Specifications
| 1.4410 | X2CrNiMoN 25-7-4 | Z3CND25.07Az |
| Norsok MDS D57 | ASTM A276/A476 | UNS S32750 (Super Duplex 32750) |
| ASME A182 Duplex F53 | CE3MN (Cast grade) | 25Cr |
UNS S32750
Alloy 32750 is a super duplex stainless steel that is supplied in the solution annealed condition. Being a super duplex stainless steel, it combines the favorable characteristics of both austenitic and ferritic grades. Its higher levels of chromium, molybdenum, and nitrogen contribute to a high Pitting Resistance Equivalent number (PREN) of >41, offering superior resistance to pitting and crevice corrosion compared to austenitic and duplex stainless steels across various corrosive environments. Additionally, it has a Critical Pitting Temperature exceeding 50°C. In its annealed state, Alloy 32750 achieves impressive yield strengths of 80ksi (550Mpa), surpassing many austenitic and duplex stainless steel grades. While it cannot be hardened through heat treatment, it can be strengthened via cold working. The alloy also exhibits a low coefficient of thermal expansion and higher heat conductivity when compared to austenitic steels. It is suitable for working temperatures up to 300°C. Notably, Alloy 32750 is listed in NACE MR 0175 for sour service and has gained ASME Approval for Pressure Vessel applications, making it versatile for a wide range of uses.
Chemical Composition Limits
| Â | Cr | Ni | Mo | Co | Nb (+Ta) | Ti | V | W | Cu | C | Mn | N | Si | P | S | Fe | Al |
| Min | 24.50 | 6.00 | 3.00 | – | – | – | – | – | – | – | 0.50 | 0.24 | 0.10 | – | – | – | – |
| Max | 26.00 | 8.00 | 5.00 | – | – | – | – | – | 0.50 | 0.03 | 1.20 | 0.32 | 0.80 | 0.035 | 0.020 | Bal | – |
Mechanical Properties
| 0.2% Proof Stress | 550 N/mm2 | 79.8 ksi |
| Tensile Strength | 800 N/mm2 | 116 ksi |
| Elongation, 5.65√S0 | 25% | – |
| Reduction of area | 45% | – |
| Hardness (Brinell) | <270 | – |
| Impact Strength (Room Temp) | 80J | – |
| Impact Strength (-46oC) | Longitidinal 45J (35J min) | – |
| Transverse 45J (35J min) |
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 |
Key Features
- Excellent corrosion resistance in a wide variety of corrosive chemicals.
- Pitting Resistance Equivalent number (PREN) of >41.
- Outstanding resistance to pitting and crevice. corrosion in seawater and other chloride containing environments.
- Critical Pitting Temperature exceeding 50°C.
- High strength compared to austenitic and 22%Cr duplex stainless steels.
- Excellent ductility and impact strength at both ambient and sub-zero temperatures.
- High resistance to abrasion, erosion and cavitation erosion.
- Excellent resistance to stress corrosion cracking in chloride containing environments.
- Listed in NACE MR 0175 for sour service.
- ASME Approval for Pressure Vessel application.
Applications
- Process industry components in nitric acid, dioxide, polypropylene & PVC production, caustic evaporators.
- Equipment handling organic & fatty acids
- Marine industry and shipbuilding propellers, shafts, rudders, shaft seals, pumps, bolts, fasteners, valves, instrumentation.
- Oil and chemical tankers
- Oil & Gas industry pumps, valves, pipe, vessels, wellhead equipment, subsea equipment.
- Pollution control systems, fans and pumps, wet scrubbers, incinerators, flue gas desulphurisation (FGD).
- Pulp & paper industry components such as black liquor heater tubes, digester blow valves, rotary feed valves, I.D.fans, brownstock washers, precipitators, bleaching components.
- Food Industry applications including sugar cane centrifuges, corn and vegetable processing plant.
- Agrochemicals production such as fertilisers (based on wet phosphoric acid).
- Sewage treatment, seawater cooling, desalination plants.