What is Inconel? Composition, Properties, and Uses

Inconel® is a family of nickel-based superalloys designed to perform in extreme heat, pressure, and corrosion. These alloys are made primarily from nickel and chromium, along with iron and other metals like molybdenum, niobium, and copper – depending on the specific grade.

Common Inconel grades include 600, 601, 625, 718, and X-750. These grades come in different conditions, such as solution annealed or precipitation hardened, depending on the application.

This article will cover the basics of Inconel – how it’s made, where it’s used, the differences between grades, and how CNC machining supports the production of Inconel parts for demanding environments. If you are interested in CNC machining services for Inconel, contact us with any questions or request a quote to get started.

The Composition of Inconel

Inconel is not a single alloy but a family of nickel-based superalloys. Each type has a slightly different chemical makeup, depending on its intended use. However, all Inconel grades share a few key elements.

Nickel is always the base element and makes up the largest portion of the alloy. Chromium is usually the second most common element. Together, nickel and chromium give Inconel its strength, heat resistance, and corrosion protection.

Iron is present in every Inconel alloy – usually in amounts above 1%. Other elements found in various grades include cobalt, molybdenum, niobium, and titanium. These additions improve toughness, weldability, and resistance to wear.

The original Inconel 600 alloy includes over 72% nickel, 14–17% chromium, 6–10% iron, and around 1% manganese. It also contains small amounts of copper, carbon, silicon, and sulfur.

Different grades use different combinations of elements to handle specific environments and mechanical demands.

Learn how Inconel is different a similar alloy Monel.

The Different Types of Inconel

Inconel includes a range of alloys, each designed to perform under specific conditions. While all are nickel-based and corrosion-resistant, their mechanical properties, temperature limits, and chemical resistances vary by grade.

Inconel 600

The original Inconel alloy. It offers strong resistance to heat and oxidation. It maintains strength at temperatures up to 650 °C and performs well under both hot and cold fatigue. It’s widely used in chemical plant equipment due to its stability in harsh environments.

Inconel 601

This grade provides excellent oxidation resistance at high temperatures. It resists carburization and sulfur-based atmospheres. Inconel 601 is ideal for high-temperature chemical processing and offers good creep strength above 500 °C. The 601GC version has controlled grain structure for improved performance.

Inconel 625

Inconel 625 improves on the corrosion and oxidation resistance of 600 and 601. It holds strength across a wide range of temperatures, from cryogenic conditions up to 980 °C. It’s a good choice for demanding environments that require strength and corrosion resistance over time.

Inconel 718

This precipitation-hardening alloy offers high strength and toughness up to 650 °C. It performs well under both general corrosion and oxidation stress. Inconel 718 is used in aerospace, automotive, and other applications that require durable high-temperature parts.

Inconel X-750

Known for good oxidation and corrosion resistance up to 980 °C. X-750 also performs well at low temperatures and has good formability. It is commonly used in aerospace engines, gas turbines, and structural components exposed to extreme heat.

Inconel 690

This grade has high resistance to chloride corrosion, steam, and high-pressure water environments. It performs well under oxidation and in fluorinated atmospheres. Typical uses include nuclear power systems, nitric acid plants, and waste treatment equipment.

Inconel 792

This alloy contains elevated aluminum content to boost corrosion resistance at very high temperatures. It is best suited for aerospace applications, such as gas turbine blades and parts in chemical rocket combustion chambers.

Each Inconel type serves a specific role in high-performance manufacturing. Choosing the right grade depends on temperature, chemical exposure, and mechanical stress requirements.

The Properties of Inconel

Inconel stands out for its unique combination of strength, heat resistance, and corrosion resistance. These properties make it ideal for high-performance parts used in extreme environments.

One of Inconel’s most important traits is its ability to maintain strength at very high temperatures. While materials like steel may have a higher melting point, they lose mechanical strength and corrosion resistance under extreme heat. Inconel holds its shape and strength under these same conditions. It also forms a stable oxide layer that protects against further corrosion when exposed to high temperatures.

Inconel also performs well at room temperature. The high chromium content provides strong resistance to oxidation and corrosion in both hot and ambient environments. Other elements – such as molybdenum, niobium, and titanium – improve hardness, wear resistance, and toughness.

Some Inconel grades, like Inconel 718, can undergo precipitation hardening. This treatment increases strength even further, allowing the alloy to withstand heavy stress without deformation.

Together, these physical and chemical properties make Inconel a trusted choice for parts that face high temperatures, corrosive conditions, and mechanical load.

What is Inconel Used For?

Inconel is widely used in industries that require strong, corrosion-resistant materials that can hold up under extreme temperatures.

One of the most common applications is in aerospace. Inconel performs well inside jet engines, where heat, pressure, and corrosive fuel create a harsh environment. Parts like fuel nozzles, afterburner rings, and exhaust components are often made from Inconel because it resists heat-related weakening and chemical attack.

Inconel is also used in rockets and space vehicles. Its ability to withstand high heat and mechanical stress makes it suitable for propulsion systems and structural components.

Popular grades for aerospace use include Inconel 625 and Inconel 718. These alloys combine strength, thermal stability, and corrosion resistance, making them reliable in flight-critical applications.

Choose C&H Machine for Inconel CNC Machining Services

C&H Machine is a one-stop machine shop with deep experience in CNC machining Inconel alloys. We use advanced CNC milling, turning, Wire EDM, and Sinker EDM to machine high-strength materials with accuracy and consistency. We are backed by an extensive list of certifications, a full range of equipment, and broad capabilities to meet your project requirements.

Have questions? Contact us to learn more. Ready to get started? Submit your project details through our RFQ form.