Inconel Chemical Composition Chart: Grades 600, 625, 718, 800 and 825 Explained
The chemical composition of Inconel is the only factor that can determine the performance of each grade in extreme service conditions. From corrosion resistance to weldability, a knowledge of just how much nickel, chromium, molybdenum and niobium exists within your selected Inconel grade is the key to determining all of this. This guide brings together verified and ASTM-standardized composition information for the 5 most commonly used Inconel grades: Inconel 600, Inconel 625, Inconel 718, Inconel 800 and Inconel 825 in a clear comparison chart, along with a breakdown of each grade. It’s not just about the word but composition of Inconel is important to understand. The composition limits are used to verify the mill test reports, to choose the filler metal for welds, to write the purchase order and to qualify the welding procedure. Failure may occur prematurely if the wrong grade is used or material is accepted that is outside the composition limits.
What Is Inconel?
Inconel is a registered trade mark of Special Metals Corporation of a group of austenitic nickel chromium-based super alloys for extreme operating conditions. All of the Inconel grades are basically composed of nickel, generally from 30% to more than 72%, and the major secondary alloying element is chromium. The chromium metal has the ability to create a protective oxide layer on the material to provide good resistance to a high-temperature environment. Inconel alloys may be classified as solid solution-strengthened alloys, like Inconel 600 and Inconel 625, and precipitation hardening alloys, like Inconel 718. The properties and uses of each alloy will depend on its composition.
Alloying Elements and Their Roles in Inconel Grades
The Inconel chemical composition is composed of nickel and chromium in main components, followed by iron, molybdenum, niobium, cobalt, titanium, aluminum, manganese, silicon, carbon, sulfur, and copper. The proportion of these elements will differ according to the type of grade to be used and the applications of the Inconel. Also the Inconel material comes in different grades such as 600, 625, 718, 800 and 825. The chemical composition of every alloy is different and the information regarding these grades are given below.
Inconel 600 Chemical Composition
Element | Min % | Max % | Typical Role |
Nickel (Ni) | 72.0 | — | Base element; resists chloride-ion SCC and reducing media |
Chromium (Cr) | 14.0 | 17.0 | Oxidation resistance; forms Cr₂O₃ protective layer |
Iron (Fe) | 6.0 | 10.0 | Cost balance; strengthens the nickel-chromium matrix |
Carbon (C) | — | 0.15 | Carbide former; controlled to limit sensitization |
Manganese (Mn) | — | 1.0 | Deoxidiser during melting |
Silicon (Si) | — | 0.50 | Deoxidiser; minor strengthening |
Sulfur (S) | — | 0.015 | Controlled to prevent hot cracking |
Copper (Cu) | — | 0.50 | Residual element |
Explore Inconel 600 Pipe and Tube for available product forms, wall schedules and applicable ASTM/ASME specifications.
Inconel 625 Chemical Composition
Element | Min % | Max % | Typical Role |
Nickel (Ni) | 58.0 | — | Austenitic matrix; corrosion resistance in reducing media |
Chromium (Cr) | 20.0 | 23.0 | Oxidation resistance; passive film stability |
Molybdenum (Mo) | 8.0 | 10.0 | Pitting and crevice corrosion resistance; solid-solution strength |
Niobium + Tantalum | 3.15 | 4.15 | Solid-solution strengthening; stabilises against sensitization |
Iron (Fe) | — | 5.0 | Residual element |
Carbon (C) | — | 0.10 | Controlled to prevent carbide sensitization |
Aluminum (Al) | — | 0.40 | Oxidation resistance at very high temperatures |
Titanium (Ti) | — | 0.40 | Residual element |
Cobalt (Co) | — | 1.0 | Residual; if determined |
See Inconel 625 Pipe and Tube for available diameters, schedules and seamless versus welded options.
Inconel 718 Chemical Composition
Element | Min % | Max % | Typical Role |
Nickel (Ni) | 50.0 | 55.0 | Austenitic FCC matrix; precipitation hardening base |
Chromium (Cr) | 17.0 | 21.0 | Oxidation and corrosion resistance |
Iron (Fe) | Balance | — | Cost element; matrix filler |
Niobium + Tantalum | 4.75 | 5.50 | Primary strengthening precipitate (Ni₃Nb, γ″ phase) |
Molybdenum (Mo) | 2.8 | 3.3 | Solid-solution strengthening; corrosion resistance |
Aluminum (Al) | 0.20 | 0.80 | Secondary γ′ precipitate (Ni₃Al) formation |
Titanium (Ti) | 0.65 | 1.15 | Secondary γ′ precipitate; grain boundary carbides |
Carbon (C) | — | 0.08 | Controlled to prevent grain boundary sensitization |
Cobalt (Co) | — | 1.0 | Residual element |
Copper (Cu) | — | 0.30 | Residual element |
Boron (B) | — | 0.006 | Grain boundary strengthening |
Browse Inconel 718 Pipe and Tube for product specifications and material certifications.
