Alloy 825 (Tube) (UNS N08825)
Description:
Alloy 825 is a nickel-iron-chromium alloy with additions of molybdenum, copper and titanium (NiCr21Mo), supplied in the hot worked and annealed condition. The alloy achieves good mechanical properties from cryogenic to medium-high temperatures (5400C) and can be significantly strengthened if required through cold working.
The high nickel content ensures resistance to stress corrosion cracking, combined with molybdenum and copper to strongly resist reducing environments such as sulphuric and phosphoric acids. Chromium aids in the resistance to oxidising environments such as nitric acid and titanium inhibits intergranular corrosion, and overall resistance to pitting and crevice corrosion.
Key Features:
- Excellent corrosion resistance in a wide variety of corrosive environments including seawater and industrial acids
- Readily formable and weldable
- Excellent resistance to stress corrosion cracking
Applications:
- Chemical process equipment
- Pollution control systems and wet scrubbers
- Waste heat recovery exchangers
- Tanks, vessels and agitators
- Downhole equipment for corrosive/sour service
- Nuclear reprocessing and handling
Chemical Composition:
Cr | Ni | Mo | Co | Nb (+Ta) | Ti | W | Cu | C | Mn | N | Si | P | S | Fe | Al | |
Min | 19.50 | 38.00 | 2.50 | 0.60 | 1.50 | 22.00 | ||||||||||
Max | 23.50 | 46.00 | 3.50 | 1.20 | 3.00 | 0.05 | 1.00 | 0.50 | 0.03 | 0.20 |
Mechanical Properties:
0.2% Proof Stress | 241 N/mm2 | 35 ksi |
Tensile Strength | 518 N/mm2 | 75 ksi |
Elongation, 5.65√S0 and 4D | 30% | |
Reduction of Area | ||
Hardness (Brinell) | 331 max. |
Notes:
- Tensile testing shall be carried out in accordance with ASTM A370 or EN10002-1
- Minimum properties quoted (tested at room temperature in a longitudinal direction)
- Testing performed on each melt of material per heat treatment batch
Physical Properties:
Density (Kg.m-1) | 81.4 |
Magnetic Permeability (20°C) | 1.005 |
Curie Temperature (°C) | -196 |
Young’s Modulus (N/mm2) | 196 |
Specific Heat, 20°C (J/(g.K)) | 440 |
Specific Electrical Resistance, 20°C (Ω-m) | 0.00113 |
Thermal conductivity, 20°C (W/(m.K)) | 10.8 |
Mean coefficient of thermal expansion, 20-100°C (/K) | 14.1 x 10-6 |
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