Alloy 625 / 2.4856
Alloy 625 is a low carbon (0.03%) nickel-chromium-molybdenum-niobium alloy which has excellent corrosion resistance to a wide range of corrosive media. Alloy 625 is normally supplied in annealed condition for wet corrosion applications and is TÜV-approved for pressure vessels in the temperature range from -196°C to 450°C. In annealed condition (grade 1) Alloy625 is characterized by:
good mechanical property
Resistance to chlorine-induced stress corrosion cracking
high resistance to mineral acids such as nitric, phosphoric, sulfuric, and hydrochloric acid
good resistance to alkalis and organic acids
exceptional resistance to pitting, crevice, erosion and intergranular corrosion
Material Data Sheet
| Material Designation | 2.4856 |
|---|---|
| Alloy | Alloy 625 |
| EN Material Symbol | NiCr22Mo9Nb |
| UNS | N 06625 |
| VdTÜV Data Sheet | 499 |
Main fields of application of alloy 625
2.4856 is used for:
Natural gas pipelines
Production systems and pipe coverings of riser pipes in oil production
Preparation of phosphoric acid
Shipbuilding and marine water lines
Plants for the treatment of radioactive waste
Flue gas scrubbers and dampers in flue gas cleaning systems
Chemical composition of alloy 625
| C | Si | Mn | P | S | Cr | Mo |
|---|---|---|---|---|---|---|
| % | ≤ % | ≤ % | ≤ % | ≤ % | % | % |
| 0.03 | 0.4 | 0.5 | 0.01 | 0.01 | 21.0-23.0 | 8.0-10.0 |
| Mo | Ni | Al | Co | Fe | Ti | Nb+Ta |
| % | % | % | ≤ % | ≤ % | % | % |
| 8.0-10.0 | rest | 0.4 | 1.0 | 0.4 | 0.4 | 3.2-3.8 |
Characteristics of alloy 625
| Temperature Range | Wet corrosion and high-temperature variant possible |
|---|---|
| Density | 8.44 g/cm³ |
| Melting Range | 1290°C - 1350°C |
| ISO-V notch impact toughness (average at room temperature acc. to DIN EN 10045 part 1) | lengthwise ≥ 125 J/cm² |
| across ≥ 100 J/cm² |
Filler metal (for welding with alloy 625)
Welding rods and wire electrodes:
Nicrofer S 6020 – FM 625 (2.4831)
DIN EN ISO 18274: S Ni 6625 (NiCr22Mo9Nb)
UNS N06625
AWS: 5.14: ErNiCrMo3
Covered electrodes:
DIN EN ISO 14172: E Ni 6625 (NiCr22Mo9Nb)
(2.4621)
UNS W86112
AWS A5.11: ENiCrMo-3