SUS321 is a titanium-stabilized austenitic chromium-nickel stainless steel designed to provide a modified Type 18-8 alloy with superior resistance to intergranular corrosion. The stainless steel is favored for its stability and corrosion resistance in high-temperature environments, making it ideal for many specific applications.
SUS321 achieves the stabilization of the austenite structure by adding titanium. Titanium has a higher affinity for carbon than chromium, so the titanium carbides formed within the grains are more random rather than forming a continuous pattern at the grain boundaries. This special microstructure helps to improve the resistance to intergranular corrosion, making SUS321 ideal for use in high-temperature environments.
Compared with traditional 18-8 alloys, SUS321 has better performance in intergranular corrosion. Intergranular corrosion is usually a corrosion phenomenon at the boundary of metal grains at high temperatures, which reduces the corrosion resistance of the material. By introducing titanium, SUS321 successfully inhibits the corrosion of grain boundaries in high-temperature environments, thereby improving its service life in complex corrosive environments.
The SUS321 excels in applications that require intermittent heating between 800F (427C) and 1650F (899C). Its resistance to intergranular corrosion makes it the preferred material for high-temperature fields such as petrochemical and chemical industries. Whether it is a piping system, a heat exchanger or a high-temperature reactor, the SUS321 can robustly cope with high-temperature and high-pressure environments and ensure the stability of the system for long-term operation.
The chemistry of SUS321 has been carefully formulated to ensure stable performance at high temperatures. The rational ratio of key elements, such as low carbon content, moderate manganese content, nickel addition, etc., provides excellent mechanical properties and corrosion resistance. In addition, the addition of titanium not only stabilizes the austenite structure, but also improves the heat resistance of the overall material.
Carbon (maximum):
Phosphorus (maximum):
Silicon (maximum):
Nickel (nominal):
Titanium (nominal):5x c minimum.
Manganese (maximum):
Sulphur (maximum):
Chromium (nominal):
Iron (nominal):Balance.
SUS321 is widely used in petrochemical, chemical, pharmaceutical and other industries, especially in high-temperature, high-pressure, and corrosive environments. Its excellent resistance to intergranular corrosion makes it excellent in corrosive media such as sulfuric acid and acidic solutions. When manufacturing critical equipment such as precision instruments, heat exchangers, and piping systems, engineers prefer the SUS321 to ensure long life and efficient operation.
SUS321 stainless steel is an ideal material for many high-temperature applications due to its stability in high-temperature environments and resistance to intergranular corrosion. The optimization of its chemical composition and the stabilizing effect of titanium make it excellent in complex corrosive environments. With the continuous improvement of industrial requirements for material performance, SUS321 will surely show its unique value in more fields in the future.
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