Super duplex stainless steels combine austenitic and ferritic microstructures and are based on a chromium content of 25%. Many grades meet this basic classification, but the three most widely used are S32550 (Ferralium® 255), S32750 and S32760.
UNS S32550
UNS S32550 equates to Ferralium® 255, DIN 1.4507 and ASTM A182 F61. Ferralium® 255 is the original super duplex stainless steel, invented by Langley Alloys and launched in 1969, giving more than 50 years of service in demanding applications.
Compared with F53 and F55 it delivers increased strength and corrosion performance. Its minimum yield strength as solid bar exceeds 85ksi, where other grades are limited to 80ksi, and it contains up to 2.0% copper, which aids pitting corrosion resistance.
We stock Ferralium® 255-SD50 in sizes from 5/8" to 14" (15.87-355.6mm) diameter solid bar, plus plate up to 3" (76.2mm) thick and pipes, flanges and fittings.
UNS S32750
UNS S32750 equates to DIN 1.4410 and ASTM A182 F53. This is the 25% chromium super duplex originally developed by Alleima and marketed as SAF 2507. We stock S32750 solid bar in sizes from 5/8" to 20" (15.87-508mm) diameter, plate up to 3" (76.2mm) thick, plus pipes in scheduled sizes, fittings and flanges.
UNS S32760
UNS S32760 equates to DIN 1.4501 and ASTM A182 F55. Its origins trace back to the development of Zeron 100 by Platt & Mather in Manchester, UK. It is another 25% chromium super duplex, but with an addition of tungsten. We stock S32760 solid bar in sizes from 5/8" to 20" (15.87-508mm) diameter, plate up to 3" (76.2mm) thick, plus pipes in scheduled sizes, fittings and flanges.