Mechanical properties and physical properties of Inconel 718
Inconel 718 alloy introduction
Inconel 718 alloy is a high-temperature alloy, which belongs to a type of nickel-based alloy. It is composed of nickel, chromium, iron, molybdenum, aluminum, titanium and other elements. Inconel 718 alloy has excellent high-temperature strength, corrosion resistance and oxidation resistance, which makes it widely used in aerospace, energy, chemical industry and automobile fields.
Inconel 718 alloy performs well in high-temperature environments and can maintain good strength and toughness in the temperature range of 600°C to 700°C. It has excellent oxidation resistance and can resist adverse environmental factors such as oxidation, corrosion and thermal fatigue. Inconel 718 alloy also has good machinability and weldability, and can be formed and processed by various common metal processing processes.
Due to its excellent performance, Inconel 718 alloy is widely used in the aerospace field, including jet engines, turbine blades, combustion chamber components and missile engines. It is also used in the energy industry, such as high-temperature and high-pressure environments in oil and gas extraction. Inconel 718 alloy is also commonly used in reactors, catalysts and corrosive media processing equipment in the chemical industry. In addition, in the fields of automobile manufacturing and aerospace, it is widely used in components such as brake systems, turbochargers and gas turbines.
The microstructural evolution and mechanical properties of Inconel 718 alloy are one of the key factors for its wide application. The following is an overview of the microstructural evolution and mechanical properties of Inconel 718 alloy:
Microstructural evolution: Inconel 718 alloy undergoes different stages of microstructural evolution during heat treatment. In the initial state, the alloy exists in the form of austenite (γ phase), which contains elements such as nickel, iron and chromium in solid solution. During the heating process, the alloy undergoes solid solution treatment, so that the solute elements in the alloy are uniformly dissolved in the austenite lattice. The structure of the solid solution is then fixed by rapid cooling (quenching). Finally, through solid solution aging treatment, strengthening precipitation phases such as γ' phase and γ'' phase are formed in the alloy, thereby improving the strength and hardness of the alloy.
Mechanical properties: Inconel 718 alloy has excellent mechanical properties, especially in high temperature environments. Here are some key mechanical properties:
High strength: Inconel 718 alloy still maintains high strength at high temperatures. This makes it ideal for high stress and high load conditions.
Good toughness: The alloy has good toughness, that is, it can resist cracking and breaking when subjected to impact or load.
Creep resistance: Inconel 718 alloy exhibits good creep resistance at high temperatures, that is, it can resist deformation and deformation under long-term exposure to high temperatures and harsh environmental conditions.
Fatigue resistance: The alloy has excellent fatigue resistance and can withstand cyclic loading and cyclic deformation without cracking.
Good corrosion resistance: Inconel 718 alloy exhibits good corrosion resistance in high temperature and corrosive environments, and has high resistance to oxidation and corrosion.
Inconel 718 aging and welding are two key aspects of processing and joining this high-strength, corrosion-resistant nickel-based superalloy. Aging is a heat treatment process, and welding involves joining different parts of the material together. The aging treatment and welding process of Inconel 718 are introduced below.
Aging treatment of Inconel 718:
Aging refers to the process of adjusting the lattice structure and properties of the alloy through heating and cooling. For Inconel 718, aging treatment mainly increases the strength of the alloy through precipitation hardening. Generally, the aging treatment of Inconel 718 includes the following steps:
Solution treatment: The alloy is heated to between 980°C and 1,050°C (1,800°F and 1,920°F) and maintained at this temperature for a period of time. This step will dissolve any precipitation and uniformly alloy.
Quenching: After solution treatment, the alloy is cooled to room temperature by rapid cooling, usually water quenching. This step prevents the reformation of undesirable phases while forming a supersaturated solid solution.
Aging: The quenched alloy is then heated to a temperature range of 720°C to 750°C (1,330°F to 1,380°F), held for several hours, and cooled in air. This allows the precipitation of the gamma-' and gamma-'' phases, which significantly enhance the strength of the alloy.
Solving Annealing and Age Hardening: Another common aging treatment is to heat the alloy to a temperature range of 900°C to 920°C (1,650°F to 1,690°F), followed by rapid cooling and subsequent aging. This provides a balance between strength and toughness.
