UNS N08031(Alloy 31)
Generic Name & Other Designation
Nicrofer® 3127 hMo, Alloy 31, W.Nr. 1.4562, ISO 1.4562
Product Overview
UNS N08031 (Alloy 31) is an advanced super-austenitic nickel-iron-chromium-molybdenum alloy fortified with nitrogen and copper. Developed to bridge the economic gap between standard 6% Mo super-austenitics and high-cost nickel alloys, UNS N08031 exhibits incredible resistance to acidic media contaminated with halogenides.
It demonstrates outstanding longevity in sulfuric acid concentrations ranging from low to high density, acidic waste streams, and saline cooling water installations.
Key Highlights
✅ High PREN Value (≥ 48): Ultra-high Pitting Resistance Equivalent Number ensures extreme crevice corrosion immunity.
✅ Phosphoric Acid Superiority: Designed for high-temperature wet-process phosphoric acid concentration lines.
✅ Nitrogen Strengthened: Nitrogen addition increases mechanical yield strength while preserving ductility.
✅ Acid Slurry Resistance: Superior resistance to erosive-corrosive slurries containing particulate matter.
Chemical Composition & Physical Properties
1. Chemical Composition (wt%)
Element | Ni | Cr | Fe | Mo | Cu | N | C | Mn | Si | P | S |
Min (%) | 30.0 | 26.0 | Bal. | 6.0 | 1.0 | 0.15 | — | — | — | — | — |
Max (%) | 32.0 | 28.0 | (~38.0) | 7.0 | 1.4 | 0.25 | 0.015 | 2.0 | 0.50 | 0.020 | 0.010 |
(Note: Ultra-low carbon content C ≤ 0.015% prevents intergranular precipitation during thermal cycles.)
2. Physical & Mechanical Properties
Parameter | Value / Standard (Solution Annealed Condition) |
Density | 8.10 g/cm³ (0.293 lb/in³) |
Melting Range | 1335°C – 1380°C (2435°F – 2516°F) |
Tensile Strength (Rm) | ≥ 650 MPa (94 ksi) |
Yield Strength (0.2%, Rp0.2) | ≥ 280 MPa (40 ksi) |
Elongation (A5) | ≥ 40% |
Hardness Range | ≤ 220 HBW |
Available Forms
Plates & Sheets: Quenched and annealed heavy plates, thin coils.
Tubular Products: Heat exchanger tubes, seamless transport lines.
Bar & Rod: Machined round bars, valve shafts, pump shafts.
Pipe Components: Weld necks, elbows, concentric reducers.
Typical Application Scenarios
Fertilizer Industry: Phosphoric acid evaporators, heat exchangers, acid recirculating lines.
Mining & Hydrometallurgy: Ore leach autoclaves, solvent extraction units.
Chemical Recycling: Waste acid concentration and recovery plants.
Quality Assurance & Testing
Pitting corrosion test per ASTM G48 Method A up to elevated temperatures.
Grain boundary intergranular corrosion evaluation.
Fully compliant with ISO 9001 quality management guidelines and EN 10204 3.1.
Supplier Information (BELNADE)
Delivered globally by BELNADE, UNS N08031 products are offered in a range of mill forms with complete dimensional and metallurgical testing. BELNADE supports complex engineering requirements with fast turnaround times.
Get in Touch with BELNADE for Quotes and Technical Inquiries
📧 Email: info@belnade-material.com
🌐 Website: www.belnade-material.com
💬 Mobile/ WhatsApp: +86 158-0040-6687