Alloy 400
Alloy 400 is a nickel-copper alloy known for its excellent corrosion resistance and ease of fabrication. It can be formed and fabricated without additional heat treatments, while maintaining good mechanical properties at low temperatures. It resists various acids, including hydrofluoric acid, sulfuric acid, and hydrochloric acid under reducing conditions. Alloy 400 is widely used in marine engineering, chemical processing, and other industries for applications such as valves, pumps, fittings, and heat exchangers.
Chemical Composition Limits
| Â | Cr | Ni | Mo | Co | Nb (+Ta) | Ti | V | W | Cu | C | Mn | N | Si | P | S | Fe | Al |
| Min | – | 63.00 | – | – | – | – | – | – | 28.00 | – | – | – | – | – | – | – | – |
| Max | – | – | – | – | – | – | – | – | 34.00 | 0.30 | 2.00 | – | 0.50 | – | 0.024 | 2.50 | – |
Physical Properties​
| Density (Kg/m3) | 8830 |
| Magnetic Permeability (20°C) | Could show magnetism as Curie temperature is close to room temperature |
| Young’s Modulus (kN/mm2) | 179 |
| Specific Electrical Resistance, 20°C (µΩ-m) | 0.51 |
| Mean coefficient of thermal expansion, 20-100°C (m/m/degC) | 14.1 x 10-6 |
| Specific Heat, 20°C (J/kg.K) | 419 |
| Thermal conductivity, 20°C (W/m.K) | 21.8 |
| Curie Temperature (°C) | 21 – 49 |
Mechanical Properties
| Â | Hot Worked & Annealed | Cold Worked & Stress Relieved | ||
| 0.2% Proof Stress | 172 N/mm2 | 24.9 ksi | 483 – 690 N/mm2 | 70 – 100 ksi |
| 1.0% Proof Stress | 195 N/mm2 | 28.3 ksi | Â | Â |
| Tensile Strength | 483 N/mm2 | 70 ksi | 621 – 862 N/mm2 | 90 -125 ksi |
| Elongation, 5.65√S0 and 4D | 35% |  | 20% |  |
| Reduction of Area | 60% | Â | 60% | Â |
| Hardness | 110 – 132 HBN |  | 35 HRC max |  |
| Impact Strength (Room Temp) | 160J av (150J min) | Â | 160J av (150J min) | Â |
Key Features
- Excellent corrosion resistance.
- Retains excellent tensile strength and toughness down to cryogenic temperatures.
- Highly resistant to hydrofluoric acid, and resistant to sulphuric and hydrochloric acids under reducing conditions.
- Resistant to chloride stress corrosion, and exhibits very low corrosion rates in flowing seawater.
- ASME Approval for Pressure Vessel application.
Applications
- Process industry applications in sulphuric acid, hydrochloric acid and fatty acid production, hydrofluoric & fluorosilicic acid processes.
- Marine industry and shipbuilding components such as propellers, shafts, fasteners.
- Oil & Gas industry pumps, valves, crude petroleum stills and process vessels.
- Heat exchanger plates
- Electrical and electronic components.
- Boiler feedwater heaters, de-aerating heaters.