How high temperature can Inconel 718 plate withstand?
Analysis of high temperature resistance and application technology of Inconel 718 plate
Inconel 718 is a high-performance nickel-based high-temperature alloy. Due to its excellent high temperature resistance, corrosion resistance and high strength, it is widely used in aerospace, energy, chemical industry and other fields. This article will comprehensively analyze the high temperature resistance and application of Inconel 718 plate from the aspects of technical parameters, industry standards, material selection misunderstandings and technical disputes.
1. Technical parameters of Inconel 718 plate
Inconel 718 is a precipitation hardened nickel-chromium alloy, whose chemical composition mainly includes elements such as nickel (Ni), chromium (Cr), molybdenum (Mo) and niobium (Nb). This alloy performs well in high temperature environments, and its main technical parameters are as follows:
High temperature performance: The maximum operating temperature that Inconel 718 can withstand under normal pressure is 650℃, which can be slightly increased to 700℃ under certain special conditions (such as vacuum environment). This property makes it an ideal choice for equipment such as high-temperature gas turbines, rocket engines, and high-temperature reactors.
Creep resistance: In long-term high-temperature use, Inconel 718 has excellent creep resistance and can work for a long time at 600°C without significant deformation. This makes it widely used in aerospace engine blades and high-temperature pipelines.
Anti-oxidation performance: Inconel 718 performs well in high-temperature oxidation environments, and its oxide film is dense and stable, which can effectively prevent oxidation in environments below 1000°C.
Mechanical properties: At room temperature, the tensile strength of Inconel 718 can reach more than 1000 MPa and the yield strength is about 850 MPa. Even in high-temperature environments, its strength can still be maintained at a high level.
2. Industry standards and specifications
When selecting and using Inconel 718 plates, relevant industry standards and specifications must be followed to ensure that the material properties meet the actual application requirements.
ASTM standard: ASTM B928 is the main ASTM standard for Inconel 718, which specifies the chemical composition, heat treatment requirements and mechanical properties of the alloy. For example, the standard requires that the nickel content of Inconel 718 is not less than 58% and the chromium content is not less than 16%.
AMS standard: AMS 5643 is the AMS standard for Inconel 718, which is mainly applicable to the aerospace field. This standard imposes strict requirements on the heat treatment, surface treatment and non-destructive testing of materials.
National standard reference: In China, the performance indicators of Inconel 718 can refer to the GB/T 3620 "Nickel-Chromium Alloy Bar" standard, which clearly stipulates the chemical composition and mechanical properties of the material.
3. Material selection misunderstandings
When selecting Inconel 718 plates, avoid the following common misunderstandings:
Focus only on high temperature performance: Although Inconel 718 has excellent high temperature performance, its toughness and processing performance may not be as good as other materials (such as austenitic stainless steel) in low temperature environments. Therefore, the temperature range of the use environment should be considered comprehensively when selecting materials.
Ignore surface treatment: The surface state of Inconel 718 has a great influence on its performance. For example, plates that have not been surface treated may produce an oxide film at high temperatures, affecting its corrosion resistance. Therefore, when selecting materials, pay attention to the surface treatment process.
Blindly pursue high costs: Inconel 718 has a high cost, but not all high temperature application scenarios require the use of this material. When selecting materials, an economic evaluation should be conducted based on specific needs to avoid unnecessary cost waste.
4. Technical controversy: Hot working performance of Inconel 718
The hot working performance of Inconel 718 is a controversial technical issue. Although the alloy has good processing properties at high temperatures, its processing properties may drop significantly in certain specific temperature ranges (such as 900-1000℃). This is because Inconel 718 undergoes secondary precipitation in this temperature range, causing the material to become hard and difficult to process. Therefore, during hot processing, the heating temperature and cooling rate must be strictly controlled to avoid performance loss.
V. Domestic and foreign market data
The market price of Inconel 718 is greatly affected by global nickel price fluctuations. According to data from the London Metal Exchange (LME) and Shanghai Nonferrous Network, at the beginning of 2023, the global nickel price was about US$20,000/ton, while the market price of Inconel 718 was about US$50-70/kg. In the domestic market, data from Shanghai Nonferrous Network showed that the price fluctuations of Inconel 718 were highly correlated with the international nickel price, but were generally 5-10% higher than the international price.
VI. Summary
Inconel 718 plate has become an important material in the field of high temperature engineering due to its excellent high temperature resistance, corrosion resistance and high strength. In the process of material selection and use, it is necessary to avoid common misunderstandings and pay attention to the technical controversial points of its hot processing performance. Combined with domestic and foreign market data, reasonable material cost evaluation is carried out to ensure the balance between material performance and economy.
Through the analysis of this article, it is hoped that it will provide valuable reference for material engineers and practitioners in related industries to help them better understand and apply Inconel 718 plate.
