Alloy 31
Designated as UNS N08031 or DIN W.Nr. 1.4562, Alloy 31 is an iron-nickel-chromium-molybdenum alloy with nitrogen and copper additions which has hybridized properties of austenitic super stainless steels and regular nickel alloys. Alloy 31 has exceptional corrosion resistance to alkaline & halide-containing media, sulfuric acid, phosphoric acid, chlorine dioxide media, nitric acid as well as reducing & oxidizing medias. It is widely used in offshore & marine industries, chemical & petrochemical processing, pharmaceutical piping, oil and gas extraction, and ore digestion plants. Especially, Alloy 31 can be used for the fabrication of pressure vessels which may endure a wide temperature-range from cryogenic level to elevated temperatures(-196°C to 550 °C).
Forged gate valves, RF flanged with mating weld neck flanges and extended bonnet. Material: Alloy 31 (UNS N08031).
1. Chemical Composition Requirements
| The Chemical Composition of Alloy 31, % | |
|---|---|
| Nickel | 30.0-32.0 |
| Chromium | 26.0-28.0 |
| Iron | Balance |
| Sulfur | ≤0.010 |
| Si | ≤0.30 |
| Manganese | ≤2.00 |
| Phosphorus | ≤0.020 |
| molybdenum | 6.0-7.0 |
| Copper | 1.0-1.4 |
| Nitrogen | 0.15-0.25 |
| Carbon | ≤0.015 |
2. Physical Properties of Alloy 31
| Density | Melting Range | Permeability | Electrical Resistivity | ||
|---|---|---|---|---|---|
| g/cm3 | lb/in3 | °C | °F | @20°C | µΩ·m |
| 8.05 | 0.290 | 1330-1370 | 2426-2498 | 1.001 | 104 |
3. Mechanical Properties of Alloy 31
Alloy 31 elbows 90° L/R 16″ SCH120, ASTM B366 UNS N08031.
| Tensile Strength, min. | Yield Strength, min. | Elongation, min. | Hardness, min | ||
|---|---|---|---|---|---|
| Mpa | ksi | Mpa | ksi | % | HB |
| 650 | 95 | 277 | 41 | 40 | 220 |
4. Product Forms and Standards
| Product Form | Standard |
|---|---|
| Plate, sheet and strip | ASTM B625 |
| Rod, bars and wire | ASTM B581, B649 |
| Forged flanges & forged fittings | ASTM B564, B462 |
| Welded fittings | ASTM B366 |
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