INCONEL® Alloy 718: Comprehensive Product Introduction
Introduction to INCONEL® Alloy 718
INCONEL® alloy 718 is a high-strength, corrosion-resistant nickel-chromium alloy known for its excellent mechanical properties and versatility in extreme environments. Developed for applications requiring high strength and oxidation resistance at elevated temperatures, INCONEL® 718 finds extensive use in aerospace, gas turbines, nuclear reactors, and other demanding industries. This article provides a detailed overview of INCONEL® alloy 718, covering its chemical composition, mechanical properties, performance at different temperatures, corresponding grades, industry applications, available forms, sizes, production standards, as well as welding, processing, heat treatment, cold processing, and polishing information across various countries.
Chemical Composition of INCONEL® Alloy 718
INCONEL® alloy 718 is formulated with precise elements to achieve its exceptional properties:
| Element | Composition (%) |
|---|---|
| Nickel (Ni) | 50.0-55.0 |
| Chromium (Cr) | 17.0-21.0 |
| Iron (Fe) | 18.5 min |
| Niobium (Nb) | 4.75-5.50 |
| Molybdenum (Mo) | 2.80-3.30 |
| Titanium (Ti) | 0.65-1.15 |
| Aluminum (Al) | 0.20-0.80 |
| Tantalum (Ta) | 0.05 max |
| Manganese (Mn) | 0.35 max |
| Silicon (Si) | 0.35 max |
| Carbon (C) | 0.08 max |
| Sulfur (S) | 0.015 max |
| Phosphorus (P) | 0.015 max |
| Copper (Cu) | 0.30 max |
Mechanical Properties of INCONEL® Alloy 718
INCONEL® alloy 718 offers exceptional mechanical properties suitable for high-stress applications:
| Property | Value |
|---|---|
| Tensile Strength | 965 MPa (140 ksi) min |
| Yield Strength (0.2% offset) | 550 MPa (80 ksi) min |
| Elongation | 30% min |
| Hardness (Rockwell C) | 36-42 |
| Density | 8.19 g/cm³ |
Performance at Different Temperatures
INCONEL® alloy 718 maintains its mechanical properties across a wide range of temperatures:
| Temperature Range | Performance |
|---|---|
| Room Temperature | High strength and corrosion resistance |
| Elevated Temperatures (up to 704°C / 1300°F) | Retains strength and oxidation resistance |
| Cryogenic Temperatures | Maintains toughness and ductility |
Corresponding Grades in Different Countries
INCONEL® alloy 718 is identified by various grades in different countries and regions:
| Country/Region | Grade |
|---|---|
| USA | UNS N07718 |
| Germany | 2.4668 |
| France | NC19FeNb |
| UK | – |
| Japan | – |
| China | GH4169 |
Standard Forms, Sizes, and Production Standards
Forms and Sizes
INCONEL® alloy 718 is available in various forms and sizes to meet industrial requirements:
| Form | Size Range |
|---|---|
| Sheets | Thickness: 0.5 mm – 50 mm |
| Plates | Thickness: 1 mm – 100 mm |
| Bars | Diameter: 6 mm – 300 mm |
| Wire | Diameter: 0.1 mm – 10 mm |
| Tubes | Outer Diameter: 3 mm – 200 mm |
| Pipes | Outer Diameter: 6 mm – 300 mm |
| Forgings | Various shapes and sizes as per standards |
Production Standards
INCONEL® alloy 718 conforms to international production standards:
| Standard | Description |
|---|---|
| ASTM B637 | Bars and rods |
| ASTM B670 | Sheets and plates |
| ASTM B673 | Seamless tubes |
| AMS 5662/AMS 5663 | Forgings |
| AWS A5.14 ERNiFeCr-2 | Welding wire |
Industry Applications of INCONEL® Alloy 718
INCONEL® alloy 718 is widely used in critical applications requiring high strength and corrosion resistance:
- Aerospace: Aircraft engine components, rocket motors, and spacecraft.
- Gas Turbines: Turbine discs, blades, and seals.
- Nuclear Reactors: Core components and reactor internals.
- Oil and Gas: Wellhead components, valves, and downhole tools.
- Automotive: Turbocharger rotors and seals.
Welding, Processing, Polishing, and Heat Treatment
INCONEL® alloy 718 can be welded using conventional methods such as gas tungsten arc welding (GTAW) and electron beam welding (EBW). It can also be brazed and soldered. For optimal performance, the alloy undergoes heat treatments such as solution annealing and age hardening.
