Stainless Steel 316N (UNS S31651)
Stainless Steel 316N (UNS S31651) is a nitrogen-enhanced version of Type 316 stainless steel used for applications that require high strength and excellent corrosion resistance. It features the same general characteristics of 316 stainless steel but with a higher nitrogen content which gives it enhanced strength and resistance to intergranular corrosion. This austenitic stainless steel offers superior toughness and ductility compared to standard 316 stainless steel and is often used in pressure vessels and pipelines operating at elevated temperatures where long service life is expected.
Chemical Composition
Stainless Steel 316N is composed of approximately 17-20% chromium, 12-15% nickel, 2-3% molybdenum and 2% nitrogen with small amounts of manganese, silicon and phosphorus. Using Nitrogen as an alloying agent increases the corrosion resistance and strength of 316N stainless steel compared to standard Type 316.
Physical Properties
Stainless Steel 316N resists corrosion due to its high chromium, nickel and molybdenum content, making it highly corrosion resistant. It has a much higher degree of resistance to airborne corrosive compounds when compared with conventional steel, providing high resistance to pitting and crevice corrosion in halide environments and eliminating the need for periodic passivation even in severely corrosive environments.
Stainless Steel 316N exhibits good strength and ductility rates when compared to other stainless steel alloys and is typically used in applications where parts has to withstand elevated temperatures, pressure, chemicals and marine environment. The physical properties of 316N can be seen in the following table.
Mechanical, Thermal and Electrical Properties
Stainless Steel 316N exhibits superior mechanical characteristics such as high ductility and toughness compared to other austenitic stainless steel alloys. It also offers good electrical resistivity and heat resistance which makes it suitable for use in electrical systems and components. The thermal properties of 316N are quite excellent and offers the alloy enhanced resistance to oxidation at elevated temperatures.
Applications
Stainless Steel 316N is primarily used in applications that require corrosion resistance, increased strength, and toughness at elevated temperature. It is commonly found in pressure vessels, food processing equipment,offshore drillings and marine environments. It is also used in power generation turbines and aircraft components as well.
Stainless Steel 316N is often used in applications where traditional mild steel or stainless steel cannot provide the desired levels of corrosion and strength. Its exceptional corrosion resistance, resistance to general and localized corrosion, makes it ideal for the construction of pipelines and applications in offshore, chemical and petrochemical industries.
Conclusion
Stainless Steel 316N (UNS S31651) is an austenitic stainless steel grade which has been nitrogen-enhanced to provide increased strength and corrosion resistance compared to Type 316. Its high Ni, Cr and Mo content gives it excellent corrosion resistance, resistance to pitting and crevice corrosion as well. It can also withstand high temperatures, pressure and is highly resistant to caulking and cracking. Due to its excellent properties, this grade of stainless steel is used in a wide variety of applications, including food processing equipment, pressure vessels, offshore drilling, power generation turbines and aircraft components.
