Nickel Alloy 625 is used both for its high strength and outstanding aqueous corrosion resistance. The strength of Nickel Alloy 625 is primarily a solid solution effect from molybdenum and columbium. Nickel Alloy 625 has excellent weldability. The matching filler metals are often used for dissimilar metal joining and to weld the aqueous corrosion alloy AL-6XN®.
| Zeon Grade | Alloy Name | UNS | EN / DIN / W Nr. | Trademarks |
|---|---|---|---|---|
| Zeon625 | Alloy 625 | UNS N06625 | 2.4856 | Inconel 625 |
| Chemistry, % | AMS 4967 | |
|---|---|---|
| Min | Max | |
| Chromium | 20.00 | 23.0 |
| Nickel | 58.00 | Balance |
| Molybdenum | 8.00 | 10.00 |
| Cobalt | - | 1.00 |
| Columbium + Tantalum | 3.15 | 4.15 |
| Aluminum | - | 0.40 |
| Titanium | - | 0.40 |
| Carbon | - | 0.10 |
| Iron | - | 5.00 |
| Manganese | - | 0.50 |
| Silicon | - | 0.50 |
| Phosphorus | - | 0.015 |
| Sulfur | - | 0.015 |
| Properties | Metric |
|---|---|
| Density | 0.305 lb/inch3 |
| Melting point | 2350-2460°F |
| Properties | Values |
|---|---|
| Ultimate Tensile Strength | 120 ksi |
| 0.2% Yield | 60 ksi |
| Elongation (2”) | 30% |
| Temp°F | Coefficient of Thermal Exp. in/in °F x 10-6 | Thermal Conductivity Btu. ft/ft2.hr°F | Modulus of Elasticity Dynamic psi x 106 |
|---|---|---|---|
| 70 | - | 5.7 | 29.8 |
| 400 | 7.3 | 7.2 | 28.4 |
| 600 | 7.4 | 8.2 | 27.5 |
| 800 | 7.6 | 9.1 | 26.6 |
| 1000 | 7.8 | 10.1 | 25.6 |
| 1200 | 8.2 | 11.0 | 24.4 |
| 1400 | 8.5 | 12.0 | 23.1 |
| 1600 | 8.8 | 13.2 | - |
| Corrosion Resistance Properties of Alloy 625 |
|---|
| UNS N06625 has good resistance to oxidation and scaling at high temperatures. At 1800°F, scaling resistance becomes a significant factor in service. It is superior to many other high temperature alloys under cyclic heating and cooling conditions. The combination of the alloyed elements in UNS N06625 enables it to withstand a wide variety of severe corrosive environments. There is almost no attack in mild environments, such as fresh and seawater, neutral pH environments, and alkaline media. The chromium content of this alloy results in superior resistance to oxidizing environments. The high molybdenum content makes UNS N06625 very resistant to pitting and crevice corrosion. |
| Workability | Because the high-temperature strength of UNS N06625 is extremely higher than that of Type 304, care is required when hot working. The cold workability of UNS N06625 is basically the same as that of standard austenitic stainless steels such as Type 304, Type 316, etc. However, the fact that this is a high strength material must be considered in cold working. |
|---|---|
| Weldability | Various welding methods are applicable in the same manner as with the standard austenitic stainless steels, including shielded metal arc welding, TIG welding, and plasma welding. Susceptibility of NAS 625 to solidification cracking is higher than that of Type 304. |
| Heat Treatment | Annealing of UNS N06625 is normally performed at 871℃ and higher followed by being quenched in water or rapidly cooled by other means. Solution annealing of UNS N06625 is normally performed at 1093℃ and higher followed by being quenched in water or rapidly cooled by other means. |
| Pickling | A mixture of nitric acid and fluoric acid is used in pickling. However, because descaling is somewhat difficult in comparison with Type 304, alkali immersion before acid pickling, and if possible, shot blasting are extremely effective. |
| Applications | Chemical plants, nuclear power, seawater applications, jet engine parts, aircraft material, heat treatment furnace material, evaporators |