Inconel® alloy 625

UNS N06625
W.Nr 2.4856


Springs, seals, nuclear water reactors, and aircraft ducting systems.


Inconel® 625 is a Nickel-Chromium-Molybdenum-Columbium (Niobium) alloy with excellent oxidation resistance, corrosion resistance, and strength at high temperatures. Age-hardening treatments are not required to obtain the high strength properties of Inconel® 625 due to the solid solution effects of molybdenum and columbium on the nickel-chromium matrix. Inconel® 625 is resistant to chloride-ion stress-corrosion cracking, pitting, and stress-corrosion cracking making it suitable for seawater applications. Inconel® 625 can operate from cryogenic temperatures to 700°F (370°C).

Industries Supplied

Marine, Chemical Processing, and Aerospace.

Nominal Composition

Ni: 58.0 min
Cr: 20.0 - 23.0
Mo: 8.0 - 10.0
Cb (Nb): 3.15 - 4.15
Fe: 5.0 max
Co: 1.0 max
Si: 0.5 max
Mn: 0.5 max
Al: 0.4 max
Ti: 0.4 max
C: 0.10 max

Physical Properties

Density: 0.305 lb/in3, (8.44 g/cm3)

Modulus of Elasticity (E): 
At 70°F (20°C): 30.1 x 103 ksi (208 GPa)

Modulus of Rigidity (G): 
At 70°F (20°C): 11.8 x 103 ksi (81.2 GPa)

Coefficient of Expansion:
7.4 µin/in.-°F (70°F to 600°F)
13.3 µm/m-°C (20°C to 300°C)

Electrical Resistivity: 50.8 µΩ.in, (129 µΩ.cm)

Thermal Conductivity: 68 Btu-in/ft2hr-°F, (9.8 W/m-K)

Applicable Specifications

Wire & Bar: AMS 5666, AMS 5837, ASTM B446, AWS A5.14, NACE MR0175 (ISO 15156-3).

Typical Mechanical Properties – Spring Applications

  • Annealed
    • Heat Treatment: 1925°F (1050°C)
    • Tensile Strength: 120 - 150 ksi; (830-1100 MPa)
    • Suggested Operating Conditions: -300°F to 700°F (-184°C to 370°C)

  • Spring Temper
    • Tensile Strength: 200 – 240 ksi; (1380 – 1655 MPa)
    • Suggested Operating Conditions: -300°F to 700°F (-184°C to 370°C‚Äč)

Inconel® is a registered trademark of the Special Metals Corporation group of companies.

For further information Contact:

Phone: 1 847 695 1900 
Elgiloy Specialty Metals - Wire Products
356 N.Cross Street
Sycamore, IL 60178 USA 

Inconel® 625 Wire Alloy

Inconel® 625 wire alloy can be made in flat, square, or even shaped wires. When you begin to analyze it, the two things that immediately stand out are its resistance to oxidation and its scaling at very high temperatures. This makes it vastly superior to other alloys, even ones that are made for high temperatures and varying heating and cooling conditions. The makeup of Inconel® 625 wire also makes it able to withstand corrosive environments as well, even severe ones. In fact, there is almost no impact on the wire in fresh or even salt water. This also holds true for non-acidic environments as well. The high levels of Molybdenum also allows the alloy to be very resistant to pitting.

Further analysis into the Inconel® 625 wire alloy shows that the aversion to corrosion and oxidation is due to the presence of Niobium, or more specifically the way the Molybdenum reacts with the Nickel contained within the wire. The Niobium also provides for strength and toughness, which means that it can be relied upon to function in extreme conditions. The alloy has a good fatigue strength and stress-corrosion cracking resistance to chloride ions, which is why oxidation and corrosion is so rare. 625 is also flexible, both in its side to side mobility, and the variety of places that it can be used.

The main application you will see Inconel® 625 wire alloy being used in is marine environments. The salt level contained in ocean and sea waters normally has a horrific effect on any metal that spends a long period of time in it. However, this alloy can withstand the damaging effects, so it makes it an ideal wire for any machine used underwater. However, there are places that you may not think of that are also beneficial for Inconel® 625 wire. For example, the two properties of steam that most people are aware of is that it is the gaseous state of water, and that it is very hot. Therefore, any machine that uses steam could be damaged by either extreme heat, or natural corrosion that comes from water. As this is the environment that 625 thrives in, you will see it used in things like exhaust systems, ducting systems, engines, and chemical processing equipment.

Inconel® 625 wire is able to withstand these wicked environments because of the way that it was designed. It was specifically made for steam-line piping, but has morphed some over the years. Now, it will hold true at low and high temperatures, and is extremely resistant to creep properties, which is its true strength other than anti-corrosion. Creep conditions happen when high temperatures are met with applied stress. However, Niobium, the chemical alloy that makes up 625 wiring, prohibits creeping, which can be very detrimental to any wiring.

At Elgiloy, we use flexible and custom manufacturing which allows us to provide our customers with the exact amount and shape of Inconel® 625 wire alloy that they need. Every piece of wire is rigorously inspected and will meet the already very high expectations that you have for the product. Because of the environments that Inconel® 625 must thrive in, it is necessary to make sure that it can stand up to those conditions. Our engineers make sure that all qualifications are met, and that all of our customers, international or domestic, are receiving product that they can trust and rely upon.