What is the difference between stainless steel 304 and 304L

What is the difference between stainless steel 304 and 304L

Stainless steel valve performance and scope of application

304 stainless steel performance introduction

304 stainless steel is the most common steel grade, as a widely used steel, it has good corrosion resistance, heat resistance, low temperature strength and mechanical properties; Good hot workability such as stamping and bending, no heat treatment hardening phenomenon (non-magnetic, use temperature -196 °C ~ 800 °C) .

304 stainless steel scope of application

Houseware (Class 1 and 2 tableware, cabinets, indoor plumbing, water heaters, boilers, bathtubs)

Auto parts (windshield wipers, mufflers, moldings)

Medical appliances, building materials, chemicals, food industry, agriculture, ship parts

304L stainless steel (L is low carbon) performance introduction

As a low-carbon 304 steel, its corrosion resistance is similar to that of 304 steel in the general state, but after welding or stress relief, its resistance to grain boundary corrosion is excellent; In the absence of heat treatment, it can also maintain good corrosion resistance, and the use temperature is -196 °C ~ 800 °C.

What is the difference between stainless steel 304 and 304L


In this detailed guide, we’ll explore the differences between stainless steel 304 and 304L for more info visit here.

1. Chemical Composition:

Stainless Steel 304:

  • Carbon Content: Stainless-steel 304 contains a maximum of 0.08% carbon.
  • Chromium Content: It contains 18-20% chromium.
  • Nickel Content: Stainless steel 304 contains 8-10.5% nickel.
  • Other Elements: It may contain small amounts of manganese, silicon, sulfur, and phosphorus.

Stainless Steel 304L:

  • Carbon Content: Stainless-steel 304L is a low carbon variant and contains a maximum of 0.03% carbon.
  • Chromium Content: Like 304, it contains 18-20% chromium.
  • Nickel Content: It contains 8-12% nickel.
  • Other Elements: Similar to 304, it may contain trace amounts of manganese, silicon, sulfur, and phosphorus.

2. Corrosion Resistance:

Both stainless-steel 304 and 304L exhibit excellent corrosion resistance, making them suitable for a wide range of applications, especially in environments where exposure to moisture, chemicals, and corrosive substances is a concern. The chromium content in these alloys forms a passive oxide layer on the surface, preventing further corrosion.

3. Weldability:

Stainless Steel 304:

  • Stainless steel 304 can be welded using standard welding techniques, such as TIG (Tungsten Inert Gas) or MIG (Metal Inert Gas) welding.
  • However, during welding, it can be susceptible to sensitization, which is the formation of chromium carbides at the grain boundaries, reducing corrosion resistance.
  • To mitigate sensitization, post-weld annealing or the use of a low-carbon variant like 304L is recommended.

Stainless Steel 304L:

  • Stainless-steel 304L is a low-carbon variant designed to minimize sensitization during welding.
  • It offers improved weldability compared to 304, making it a preferred choice for applications where welding is a critical process.
  • Due to its lower carbon content, 304L is less prone to carbide precipitation at the grain boundaries.

4. Applications:

Stainless Steel 304:

  • Stainless steel 304 is commonly used in a wide range of applications, including:
    • Kitchen appliances and cookware
    • Architectural and structural components
    • Automotive parts
    • Chemical processing equipment
    • Food and beverage industry equipment
    • Pharmaceutical industry equipment
    • Piping and tubing

Stainless Steel 304L:

  • Stainless-steel 304L is often preferred in applications where weldability and corrosion resistance are critical, such as:
    • Welded components in chemical processing
    • Pharmaceutical and biotechnology equipment
    • Heat exchangers
    • Piping systems for corrosive fluids
    • Industrial and commercial kitchen equipment

5. Strength and Durability:

Both 304 and 304L stainless-steel have similar mechanical properties, including high tensile strength and good toughness. They are known for their durability and longevity in various applications.

6. Cost Considerations:

Stainless steel 304L, being a low-carbon variant, is slightly more expensive than 304 due to the additional refining process required to reduce the carbon content. However, the cost difference is generally minimal and often outweighed by the benefits of improved weldability and corrosion resistance in critical applications.

7. Heat Resistance:

Both 304 and 304L have good heat resistance and can withstand elevated temperatures. They are often used in applications involving exposure to moderately high temperatures, such as cooking equipment and exhaust systems.

8. Magnetic Properties:

Both 304 and 304L stainless-steel are non-magnetic in their annealed (heat-treated) state. This property makes them suitable for use in applications where magnetism is undesirable, such as in electronic equipment.

9. Machinability:

Stainless steel 304 and 304L are generally considered to have good machinability. They can be easily cut, formed, and machined using standard machine tools and techniques.

10. Summary:

In summary, while Stainless steel 304 and 304L share many similarities, the key difference lies in their carbon content. Stainless steel 304 has a slightly higher carbon content, while 304L is a low-carbon variant. This low-carbon content makes 304L more weldable and less susceptible to sensitization during welding. Therefore, the choice between 304 and 304L should be based on the specific requirements of your application, with 304L being the preferred option for welding-intensive projects or those involving exposure to corrosive environments where sensitization is a concern. Ultimately, both grades offer excellent corrosion resistance and durability, making them valuable materials in a wide range of industries.



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