What is the Difference Between Inconel 601 and 617?

The inconel alloys belong to a group of metals that have outstanding heat and corrosion as well as oxidation properties. Out of the several grades available, two of the most commonly used grades are Inconel 601 and Inconel 617. What each has, in terms of what makes them suitable for specific applications, is discussed in this blog with respect to differences between Inconel 601 plates and Inconel 617 that include both their composition as well as properties.

1. Composition and Microstructure

The inclusions of the major elements of Inconel 601 are:

Nickel (58% min)

Chromium (21% min)

Iron (balance)

Other constituents include manganese, silicon, carbon and copper.

This composition makes Inconel 601 resistant to strong oxidation and well-balanced strength and toughness.

The composition of Inconel 617 is different as:

Nickel (50-55%)

Chromium (19-23%)

Cobalt (8-12%)

Molybdenum (8-10%)

Iron (balance)

Other constituents include manganese, silicon and carbon.

The addition of cobalt and molybdenum into Inconel 617 makes it have more intense high-temperature strength plus more intense oxidation resistance compared to Inconel 601.

2. High-Temperature Resistance

A striking difference between Inconel 601 and Inconel 617 is the kind of performance each exhibits at temperatures.

Inconel 601 can be continuously exposed up to a maximum temperature of 2200°F (1204°C). It can intermittently be exposed up to a maximum temperature of 2400°F (1315°C). This material is useful in the industrial furnace components, gas turbine engines, and certain heat treating applications.

Inconel 617 is more suitable wherever temperatures more than 2000°F (1093°C) are expected. It can perform very well in gas turbines, combustion chambers, and many other high-temperature processes.

3. Corrosion Resistance

Both alloys have superb corrosion and oxidation-resistant properties but excel in dissimilar environments:

Inconel 601 is highly resistant to oxidation and carburization in elevated temperatures and is suitable for oxidation and reducing environments. The alloy also exhibits an excellent resistant capability to sulfuric and phosphoric acids.

Inconel 617 exhibits outstanding resistance to oxidation and carburization, especially at elevated temperatures. Its composition enables it to perform satisfactorily in atmospheres that contain hydrogen, chloride, and sulfur compounds.

4. Mechanical Properties

Mechanical properties describe the suitability of the material for a specific application:

Inconel 601 also exhibits outstanding tensile strength, yield strength, and ductility. The tensile strength of Inconel 601 increases with temperature, which allows for its use in many applications at high temperature conditions. Its yield strength is roughly about 30,000 psi or 207 MPa at room temperature.

Inconel 617 has higher strength at high temperatures than 601, about yield strength of some 40,000 psi (276 MPa) at room temperature. Because these components are stress-critical, with high thermal and mechanical loading, the superiority of strength is an important advantage.

5. Applications

The variations in the composition and properties of Inconel 601 and 617 have led to differences in applications:

Industrial furnace components

Heat treat baskets

Gas turbine components

Kilns and combustion chambers

Chemical processing equipment

Inconel 617 is generally used in:

Gas turbines and combustors

High-temperature industrial furnaces

Power generation heat exchangers

Aerospace

Components that have to endure high-temperature applications

Conclusion

To put it all together, both Inconel 601 and Inconel 617 are high-performance alloys for extreme environments, but they possess different characteristics that enable them to serve in different applications.
High-temperature oxidation and carburization-resistant applications can be satisfactory with Inconel 601 plates, though high-temperature strength along with superior corrosion resistance application makes Inconel 617 plates unparalleled in suitability. Before you choose the right alloy for your project, there should be consideration of specific requirements related to temperature, mechanical stress, or environmental conditions.