Other common names: Alloy 825
Incoloy 825 is a nickel-iron-chromium alloy with additions of molybdenum and copper. This nickel steel alloy’s chemical composition is designed to provide exceptional resistance to many corrosive environments. It is similar to alloy 800 but has improved resistance to aqueous corrosion. It has excellent resistance to both reducing and oxidizing acids, to stress-corrosion cracking, and to localized attack such as pitting and crevice corrosion. Alloy 825 is especially resistant to sulfuric and phosphoric acids. This nickel steel alloy is used for chemical processing, pollution-control equipment, oil and gas well piping, nuclear fuel reprocessing, acid production, and pickling equipment.
Product Forms
- Sheet
- Plate
- Bar
- Pipe & Tube (welded & seamless)
- Fittings (i.e. flanges, slip-ons, blinds, weld-necks, lapjoints, long welding necks, socket welds, elbows, tees, stub-ends, returns, caps, crosses, reducers, and pipe nipples)
- Wire
What are the characteristics of Incoloy 825?
- Excellent resistance to reducing and oxidizing acids
- Good resistance to stress-corrosion cracking
- Satisfactory resistance to localized attack like pitting and crevice corrosion
- Very resistant to sulfuric and phosphoric acids
- Good mechanical properties at both room and elevated temperatures up to approximately 1020° F
- Permission for pressure-vessel use at wall temperatures up to 800°F
Alloy 825 (UNS N08825) Chemical Composition, %
| Ni | Fe | Cr | Mb | Cu | Ti | C | Mn | S | Si | Al |
|---|---|---|---|---|---|---|---|---|---|---|
| 38.0-46.0 | 22.0 min | 19.5-23.5 | 2.5-3.5 | 1.5-3.0 | .6-1.2 | 0.05 max | 1.0 max | 0.03 max | 0.5 max | 0.2 max |
Corrosion Resistance
Alloy 825 has a high level of corrosion resistance. It resists general corrosion, pitting, crevice corrosion, intergranular corrosion, and stress-corrosion cracking in both reducing and oxidizing environments.
In what applications is Incoloy 825 used?
- Chemical Processing
- Pollution-control
- Oil and gas well piping
- Nuclear fuel reprocessing
- Components in Pickling equipment like heating coils, tanks, baskets and chains
- Acid production
ASTM Specifications
| Pipe Smls | Pipe Welded | Tube Smls | Tube Welded | Sheet/Plate | Bar | Forging | Fitting |
|---|---|---|---|---|---|---|---|
| B423 | B424 | B425 | B564 | B366, B564 |
General Mechanical Properties
| Tensile (ksi) | .2% Yield (ksi) |
|---|---|
| 85 | 30-35 |
Alloy 825 has good mechanical properties from cryogenic temperatures to moderately high temperatures. However, exposure to temperatures above 1000° F can result in microstructural changes that significantly lower ductility and impact strength. Alloy 825 should not be used at temperatures where creep-rupture properties are design factors.