Alloy 825 / 2.4858
Alloy 825 is a titanium-stabilized, fully austenitic nickel-iron-chromium alloy with additions of copper and molybdenum. Alloy 825 is characterized by:
Approval for pressure vessels with operating temperatures up to 425 ° C
good resistance to stress corrosion cracking
good resistance to oxidizing and non-oxidizing hot acids
good mechanical properties at both room and elevated temperatures up to 550 ° C
satisfactory resistance to pitting and crevice corrosion
Material Data Sheet
| Material Designation | 2.4858 |
|---|---|
| Alloy | Alloy 825 |
| EN Material Symbol | NiCr21Mo |
| UNS | N 08825 |
| VdTÜV Datasheet | 432/1 |
| ISO | NiFe30Cr21Mo3 |
Main fields of application of alloy 825
Typical examples for the use of 825 are as follows:
-Chemical plants
Air-cooled heat exchangers in LNG process (LPG)
Heat exchangers, evaporators, scrubbers, fork tubes, in the phosphoric acid production
Components in sulfuric acid pickling lines, such as heating coils, tanks, boilers, baskets and chains
Fuel element for a variety of media, such as dissolver sulfuric and nitric acid, sodium hydroxide, etc., which are used in the recycling process
Food preparation
seawater-cooled heat exchangers, offshore pipelines, pipes and parts in natural gas operation
Chemical composition of alloy 825
| C | Si | Mn | P | S | Cr | Mo |
|---|---|---|---|---|---|---|
| % | ≤ % | ≤ % | ≤ % | ≤ % | % | % |
| 0.025 | 0.5 | 1.0 | 0.02 | 0.015 | 19.5-23.5 | 2.5-3.5 |
| Ni | Al | Co | Cu | Fe | Ti | B |
| % | % | ≤ % | ≤ % | % | % | ≤ % |
| 38.0-46.0 | 0.2 | 1.0 | 1.5-3.0 | rest | 0.6-1.2 | 0-0.006 |
Characteristics of alloy 825
| Temperature Range | up to 550°C |
|---|---|
| Density | 8.1 g/cm³ |
| Melting Range | 1370°C – 1400°C |
| Elongation at break of Alloy 825 | 30 % |
| ISO-V notch impact toughness | ≥ 150 J/cm² at room temperature, lengthwise (only bars and forgings) |
| ≥ 100 J/cm² at room temperature, across |
Filler metal (for welding with alloy 825)
Alloy 825 can be welded by all conventional methods.
The following welding is recommended:
WIG/MIG2.4831
SG- NiCr21Mo9NbFilter Rod2.4621
EL- NiCr20Mo9Nb