Inconel® alloy 625

---

Applications

Honeycomb, springs, seals, bellows, diaphragms, land-based turbine components, aircraft exhaust ducting, and heat exchangers.

Description

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 Alloy 625 due to the solid solution effects of molybdenum and columbium on the nickel-chromium matrix. I625 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

Automotive, Marine, Chemical Processing, Power Generation, Nuclear, and Aerospace.

Nominal Composition

C: 0.10 max
Mn: 0.50 max
Si: 0.50 max
P: 0.015 max
S: 0.015 max
Cr: 20.0 – 23.0 
Mo: 8.0 – 10.0 
Nb: 3.15 – 4.15 
Co: 1.0 max
Ti: 0.40 max
Al: 0.40 max 
Fe: 5.0 max 
Ni: Balance

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 538°C)

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

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

Applicable Specifications

Strip and Foil: ASTM B443, AMS 5599, AMS 5869, ISO 6208, EN 10095

Typical Mechanical Properties

• 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 – 250 ksi (1380 – 1724 MPa)
  • Suggested Operating Conditions: -300°F to 700°F (-184°C to 370°C)

---

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

For further information Contact:

Email: stripinfo@elgiloy.com
Phone: 1 888 843 2350 
Elgiloy Specialty Metals – Strip Products
1565 Fleetwood Dr.
Elgin, IL 60123 USA 

Inconel® 625 Strip Alloy

The chemical composition that makes up Inconel® 625 strip alloy is Nickel-Chromium-Molybdenum-Columbium or collectively known as Niobium. Characteristics of this alloy are its exceptional resistance to oxidation, corrosion, and its ability to withstand extreme temperatures. Due to the effects that Molybdenum and Columbium provide for the alloy, it is not necessary to use age-hardening treatments on this alloy. It can also withstand temperatures up to 700 degrees. However, perhaps the most practical property that Inconel® 625 alloy has is that it is resistant to chloride-ion stress-corrosion, as well as cracking and pitting. This makes it ideal for any operations that involve salt water, such as machines that operate in the oceans or seas.

There are several other properties of Inconel® 625 strip that makes it beneficial other than its ability to work in seawater. First off, it is non-magnetic. This means that places that are magnetized do not affect the overall performance of the strip. It is also oxidation resistant up to 1800 degrees. This is extremely important because the likelihood of rusting is almost zero. Any piece of equipment that needs to spend a long period of time submerged in water, especially salt water, needs to have some sort of anti-corrosion protection.  Lastly, it has high creep-rupture strength, which is another property that is ideal for engineers working with alloys.

As mentioned before, the main use of Inconel® 625 strip alloy is in machinery in marine environments. However, there are several other places where this alloy can be useful. Aircraft ducting, jet engine exhaust, chemical processing equipment, and nuclear devices also can benefit from utilizing the capabilities of this alloy. Basically, any environment that could have high temperatures, or the possibility of water or corrosion is the perfect place for this particular alloy.

The origin of Inconel® 625 dates back to the 1960s when engineers required a material that could be used for steam-line piping. As steam is both intensely hot, but also is a form of water, the makeup of this alloy is ideal for this situation. Over the years modifications were made from the original composition so it was more resistant to creeping, and increasing its ability to be welded. This expanded the uses for Inconel® 625 strip alloy, and allowed to be used in the chemical processing and nuclear industries to make pumps and valves in high pressure equipment. The Niobium levels within the alloy, along with the extreme environments that it is used in, made weldability a concern. However, studies have shown that 625 is an ideal choice for welding.

Elgiloy offers precision rolling that can be customized to fit the industry and application that our customers intend to use for Inconel® 625. All of our equipment is tested and certified to ensure that you are getting a top-quality product that behaves the exact way that you would expect. It takes a specialized roller to handle Niobium without damaging the integrity of the alloy. When this alloy is used in situations that could literally mean life or death for the people that use it, cutting corners is just not an option. That is why Elgiloy is one of the most trusted companies in the industry in handling Inconel® 625 strip alloy.