Grade UR52N+ is a registered trade name of the Usinor group, produced in a range of products. UR52N+ is designated UNS S32520 for plate (in ASTM A240M) but retains the older designation UNS S32550 for bar (in ASTM A276M). It is anticipated that in the future UR52N+ bar will be re-classified as S32520.

UR52N+ is one of a group of "super duplex" grades, combining high strength with exceptional corrosion resistance. Like other duplex (ferritic/austenitic) grades the super duplex grades are not suitable for high or low temperature service. UR52N+ is not recommended for temperatures below -50°C or above +270°C, because of reduced toughness outside this range.

The addition of copper to this grade gives it greatly improved resistance to strong reducing acids, particularly sulphuric acid. UR52N+ is also very highly resistant to pitting / crevice corrosion in high chloride environments. Its duplex structure also results in excellent resistance to stress corrosion cracking.
Key Properties

These properties are specified for flat rolled product (plate, sheet and coil) in ASTM A240M, Grade S32520. Similar but not necessarily identical properties are specified for other products such as pipe and bar in their respective specifications.