Nickel and nickel alloys · Alloy 31 / Nicrofer 3127 hMo / UNS N08031 / 1.4562
Alloy 31 (1.4562 / UNS N08031): Engineering Handbook
Engineering Specifications and Standards for Alloy 31
| Product Form | Alloy Name | Main Specifications | Analogues | ||
|---|---|---|---|---|---|
| Sheet, Plate, Bar, Wire, Rod, Strip | Alloy 31, Nicrofer 3127 hMo, VDM Alloy 31, UNS N08031 | ASTM: B 564, B 581, B 625, B 649 | ASME: SB 581, SB 625, SB 649 | W.Nr. 1.4562 (X1NiCrMoCu32-28-7) | ISO: NACE MR0175/ISO 15156:2003 |
Alloy 31 (UNS N08031) is an austenitic iron-nickel alloy, alloyed with chromium, molybdenum, and copper, with a precise addition of nitrogen. This composition provides outstanding resistance to general and localized corrosion in extreme chemical environments, including phosphoric and sulfuric acids, as well as in chloride-rich media.
Chemical Composition of Alloy 31 (UNS N08031), %
| Ni | 30.0-32.0 |
|---|---|
| S | <0.010 |
| C | <0.015 |
| P | <0.020 |
| N | 0.15-0.25 |
| Si | <0.3 |
| Cu | 1.0-1.4 |
| Mn | <2.0 |
| Mo | 6.0-7.0 |
| Cr | 26.0-28.0 |
| Fe | Balance |
Mechanical Properties of Alloy 31 at Elevated Temperatures
| Temperature | Yield Strength (MPa) | Tensile Strength (MPa) |
|---|---|---|
| 20°C | 280 | 650 |
| 100°C | 210 | 630 |
| 200°C | 180 | 580 |
| 300°C | 165 | 530 |
| 400°C | 150 | 500 |
| 500°C | 135 | 470 |
| 550°C | 125 | 450 |
The presented mechanical property values correspond to the material's as-supplied condition after heat treatment (solution annealing at 1120-1160°C and water quenching) and are minimum guaranteed values.
Physical-Thermal Properties of Alloy 31
Nominal material density at 20°C: 8.05 g/cm³.
| Temperature (°C) | 20 | 300 | 600 |
|---|---|---|---|
| Thermal Conductivity (W/m*°C) | 11.7 | 16.8 | 21.9 |
| Electrical Resistivity (µohm*cm) | 104 | 113 | 120 |
| Modulus of Elasticity (GPa) | 198 | 176 | 158 |
Corrosion Resistance
Alloy 31 demonstrates exceptional corrosion resistance in a wide range of aggressive media. It is recommended for use in contact with sulfuric acid (at concentrations up to 60% and temperatures up to 100°C), phosphoric acid of any concentration, and in halide-containing media, where it outperforms many standard stainless steels. Thanks to its high PREN (Pitting Resistance Equivalent Number) value, the alloy is resistant to pitting and crevice corrosion in chloride solutions. It also effectively resists stress corrosion cracking.
Welding
Welding of Alloy 31 is performed using all standard methods (TIG, MIG, MMA). To ensure equal strength and corrosion resistance of the weld joint at the level of the base metal, EV Group China recommends using welding consumables with an increased content of alloying elements. Optimal choices are filler rods and wire of Alloy 59 (W.Nr. 2.4607 / ERNiCrMo-13) or Alloy C-276 (W.Nr. 2.4819 / ERNiCrMo-4).
Key Performance Advantages of Alloy 31
- Exceptional resistance to pitting (PREN ≥ 48) and crevice corrosion in chloride and acidic environments.
- Full compliance with NACE MR0175/ISO 15156 standards for application in sour gas/oil environments in the oil and gas industry.
- ASME code certification for pressure vessels, approved for operation at temperatures up to 427°C.
Engineering Applications
- Components for Flue Gas Desulfurization (FGD) systems, including absorbers, pipelines, and mist eliminators.
- Heat exchangers, reactors, and evaporators in wet-process phosphoric acid production.
- Pipeline systems and heat exchange equipment using seawater or brackish water as a cooling medium.
- Equipment for extraction, processing, and transportation of sour gas/oil.
- Bleaching plants in the pulp and paper industry operating with chlorine dioxide.