24 July 2021 Incoloy®
Incoloy 825 Alloy Steel Pipe
Incoloy 825 is a nickel-iron-chromium alloy with additions of molybdenum, copper and titanium. 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.
Incoloy 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 |
APPLICATIONS
Applications include chemical processing, pollution control, oil and gas
recovery, acid production, pickling operations, nuclear fuel reprocessing, and handling of radioactive wastes.
FORGING
The forging temperature range for this alloy is 2150/1600ºF (1180/870ºC). Optimum corrosion resistance is obtained when finish forging is carried out between 1800/1600°F (980/870ºC). Forgings should be cooled in air or faster.
Heavy sections may be susceptible to intergranular corrosion, hence a stabilizing anneal should be carried out on such forged parts.
HEAT TREATMENT
A stabilizing anneal is carried out in the temperature range 1700/1800ºF (930/980ºC), followed by rapid cooling, to provide optimum corrosion resistance and mechanical properties.
MACHINABILITY
The alloy is readily machined, preferably in the annealed condition. The usual recommendations for high-nickel alloys apply, namely positive feeds, slow speeds and rigid tools and equipment.
WELDABILITY
Incoloy alloy 825 is readily welded by all conventional methods. Advice should be taken from the supplier on the electrodes and filler metal to be used.