to Metals
to Nickel alloys
Dr. Dmitri Kopeliovich
Non-heat-treatable Nickel-Chromium-Iron Alloys are nickel base alloys, containing 15-22% of chromium (Cr) and up to 50% of iron (Fe) as the major alloying elements.
Non-heat-treatable Nickel-Chromium-Iron Alloys do not contain sufficient amounts of such additional alloying elements like aluminum, silicon, beryllium and titanium; therefore these alloys can not be strengthened by precipitation hardening (in contrast to the heat-treatable Nickel-Chromium-Iron alloys).
Chromium and iron form mono-phase solid solution in nickel.
The alloys may be hardened by cold work.
Annealing of non-heat-treatable Nickel-Chromium-Iron Alloys is conducted at 1740-2150°F (950-1175°C).
Non-heat-treatable Nickel-Chromium-Iron Alloys are identified according to their trade names Inconel, Incoloy and Hastelloy.
Non-heat-treatable Nickel-Chromium-Iron Alloys have very good mechanical strength and high resistance to Creep combined with excellent corrosion resistance in chlorine-ion solutions, to sulfur compounds and to other organic and inorganic compounds.
The alloys are highly resistant to oxidation at high temperatures.
Non-heat-treatable Nickel-Chromium-Iron Alloys possess good machinability, weldability and workability.
The alloys are used for manufacturing gas turbine parts, heat-treating equipment (muffles, retorts), equipment for processing fatting acids, evaporator tubes, chemical processing equipment, distillation columns, combustion systems, heat exchangers, steam generator tubing of nuclear power plants.
| Designation | Cr,% | Fe,% | Mo,% | Al,% | Ti,% | C,% | Others,% | Ni,% |
|---|---|---|---|---|---|---|---|---|
| Inconel 600 | 14-17 | 6-10 | - | - | - | - | - | 72 min. |
| Inconel 625 | 20-23 | 5 max. | 8-10 | - | - | - | Nb3.15-4.15 | 58 min. |
| Incoloy 800 | 19-23 | 39.5 min. | - | 0.15-0.6 | 0.15-0.6 | 0.1 max. | - | 30-35 |
| Incoloy 800HT | 19-23 | 39.5 min. | - | 0.15-0.6 | 0.15-0.6 | 0.06-0.1 | - | 30-35 |
| Hastelloy X | 20.5-23 | 17-20 | 8-10 | - | - | 0.05-0.15 | W 0.2-1Co 0.5-2.5 | 30-35 |