ASME SB163 UNS N08825 Incoloy 825 Nickel Alloy Seamless Tubes For Chemical Industry
ASME SB163 UNS N08825 Incoloy 825 Nickel Alloy Seamless Tubes For Chemical Industry
ASME SB163 UNS N08825 Nickel Alloy Seamless Tubes are seamless tubes made from UNS N08825, a nickel-iron-chromium-molybdenum-copper alloy commonly known as Incoloy 825 / Alloy 825. UNS N08825 combines high nickel content with chromium, molybdenum, copper, and titanium. This gives it excellent resistance to both oxidizing and reducing acids, good resistance to chloride-ion stress corrosion cracking, and good mechanical properties over a wide temperature range. ASME SB163 UNS N08825 Nickel Alloy Seamless Tubes are widely used in heat exchangers, condensers, evaporators, chemical processing equipment, marine systems, nuclear fuel reprocessing, and other aggressive-corrosion services.
Main Features:
Multi-media corrosion resistance
Thermal stability
Excellent fabricability
Moderate high-temperature performance
Good weldability and formability
Suitable for high-purity and nuclear applications
Chemical Composition(%):
| Element | Content Range |
| Ni | 38.0 – 46.0 |
| Cr | 19.5 – 23.5 |
| Fe | Remainder |
| Mo | 2.50 – 3.50 |
| Cu | 1.50 – 3.00 |
| Ti | 0.60 – 1.20 |
| C | ≤ 0.05 |
| Mn | ≤ 1.00 |
| Si | ≤ 0.50 |
| S | ≤ 0.030 |
| P | ≤ 0.030 |
| Al | ≤ 0.20 |
Mechanical Properties:
| Tensile Strength, Rm | ≥ 586 MPa (≥ 85 ksi) |
| Yield Strength, Rp0.2 | ≥ 241 MPa (≥ 35 ksi) |
| Elongation (50 mm gauge length) | ≥ 30% |
| Hardness | Max 217 HB / 95 HRB |
Surface Finishes:
1. Bright Annealed (BA):
Final heat treatment performed in a controlled protective atmosphere furnace. The tube surface is smooth, silvery bright, free of oxide scale. Typical for small OD thin-wall tubes for precision heat exchangers; no pickling after annealing.
2. Pickled & Annealed (PA):
Annealed in air or low-protection atmosphere, followed by acid pickling and passivation to remove oxide and heat tint. Matte silver-grey surface, the most widely used finish for heat exchanger tubes.
3. Ground / Polished Finish:
Mechanically ground or polished to specified Ra roughness.
Main Applications:
Heat exchangers, condensers, evaporators, coolers, and feedwater heaters.
Chemical processing: sulfuric acid, phosphoric acid, nitric acid, pickling lines.
Nuclear fuel reprocessing and radioactive waste handling.
Oil and gas: sour gas, offshore, downhole, and pipeline equipment.
Marine and seawater systems, desalination plants.
Pollution control: flue gas desulfurization scrubbers.
Pulp and paper: bleach plants and digesters.
Food, and high-purity process systems.
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