Inconel 718 Welding:
Welding Inconel 718 requires careful consideration of the alloy's metallurgical properties to maintain its integrity and performance. Here are some important factors to consider when welding Inconel 718:
Pre-weld preparation: Proper cleaning and surface preparation are critical to remove impurities such as dirt, oil, or oxide layers that may affect the quality of the weld.
Welding methods: TIG welding (GTAW/TIG) and electron beam welding (EBW) are commonly used methods for welding Inconel 718 because they enable precise control of heat input. Inconel 718 is an excellent nickel-based superalloy with excellent properties and a wide range of applications. Here is a comparison of Inconel 718 with other alloys:
Inconel 718 vs. Inconel 625:
Strength: Inconel 718 has higher strength than Inconel 625, especially at high temperatures.
Heat resistance: Inconel 718 has better stability in high temperature environments and can withstand higher temperatures.
Corrosion resistance: Inconel 625 has better corrosion resistance in seawater and corrosive media, especially for acidic environments and chloride ions.
Processing performance: Inconel 625 is relatively easier to handle in terms of processing and welding.
Inconel 718 vs. Incoloy 825:
Strength: Inconel 718 has higher strength than Incoloy 825, especially at high temperatures.
Corrosion resistance: Incoloy 825 has better corrosion resistance in strong acid media such as sulfuric acid, hydrochloric acid, and phosphoric acid, while Inconel 718 has better corrosion resistance in high-temperature oxidizing environments.
Usage temperature range: Inconel 718 is suitable for high temperature and high stress environments, while Incoloy 825 is suitable for general industrial environments.
Inconel 718 vs. Hastelloy C276:
Corrosion resistance: Hastelloy C276 has better corrosion resistance in corrosive media such as strong acids, hydrochloric acid, and sulfuric acid, especially for some extreme corrosion conditions.
Oxidation resistance: Inconel 718 has better oxidation resistance in high-temperature oxidizing environments and is suitable for applications under high-temperature oxidizing conditions.
Processing performance: Inconel 718 is easier to handle in terms of processing and welding.
Overall, Inconel 718 is an excellent high-strength, heat-resistant, and corrosion-resistant alloy, particularly suitable for applications in high-temperature and high-stress environments. However, when selecting an alloy, the performance differences of various alloys need to be considered comprehensively based on the requirements of the specific application and the environmental conditions.
Welding methods, such as laser welding and plasma arc welding, can also be used.
The supply form and product specifications of Inconel 718 will vary depending on the specific manufacturer and supplier. Here are some common Inconel 718 supply forms and product specifications:
Supply Form:
Plate/Sheet: Inconel 718 plates and sheets are available in various sizes and thicknesses.
Tube/Pipe: Inconel 718 tubes and pipes are available in various specifications and can be seamless or welded.
Rod/Bar: Inconel 718 rods and bars are available in different diameters and lengths.
Wire/Wire: Inconel 718 wire and wire are available in different diameters for a variety of welding and fabrication applications.
Forgings: Inconel 718 forgings are available in various shapes and sizes, such as discs, shafts and rings.
Parts and Components: Inconel 718 parts and components are available as per customer requirements.
Product Specifications:
Chemical Composition: The chemical composition of Inconel 718 generally complies with relevant standards and specifications, such as ASTM B637 and AMS 5662.
Mechanical Properties: The mechanical properties of Inconel 718 include tensile strength, yield strength, elongation and hardness.
Corrosion Resistance: The corrosion resistance of Inconel 718 involves its corrosion resistance in different media, such as acid, alkali, salt and oxidizing environments.
Dimensions and Dimensional Tolerances: Inconel 718 products are available in different sizes and dimensional tolerances, depending on customer needs and product specifications.
Surface Treatment: Inconel 718 products may require surface treatment, such as polishing, pickling or heat treatment.
Please note that the specific product specifications and supply forms should be determined according to the supplier's catalog, specification sheet or communication with the supplier. Different manufacturers and suppliers may provide different supply forms and product specifications, so it is recommended to contact the relevant suppliers for accurate information according to specific needs.