Inconel 800 Chemical Composition
Element | Min % | Max % | Typical Role |
Nickel (Ni) | 30.0 | 35.0 | Austenitic stabiliser; corrosion resistance |
Iron (Fe) | Balance (approx. 39.5%) | — | Major matrix element; cost reduction |
Chromium (Cr) | 19.0 | 23.0 | High-temperature oxidation and carburization resistance |
Aluminum (Al) | 0.15 | 0.60 | High-temperature oxidation resistance; age-hardening (800H/HT) |
Titanium (Ti) | 0.15 | 0.60 | Grain stabilisation; age-hardening potential |
Carbon (C) | — | 0.10 | Controlled; higher in 800H (0.05-0.10) for creep strength |
Manganese (Mn) | — | 1.50 | Deoxidiser |
Silicon (Si) | — | 1.00 | Deoxidiser |
Sulfur (S) | — | 0.015 | Controlled for hot workability |
Inconel 825 Chemical Composition
Element | Min % | Max % | Typical Role |
Nickel (Ni) | 38.0 | 46.0 | Corrosion resistance in reducing acids; chloride SCC immunity |
Iron (Fe) | ≥22.0 | — | Major matrix constituent |
Chromium (Cr) | 19.5 | 23.5 | Resistance to oxidizing media and pitting |
Molybdenum (Mo) | 2.5 | 3.5 | Pitting and crevice corrosion resistance in chloride environments |
Copper (Cu) | 1.5 | 3.0 | Resistance to sulfuric and phosphoric acids in reducing conditions |
Titanium (Ti) | 0.6 | 1.2 | Stabilises against intergranular corrosion (sensitization control) |
Carbon (C) | — | 0.05 | Very low; prevents sensitization |
Aluminum (Al) | — | 0.20 | Residual element |
Manganese (Mn) | — | 1.00 | Deoxidiser |
Silicon (Si) | — | 0.50 | Deoxidiser |
Discover Inconel Plates and Sheets and Inconel Round Bars available for Inconel 825 and other grades.
Different Grades of Inconel Material
Inconel material codes include grade numbers like Inconel 600, Inconel 625, Inconel 718 and Inconel 800. Each grade has a specific chemical composition and is designed for specific performance needs and applications.
Trade Name | ASTM / ASME Standard | UNS Number |
600 | ASTM B167 | UNS N06600 |
601 | ASTM B167 | UNS N06601 |
N06603 | ASTM B167 | UNS N06603 |
N06690 | ASTM B167 | UNS N06690 |
N06693 | ASTM B167 | UNS N06693 |
N06025 | ASTM B167 | UNS N06025 |
N06045 | ASTM B167 | UNS N06045 |
N06696 | ASTM B167 | UNS N06696 |
600 | ASTM B163 | UNS N06600 |
601 | ASTM B163 | UNS N06601 |
690 | ASTM B163 | UNS N06690 |
Applications of Inconel Materials
- Aerospace Industry
- Oil and Gas Industry
- Petrochemical Industry
- Chemical Processing Industry
- Power Generation Industry
- Marine Industry
- Nuclear Industry
- Heat Treatment and Furnace Industry
Why Choose Steel Pipe & Tubes?
Stellar Alloys manufactures and exports Inconel pipes, tubes, bars, plates and fittings across all five grades covered in this guide, certified to ASTM and ASME standards for aerospace, oil and gas, and chemical processing applications.
Conclusion:
To understand the chemical composition of Inconel material, it is important to know about the different grades for demanding industrial applications. Each of the alloys, including Inconel 600, 625, 718, 800 and 825 consist of a unique combination of nickel, chromium, molybdenum, niobium and additional alloying elements that influence the strength, corrosion resistance and high temperature characteristics of each alloy. When deciding on the most appropriate material for their working environment, engineers and buyers can compare the Inconel chemical composition chart. We manufacture and supply Inconel Products of top quality in different grades and shapes which have International standards for reliable performance in different industrial applications at Steel Pipe & Tubes.
Frequently Asked Questions
Inconel is primarily composed of nickel and chromium, with smaller amounts of iron, molybdenum, niobium, cobalt, titanium, aluminum, and other alloying elements depending on the grade.
Common elements in Inconel alloys include nickel, chromium, iron, molybdenum, niobium, cobalt, titanium, aluminum, manganese, silicon, carbon, sulfur, and copper.
Each Inconel grade has a different chemical composition. The percentages of nickel, chromium, molybdenum, niobium, titanium, and other elements vary to provide specific mechanical properties and corrosion resistance.
The nickel content in Inconel typically ranges from 30% to over 72%, depending on the specific alloy grade.
Chromium is added to Inconel alloys to improve oxidation and corrosion resistance by forming a protective oxide layer on the material’s surface.
Inconel 600 contains higher nickel and chromium, making it suitable for high-temperature oxidation. Inconel 625 contains molybdenum and niobium, providing better corrosion, pitting, and seawater resistance.
Inconel 718 is the most widely used aerospace grade due to its high strength, excellent heat resistance, and outstanding mechanical performance in jet engines, turbine components, and aerospace fasteners.