloys. Copper additions increase the corrosion resistance properties, particularly in sulfuric acid media.

UR52N+ performs particularly well in sulphuric and phosphoric acid solutions, even in the presence of chlorides. The microstructure provides high mechanical properties, which explains why the alloy performs well in abrasion-corrosion conditions such as agitators, screws, and rakes.

UR52N+ is often used in pollution control equipment where mixed acids are often associated with chlorides. With high chromium, molybdenum and copper additions, UR52N+ behaves very well in scrubber systems. In the pulp and paper industry, UR52N+ is used in the most severe conditions encountered such as digesters (resistant to hot wall problems), chip pre-steaming vessels and in some bleaching equipment.

UR52N+ has excellent resistance to crevice corrosion, pitting and chloride induced stress corrosion cracking. It has a high strength to weight ratio due to its high mechanical properties. These high mechanical properties provide good resistance to erosion and abrasion. UR52N+ has over twice the yield strength of austenitic stainless steels. This allows customers to reduce the wall thickness on equipment and save costs. UR52N+ also has high fatigue strength in saltwater applications.

UR52N+ is resistant to stress corrosion cracking caused by the presence of chlorides in the media. The minimum PREN value of 40 also explains why the alloy is highly resistant to pitting corrosion and crevice corrosion. The alloy behaves much better than 904L and is, for pitting resistance, nearly equivalent to 6 MO super austenitic grades of stainless steels. In some cases, the crevice corrosion resistance is slightly higher than 6 MO alloys due to the 25% chrome additions.

In summary, UR52N+ alloy is an effective choice for products used in corrosion environments such as sulphuric acid or phosphoric acid, especially if chlorides are present. It provides an excellent level of corrosion resistance along with cost saving design characteristics. If can provide another choice to your corrosion problems.

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