Alloy 31 Plates | UNS N08031 Super Austenitic Plates for Chemical, Oil & Gas, Marine, Pharma & Power
Table of Contents:
A coastal acid‑production and sour‑gas treatment complex had already cycled through 316L, 904L and Alloy 28 plates in its mixed sulfuric, phosphoric and chloride‑bearing loops, yet every turnaround the inspection maps lit up with fresh pitting around welds, accelerated wall‑loss in hot acid headers and grooving in the sour‑gas contactor internals. When the integrity and procurement teams rebuilt the most punished absorber shells, tube sheets and manifolds in Alloy 31 Plates (UNS N08031, EN 1.4562), they switched to a super‑austenitic alloy with about 30–32% nickel, 26–28% chromium, 6–7% molybdenum and 0.15–0.25% nitrogen whose data show yield strength above 280 MPa, tensile strength above 650 MPa, elongation above 40%, together with excellent resistance to sulfuric and phosphoric acids and high pitting resistance; inspection reports over successive campaigns recorded stable thickness readings where previous plates had repeatedly failed.
Alloy 31, often marketed under trade names such as Nicrofer 3127 hMo, is an advanced iron–nickel–chromium–molybdenum super‑austenitic stainless steel with nitrogen and copper additions designed to close the performance gap between high‑alloy stainless steels and fully nickel‑base alloys. Its chemistry is optimised to deliver outstanding resistance in alkaline and acidic halide media, excellent resistance to sulfuric acid across a broad range of concentrations and temperatures up to around 80 °C and strong resistance to corrosion and erosion in phosphoric acid production, while also performing well in reducing and oxidising media and in boiling azeotropic nitric acid.
For procurement heads, corrosion and mechanical engineers, fabricators, OEMs and hardware or industrial supply stores serving chemical, oil & gas, marine, pharma and power‑generation customers, Alloy 31 plates provide a strategic upgrade where 316L, 904L, Alloy 20 or Alloy 28 are marginal but full nickel‑base alloys appear cost‑prohibitive. Sources note that Alloy 31 typically achieves a pitting resistance equivalent number (PREN) of at least about 48, giving very high resistance to pitting and crevice corrosion in chloride‑containing environments, while test data in sulfuric and phosphoric acid and H₂S‑bearing systems show corrosion rates low enough for long life at conditions that rapidly attack conventional austenitic stainless steels.
Aurico Alloys LLP can support these demands as an affordable, authentic Alloy 31 Plates supplier, manufacturer and stockist in India with exports abroad, offering plate aligned with UNS N08031 / EN 1.4562 chemistry and ASTM B625 or related standards with EN 10204 certification to EPC, OEM and MRO users in process, marine and power markets.
High-quality Alloy 31 Plates ready for industrial use.
Specification Overview
| Supplier & Role | Aurico Alloys LLP – Alloy 31 Plates supplier, stockist, exporter in India to abroad |
|---|---|
| Alloy Description | Iron–nickel–chromium–molybdenum super‑austenitic stainless steel with nitrogen and copper, positioned between high‑alloy stainless and nickel alloys |
| UNS / EN / Werkstoff | UNS N08031, EN 1.4562 |
| Main Plate Standards | Commonly supplied under ASTM B625 / ASME SB‑625 for plate, sheet and strip, alongside producer data sheets for Nicrofer 3127 hMo / Alloy 31 |
| Thickness Range | 4.75 mm – 150 mm |
| Corrosion Focus | Outstanding resistance in sulfuric acid (including contaminated acid up to around 80 °C), excellent resistance in phosphoric acid and halide‑containing media, high pitting resistance and good resistance in boiling azeotropic nitric acid |
UNS & Equivalent Grades
| Property | Value |
|---|---|
| UNS number | N08031 |
| Werkstoff / EN number | 1.4562 |
| EN designation | X1NiCrMoCu32-28-7 |
| Density | 8.05 g/cm3 |
| Melting range | 1330-1370 °C |
| Modulus of elasticity (20 °C) | 198 GPa |
| Thermal conductivity (20 °C) | 11.7 W/m·K |
| Electrical resistivity (20 °C) | 104 µΩ·cm |
| Coefficient of expansion (100 °C) | 14.3 µm/m·°C |
| Magnetic permeability (relative - at 20 °C) | 1.001 |
| Plate, sheet and strip specification | ASTM B625 |
Identifiers and physical constants for Alloy 31. A dash means no such designation is published for this grade.
