Inconel 625
Inconel Alloy 625 (UNS designation N06625) is a nickel-based superalloy that possesses high strength properties and resistance to elevated temperatures. It also demonstrates remarkable protection against corrosion and oxidation. Its ability to withstand high stress and a wide range of temperatures, both in and out of water, as well as being able to resist corrosion while being exposed to highly acidic environments makes it a fitting choice for nuclear and marine applications.
| Inconel 625 | |
|---|---|
Cladding overlay in a tube with Inconel 625 | |
| Synonym | Werkstoff 2.4856 |
| Material type | Alloy |
| Alloy properties | |
| UNS identifier | N06625 |
| Alloy type | Nickel-based superalloy |
| Composition |
|
| Physical properties | |
| Density (ρ) | 0.305 lb/cu in (8,442.4 kg/m3) |
| Mechanical properties | |
| Young's modulus (E) | 207.5-147.5 @ 70–1,600 °F (21–871 °C) (annealed) 204.8-148.2 @ 70–1,600 °F (21–871 °C) (solution treated) |
| Tensile strength (σt) | Rod, bar, plate: 120–160 ksi (827–1,103 MPa) (as rolled), 120–150 ksi (827–1,034 MPa) (annealed) |
| Elongation (ε) at break | Rod, bar, plate: 60-30% (as rolled and annealed) |
| Poisson's ratio (ν) | 0.278-0.336 @ 70–1,600 °F (21–871 °C) (annealed) 0.312-0.289 @ 70–1,600 °F (21–871 °C) (solution treated) |
| Hardness—Brinell | Rod, bar, plate: 175-240 (as rolled) |
| Thermal properties | |
| Melting temperature (Tm) | 2,350–2,460 °F (1,288–1,349 °C) |
| Thermal conductivity (k) | 50 BTU/(hr·ft⋅°F) @ −250 °F (−157 °C) – 175 BTU/(hr·ft⋅°F) @ 1,800 °F (982 °C) |
| Specific heat capacity (c) | 0.096-0.160 BTU/(lb⋅°F) (0.402-0.669 J/g⋅°C) @ 0–2,000 °F (−18–1,093 °C) |
| Electrical properties | |
| Permeability (μ) | 1.006 @ 200 Oe (15.92 kA/m) |
| Values displayed for tensile strength, elongation, and hardness are shown for various products under 4 in (10.2 cm) in size, and are measured at room temperature. | |
Inconel 625 was developed in the 1960s with the purpose of creating a material that could be used for steam-line piping. Some modifications were made to its original composition that have enabled it to be even more creep-resistant and weldable. Because of this, the uses of Inconel 625 have expanded into a wide range of industries such as the chemical processing industry, and for marine and nuclear applications to make pumps and valves and other high pressure equipment.
Because of the metal's high Niobium (Nb) levels as well as its exposure to harsh environments and high temperatures, there was concern about the weldability of Inconel 625. Studies were therefore conducted to test the metal's weldability, tensile strength and creep resistance, and Inconel 625 was found to be an ideal choice for welding. Other well known names for Inconel 625 are Haynes 625, Nickelvac 625, Nicrofer 6020, Altemp 625 and Chronic 625