Conclusion
INCONEL® alloy 718 stands as a premier nickel-based alloy offering unparalleled strength, corrosion resistance, and versatility across various industries. Its well-defined chemical composition, robust mechanical properties, adherence to international standards, and suitability for welding and heat treatment make it a preferred choice for applications in extreme environments. Engineers and designers seeking reliability and performance in high-stress applications can confidently select INCONEL® alloy 718 for their projects.
For detailed technical specifications and further inquiries, referencing specific product data sheets and consulting with manufacturers is recommended.
Welding, Machining, Polishing, Heat Treatment, and Cold Processing of INCONEL® Alloy 718
INCONEL® alloy 718 is renowned for its robust performance in various industrial applications, necessitating specific considerations for welding, machining, polishing, heat treatment, and cold processing. This section provides a detailed overview of these processes, highlighting key parameters and methods.
Welding of INCONEL® Alloy 718
Welding is crucial for fabricating components using INCONEL® alloy 718, ensuring structural integrity and performance under demanding conditions. The alloy exhibits good weldability with suitable techniques and precautions.
| Welding Method | Description |
|---|---|
| Gas Tungsten Arc Welding (GTAW) | Uses tungsten electrode to create the weld under inert gas atmosphere. Suitable for thin sections and precise welds. |
| Electron Beam Welding (EBW) | Utilizes high-energy electron beam for deep penetration welding. Ideal for thick sections and critical joints. |
| Resistance Welding | Applies pressure and electrical current to form welds. Suitable for sheet and wire applications. |
| Brazing and Soldering | Joins INCONEL® 718 components using filler materials at lower temperatures. Requires flux and controlled atmosphere. |
Machining of INCONEL® Alloy 718
Machining INCONEL® alloy 718 requires appropriate tools and techniques due to its high strength and work-hardening characteristics. Carbide tools and lubrication are typically used to achieve precise dimensions and surface finishes.
| Machining Process | Description |
|---|---|
| Turning | Rotates the workpiece against a stationary cutting tool to remove material and create cylindrical shapes. |
| Milling | Uses rotary cutters to remove material from the workpiece. Suitable for flat or contoured surfaces. |
| Drilling | Creates holes in the material using rotating drill bits. Requires low speeds and high feed rates. |
| Grinding | Achieves fine surface finishes using abrasive wheels. Useful for precision grinding and finishing. |
Polishing of INCONEL® Alloy 718
Polishing enhances the surface finish of INCONEL® alloy 718 components, improving aesthetics and corrosion resistance. Abrasive polishing compounds and techniques are employed to achieve desired smoothness and reflectivity.
| Polishing Technique | Description |
|---|---|
| Mechanical Polishing | Uses abrasive materials and rotating tools to remove surface imperfections and achieve smooth finishes. |
| Electrolytic Polishing | Electrochemical process that dissolves surface material to smooth and brighten the surface. |
| Chemical Polishing | Uses chemical solutions to selectively dissolve surface irregularities and enhance surface finish. |
Heat Treatment of INCONEL® Alloy 718
Heat treatment processes optimize the mechanical properties of INCONEL® alloy 718, enhancing strength, toughness, and resistance to stress corrosion cracking.
| Heat Treatment Process | Description |
|---|---|
| Solution Annealing | Heating to high temperatures followed by rapid cooling to homogenize the alloy and dissolve precipitates. |
| Age Hardening | Aging at intermediate temperatures to precipitate strengthening phases, increasing hardness and strength. |
| Stress Relieving | Heating to reduce residual stresses from welding or cold working. Improves dimensional stability and toughness. |
Cold Processing of INCONEL® Alloy 718
Cold processing techniques such as forming, bending, and drawing allow for shaping INCONEL® alloy 718 while maintaining its mechanical properties and corrosion resistance.
| Cold Processing Technique | Description |
|---|---|
| Forming | Bends or shapes the material using press brakes or roll forming machines. |
| Bending | Applies controlled force to achieve desired angles or curves. |
| Drawing | Pulls the material through dies to reduce diameter or form intricate shapes. |
| Cold Rolling | Reduces thickness and improves surface finish through repeated rolling processes. |
Conclusion
Understanding the welding, machining, polishing, heat treatment, and cold processing characteristics of INCONEL® alloy 718 is essential for maximizing its performance and longevity in industrial applications. By employing appropriate techniques and adhering to recommended practices, manufacturers and engineers can harness the full potential of this advanced nickel-based superalloy across various critical sectors.
For precise specifications and guidelines tailored to specific applications, consulting with material suppliers and referencing detailed technical data sheets is recommended.
This comprehensive introduction and detailed data sheet provide a thorough overview of INCONEL® alloy 718, emphasizing its chemical composition, mechanical properties, performance characteristics at different temperatures, applications, and advantages in demanding industrial environments across various countries.