Alloy 825 is a Nickel-iron-chromium alloy with additions of molybdenum, copper and titanium. The alloys chemical composition provides exceptional resistance to many corrosive environments. The Nickel content is sufficient for resistance to Chloride-ion stress corrosion cracking. The nickel, combined with molybdenium and copper, also gives outstanding resistance to reducing environments such as those containing sulfuric and phosphoric acid. The molybdenium also aids resistance to pitting and crevice corrosion. The alloys Chromium content confers resistance to a variety of oxidizing substances such as nitric acid, nitrates and oxidizing salts. The titanium addition, with appropriate heat treatment, will stabilize the alloy against sensitization to intergranular corrosion.
Availability – Alloy 825
Seamless Pipe 1/2″ – 8″
Welded Pipe 8″ – 12″
Butt-Weld Fittings 1/2″ – 8″
Flanges 1/2″ – 8″
Bar 1″ – 6″
Specifications – Alloy 825
| ASTM | B443, B705, B366, B425, B564 |
| ASME | SB443, SB705, SB366, SB925, SB564 |
Design Features – Alloy 825
| C | CR | FE | NI | AI | TI | CU | MO |
|---|---|---|---|---|---|---|---|
| Max | Max | Max | Max | ||||
| 0.05% | 19.25%-23.5% | 0.5% | 38% -46% | 0.2% | 0.6% – 1.20% | 1.5% – 3.0% | 2.5% – 3.5% |
Design Features – Alloy 825
- Exceptional resistance to stress corrosion cracking as well as oxidizing and non-oxidizing hot acids
- Satisfactory pitting and crevice corrosion resistance
- Good mechanical properties from room temperature to 1020° F (549° C)
- Appropriate for pressure-vessel use at wall temperature to 800° F (427°C)
- Sulfuric acid pickling plant equipment, including heating coils, tanks, crates, baskets and chains
- Fuel element dissolvers
- Offshore product piping system components and tubes sour gas service
- Seawater-cooled heat exchangers
- Paper industry – pipe digesters
- Pipelines for wet sulfur dioxide gas
- Phosphoric acid production equipment, including heat exchangers, evaporators and scrubbers
- LPG (liquid petroleum gas) processing equipment, including air-cooled heat exchangers
Tensile Requirements – Alloy 825
Tensile Strength (KSI): 85
Yield Strength (KSI): 35
KSI can be converted to MPA (Megapascals) by multiplying by 6.895.