UNA S32760 F55

Alloy 32760 (Plate) (UNS S32760)


Alloy 32760 is a super duplex stainless steel supplied in the hot worked and solution annealed condition. As a super duplex stainless steel, it combines the desirable aspects of both austenitic and ferritic grades. The higher chromium, molybdenum and nitrogen contents result in a Pitting Resistance Equivalent number (PREN) of >40, providing pitting and crevice corrosion resistance superior to austenitic and duplex stainless steels in almost all corrosive media, and a Critical Pitting Temperature exceeding 50°C   nb.versions of the PREN formula also include W as a positive influence on overall pitting resistance.

It provides higher strength than both austenitic and 22% Cr duplex stainless steels, and is listed in NACE MR 0175 for sour service and ASME for pressure vessel applications.

Key Features:

1.Excellent corrosion resistance in a wide variety of corrosive chemicals

2.Pitting Resistance Equivalent number (PREN) of >40

3.Outstanding resistance to pitting and crevice corrosion in seawater and other chloride containing environments

4.Critical Pitting Temperature exceeding 50°C

5.High strength compared to austenitic and 22%Cr duplex stainless steels

6.Excellent ductility and impact strength at both ambient and sub-zero temperatures

7.High resistance to abrasion, erosion and cavitation erosion

8.Excellent resistance to stress corrosion cracking in chloride containing environments

9.Listed in NACE MR 0175 for sour service

10.ASME Approval for Pressure Vessel application


1.Process industry components in nitric acid, dioxide, polypropylene & PVC production, caustic

2.Equipment handling organic & fatty acids

3.Marine industry and shipbuilding propellers, shafts, rudders, shaft seals, pumps, bolts, fasteners, valves, instrumentation

4.Oil and chemical tankers

5.Oil & Gas industry pumps, valves, pipe, vessels, wellhead equipment, subsea equipment

6.Pollution control systems, fans and pumps, wet scrubbers, incinerators, flue gas desulphurisation (FGD)

7.Pulp & paper industry components such as black liquor heater tubes, digester blow valves, rotary feed valves, I.D.fans, brownstock washers, precipitators, bleaching components

8.Food Industry applications including sugar cane centrifuges, corn and vegetable processing plant

9.Agrochemicals production such as fertilisers (based on wet phosphoric acid)

10.Sewage treatment, seawater cooling, desalination plants

Chemical Composition:






Nb (+Ta)













Min 24.00 6.00 3.00         0.50 0.50     0.20          
Max 26.00 8.00 4.00         1.00 1.00 0.025 1.00 0.30 1.00 0.025 0.005 Bal 0.01

Mechanical Properties:

0.2% Proof Stress 550 N/mm2 79.8 ksi
Tensile Strength 750 N/mm2 108.8 ksi
Elongation, 5.65√S0 25%  
Reduction of area 45%  
Hardness (Brinell) 270HBN max  
Impact Strength (Room Temp) 80J 59 lb.ft
Impact Strength (-46oC) 60J av (45J min) 44 lb.ft av (33 lb.ft min)


1.Testing shall be carried out in accordance with ASTM A370 or EN ISO 6892-1 (tensile), EN ISO 6506-1 (hardness)

2.Minimum properties quoted (tested at room temperature in a longitudinal direction

3.Testing performed on each melt of material per heat treatment batch

4.Hardness shall be in accordance with NACE MR 1075 with a maximum HRC of 28

5.ASTM G48A corrosion test (at 50degC) No pitting and < 3.0g/m2 weight loss (ASTM specification <4.0g/m2)

6.Ferrite content 35-55%

7.Microstructure certified free from grain boundary carbides, sigma, chi and laves phases

Physical Properties:

Density (Kg/m3) 7810
Magnetic Permeability (20°C) 33
Young’s Modulus (kN/mm2) 199
Specific Electrical Resistance, 20°C (µΩ.m) 0.8
Mean coefficient of thermal expansion, 20-300°C (m/m/oC) 11.1 x 10-6
Specific Heat, 20°C (J/kg.K) 475
Thermal conductivity, 20°C (W/m.K) 14.2
Fracture Toughness, kQ (MPa/m2) 98