Incoloy 825 is a Nickel-Iron-Chromium alloy with additions of Molybdenum and Copper. It has excellent resistance to both reducing and oxidising acids, to stress-corrosion cracking and to localised pitting and crevice corrosion. It is also especially resistant to sulphuric and phosphoric acids.
Incoloy® 825 is also known as Nicrofer 4221, Superimphy 82 and Ferrochronin 825.
| Element | Min % | Max % |
| Ni | 38.00 | 46.00 |
| Co | – | 2.00 |
| Cu | 1.50 | 3.00 |
| Cr | 19.50 | 23.50 |
| Mo | 2.50 | 3.50 |
| Al | – | 0.20 |
| C | – | 0.05 |
| Si | – | 0.50 |
| Mn | – | 1.00 |
| S | – | 0.03 |
| Ti | 0.60 | 1.20 |
| Fe | Bal | |
Density
8.14 g/cm³ | 0.294 lb/in³
Melting Point
1400°C | 2550°F
Coefficient of Expansion
14.0 μm/m °C (20 – 100°C) | 7.8 x 10-6 in/in °F (70 – 212°F)
Modulus of Rigidity
75.9 kN/mm² | 11009 ksi
Modulus of Elasticity
196 kN/mm² | 28428 ksi
Heat Treatment of Finished Parts
| Condition as supplied by Alloy Wire | Type | Temperature | Time (Hr) | Cooling | |
| °C | °F | ||||
| Annealed or Spring Temper | Stress Relieve | 450 – 470 | 840 – 880 | 0.5 – 1 | Air |
Properties
| Condition | Approx. tensile strength | Approx. operating temperature | ||
| N/mm² | ksi | °C | °F | |
| Annealed | 600 – 800 | 87 – 116 | -100 to +250 | -145 to +480 |
| Spring Temper | 800 – 1100 | 116 – 159 | -100 to +250 | -145 to +480 |