S32760 is a super duplex stainless steel, standardised under UNS S32760 (ASTM F55, DIN 1.4501). It is the specification equivalent of the trademarked alloy Zeron 100, and one of three super duplex grades we hold as stock.

Where S32760 came from

The origins of Alloy 32760 trace back to Zeron 100, developed by Mather & Platt, a Manchester foundry that supplied castings for a range of applications but developed this alloy primarily for its centrifugal pumps for the oil and gas industry.

The Zeron trademark was registered in 1980, some 13 years after Langley Alloys registered the trademark Ferralium®, associated with the very first super duplex stainless steel. The Zeron 100 patent was published in 1984, 15 years after the respective patent for Ferralium® 255. Both alloys use a 25% chromium content as their reference point, now known as super duplex. Zeron 100 foregoes a significant portion of the copper addition that gives Ferralium® its resistance to select acids, replacing it with tungsten additions.

Ownership of Zeron 100 passed to Weir Materials, and subsequently to the current trademark owner, Rolled Alloys Inc. The original Mather & Platt foundry site was acquired by the Westley Group but is no longer operational.

As with many trademarked alloys, a close approximation was accepted into technical standards such as ASTM A276 and A479 under the UNS designation S32760, and as F55 in ASTM A182.

How we stock S32760

S32760 is one of three super duplex stainless steels we stock, alongside our own Ferralium® 255 and S32750 / SAF2507. We hold it as barstock in the UK and Houston, in sizes from 1/2" (12.7mm) to 16" (406.4mm) diameter, plus as plate at our USA warehouse from 3/16" (4.76mm) to 2 1/2" (63.5mm) thickness.

Grade designations

Duplex stainless steels

  • Sanmac 2205 - Alloy 2205, UNS S32205, DIN 1.4462, F60, UNS S31803, F51

Super duplex stainless steels

  • Ferralium® 255-SD50 - Alloy 255, UNS S32550, DIN 1.4507, F61
  • SAF2507 - Alloy 32750, UNS S32750, DIN 1.4410, F53
  • S32760 - Alloy 32760, UNS S32760, DIN 1.4501, F55, Zeron 100
Grade UNS DIN ASTM F
2205 (Sanmac 2205) S31803 / S32205 1.4462 F51 / F60
Ferralium® 255-SD50 S32550 1.4507 F61
SAF2507 S32750 1.4410 F53
S32760 (Zeron 100) S32760 1.4501 F55