Stock & Product Availability
As an Alloy 31 Plates stockist, Aurico Alloys LLP can supply plate and sheet thicknesses suitable for absorber and scrubber shells, tube sheets, channel covers, manifolds, seawater‑cooled equipment and structural plates in chemical, oil & gas, marine, pharma and power‑generation plants, within the size ranges typically associated with ASTM B625 and producer plate data. Plates are generally delivered in solution‑annealed and quenched condition for maximum corrosion resistance and impact toughness, and services such as cut‑to‑size, contour cutting and weld‑prep edge machining help fabricators and OEMs reduce machining and fit‑up time while maintaining full heat‑number and batch traceability.
Chemical Composition
| Element | Min (%) | Max (%) |
|---|---|---|
| Nickel (Ni) | 30.0 | 32.0 |
| Chromium (Cr) | 26.0 | 28.0 |
| Iron (Fe) | — | Balance |
| Sulfur (S) | — | 0.010 |
| Silicon (Si) | — | 0.3 |
| Manganese (Mn) | — | 2.0 |
| Phosphorus (P) | — | 0.020 |
| Molybdenum (Mo) | 6.0 | 7.0 |
| Copper (Cu) | 1.0 | 1.4 |
| Nitrogen (N) | 0.15 | 0.25 |
| Carbon (C) | — | 0.015 |
Composition limits for Alloy 31. These are specification limits for the grade, not measured values for a lot; the mill test certificate supplied with your order states the actual analysis.
Mechanical & Physical Properties
| Property (Room Temperature, Solution-Annealed Plate) | Typical Value – Alloy 31 |
|---|---|
| Ultimate Tensile Strength | ≥650 MPa according to multiple plate datasheets |
| Yield Strength (0.2% offset) | ≥275–280 MPa in 20 °C plate data |
| Elongation | ≥40% in standard tensile tests, with some sources reporting about 45% elongation at break for plate |
| Impact Toughness | Reported ISO V‑notch impact values of at least about 185 J/cm² at 20 °C and 140 J/cm² at –196 °C |
| Modulus of Elasticity | ≈198–210 GPa, similar to other austenitic stainless steels |
| Thermal Conductivity (20 °C) | ≈11.7 W/(m·K) |
| Pitting Resistance (PREN) | Described as typically ≥ about 48, reflecting very high resistance to pitting in chloride environments |
Applications & Benefits
- Chemical & Oil & Gas: Alloy 31 plates are used in sulfuric‑acid coolers, phosphoric‑acid heat exchangers, reactor and scrubber shells, fertiliser equipment and sour‑gas manifolds where tests show excellent resistance to sulfuric acid, very good performance in phosphoric acid and strong resistance to SCC and localised attack in chloride‑containing and H₂S‑bearing environments.
- Marine & Power Generation: In seawater‑cooled condensers, FGD systems, coastal power‑plant equipment and marine chemical‑dosing systems, UNS N08031 / 1.4562 plates offer very high pitting and crevice‑corrosion resistance in chloride‑rich media and good strength retention up to several hundred degrees Celsius, supporting lighter and longer‑lasting designs than many conventional stainless steels.
- Pharma & High‑Purity Plant: Alloy 31 can be selected for high‑value intermediates, waste‑treatment and scrubber systems where mixed acids, halides and elevated temperatures are present, but low contamination, good weldability and consistent surface finish are required under strict quality regimes.
FAQ & Search Trends
Global Export Destinations
We ship worldwide from Mumbai. See every destination we export to on our export markets page.
Domestic Supply Network
We deliver across India from our Mumbai stockyard. See every city we supply on our supply locations page.
Conclusion
Alloy 31 Plates from Aurico Alloys LLP, supplied to UNS N08031 / EN 1.4562 chemistry limits and ASTM B625 mechanical requirements, give chemical, oil & gas, marine, pharma and power‑generation users a super‑austenitic plate option that combines high strength, very high pitting resistance and excellent performance in sulfuric, phosphoric and mixed chloride media at elevated temperatures are your most critical sour‑gas, acid and seawater‑exposed assets still relying on lower‑alloy materials instead of optimised Alloy 31 plates?