316L Stainless Steel Properties And Uses

  • 3:51 am

316L stainless steel properties and uses

Due to its excellent corrosion resistance, 316L stainless steel has a wide range of applications in the chemical industry. 316L is also a derivative of 18-8 type austenitic stainless steel with 2-3% Mo added. Many steel grades are also derived based on 316L. For example, 316Ti is derived after adding a small amount of Ti, 316N is derived after adding a small amount of N, and 317L is derived by increasing the Ni and Mo content. 

Most of the existing 316Ls on the market are manufactured according to the American Standard. For cost reasons, steel mills usually try to reduce the Ni content of their products to a lower limit. The American standard stipulates that the Ni content of 316L is 10-14%, while the Japanese standard stipulates that the Ni content of 316L is 12-15%. According to the minimum standard, there is a 2% difference in Ni content between the American standard and the Japanese standard, which is quite large in price, so when purchasing a 316L product, make sure that the product refers to it clearly. need to do it. Compliant with ASTM or JIS standards.

With a Mo content of 316L, this steel has excellent pitting corrosion resistance and can be safely used in environments containing Cl- and other halogen ions. Since 316L is used primarily due to its chemical nature, steel mills have slightly lower 316L surface inspection requirements (compared to 304), and customers with higher surface requirements need to enhance surface inspection.

Use of 316L stainless steel: seawater, chemicals, dyes, paper, oxalic acid, fertilizers, and other production equipment; photo, food industry, coastal facilities, ropes, CD rods, bolts, and nuts.

Chemical Composition

316L stainless steel is an austenitic stainless steel that primarily consists of iron, with a significant amount of chromium and nickel. Its typical composition includes:

  • Chromium (Cr): 16-18%
  • Nickel (Ni): 10-14%
  • Molybdenum (Mo): 2-3% (this enhances its corrosion resistance)
  • Carbon (C): ≤ 0.03%
  • Manganese (Mn): ≤ 2%
  • Silicon (Si): ≤ 0.75%
  • Phosphorus (P): ≤ 0.045%
  • Sulfur (S): ≤ 0.03%

3. Key Properties

316L stainless steel offers several critical properties that make it suitable for a wide range of applications:

  • Corrosion Resistance:
    • 316L is highly resistant to corrosion, particularly in chloride environments, making it ideal for marine and chemical applications. The addition of molybdenum enhances its resistance to pitting and crevice corrosion.
  • Weldability:
    • The low carbon content reduces the risk of carbide precipitation during welding, which makes 316L stainless steel easier to weld compared to 316. This property is crucial for applications requiring high structural integrity after welding.
  • High Temperature Resistance:
    • 316L stainless steel maintains its strength and corrosion resistance even at elevated temperatures. It is commonly used in applications where exposure to high temperatures is frequent.
  • Mechanical Properties:
    • Tensile Strength: Typically around 485 MPa (70,000 psi)
    • Yield Strength: Approximately 170 MPa (25,000 psi)
    • Elongation: 40% (in 2 inches)
    • Hardness: The Rockwell B hardness is typically around 95.
  • Non-Magnetic:
    • Like most austenitic stainless steels, 316L is non-magnetic, which is beneficial in applications where magnetism could be an issue.

4. Applications of 316L Stainless Steel

316L stainless steel’s properties make it suitable for a wide range of applications across various industries:

  • Marine Applications:
    • Due to its excellent corrosion resistance in seawater, 316L is widely used in marine environments for components such as boat fittings, valves, and pumps.
  • Chemical Processing:
    • In chemical processing plants, 316L is used for tanks, pipes, heat exchangers, and other equipment that must resist corrosion from harsh chemicals.
  • Medical Devices:
    • 316L stainless steel is biocompatible, making it a popular choice for surgical instruments, implants, and other medical devices. It is also used in the manufacture of pharmaceutical processing equipment.
  • Food and Beverage Industry:
    • 316L is used in food processing and brewing equipment due to its ability to resist corrosion from acids and other chemicals found in food and beverages.
  • Pharmaceutical Industry:
    • The material’s resistance to chemical corrosion and ease of cleaning make it ideal for pharmaceutical equipment, where maintaining high levels of hygiene is crucial.
  • Architecture and Construction:
    • In construction, 316L stainless steel is used for facades, handrails, and other architectural elements that require both aesthetic appeal and resistance to corrosion, especially in coastal areas.

5. Advantages and Limitations

  • Advantages:
    • Excellent corrosion resistance, particularly in chloride environments.
    • High temperature resistance and good mechanical properties.
    • Weldability without risk of intergranular corrosion.
    • Non-magnetic, making it suitable for specific applications.
  • Limitations:
    • Higher cost compared to 304 stainless steel.
    • Although it is resistant to a wide range of chemicals, it may still be susceptible to stress corrosion cracking in certain conditions.

Conclusion

316L stainless steel is a versatile, corrosion-resistant material used in many industries, including marine, chemical processing, medical devices, and construction. Its combination of properties—such as resistance to corrosion, good mechanical performance, and ease of welding—makes it a preferred choice for applications where durability and reliability are paramount.