Analysis of the Relationship between the Application Areas and Composition Content of Alloy 690

Alloy 690 is a high-performance nickel-based alloy widely used in critical equipment such as heat transfer tubes of steam generators in pressurized water reactor nuclear power plants due to its superior performance in high-temperature and highly corrosive environments. Its unique composition makes it outstanding in resisting intergranular corrosion and stress corrosion cracking, making it the preferred material for many demanding industrial applications.

The chemical composition of Alloy 690 mainly consists of nickel (approximately 58%) and chromium (27-31%). The high nickel content endows the alloy with excellent corrosion resistance, especially in harsh media such as chlorides and sulfides, effectively resisting pitting and crevice corrosion. Furthermore, nickel enhances the material’s toughness, allowing it to maintain stable mechanical properties at high temperatures. The increased chromium content further improves the alloy’s oxidation resistance, enabling it to form a stable oxide film in high-temperature environments, protecting the substrate from further oxidation and corrosion.

The alloy contains a small amount of iron (7-11%), which not only helps improve the material’s strength but also enhances its ductility in machining complex shapes. The presence of iron allows Alloy 690 to meet the stringent shape and dimensional requirements under complex industrial conditions. In contrast, the low carbon, silicon, and manganese content helps reduce the risk of intergranular corrosion, especially after welding. The controlled use of these elements ensures the material maintains good structural stability at high temperatures.

Thanks to these carefully designed compositional ratios, Alloy 690 is widely used in heat transfer tube materials for steam generators in pressurized water reactor nuclear power plants. The operating environment of steam generators is extremely harsh, requiring materials to maintain excellent corrosion resistance under long-term exposure to high temperatures, high pressures, and corrosive coolants. Alloy 690′s high chromium and high nickel content is designed to meet these challenges, ensuring structural integrity during long-term use and guaranteeing the safe operation of nuclear power plants.

Besides nuclear power plants, Alloy 690 is also used in other industrial fields requiring high temperature and corrosion resistance, such as chemical equipment, marine engineering, and high-temperature heating equipment. In these applications, Alloy 690 also demonstrates excellent corrosion and oxidation resistance, making it an indispensable material choice in engineering design.

In summary, the chemical composition of Alloy 690 is closely related to its application in highly corrosive and high-temperature environments. Through rational compositional design, it not only possesses excellent corrosion resistance but also exhibits superior mechanical properties and stability in complex industrial environments.