Comparing 304 vs 304L Stainless Steel: Key Differences and Applications

Stainless steel is valued for its corrosion resistance and high-temperature durability. However, similar names can create confusion when differentiating between subcategories like 304 and 304L. The primary distinction lies in carbon content: 304 has up to 0.08%, while 304L has a maximum of 0.03%. This minor change leads to notable differences in their characteristics.

In this blog, we will explore the differences between 304 stainless steel and its variant 304L, focusing on their properties, applications, and other distinguishing factors.

What is 304 Stainless Steel?

304 stainless steel, or A2, 18/8, has 18% chromium and 8% nickel, offering good corrosion resistance, formability, and durability. Heat treatment cannot harden it and is used in the annealed state. It’s weldable, machinable, and commonly used for sinks, food tanks, surgical tools, and exhaust systems.

What is 304L Stainless Steel?

304L stainless steel is a solid, silver-gray alloy made of 70% iron, 18% chromium, and 8% nickel. “L” stands for “Low carbon,” with 0.03% carbon, lower than 304. This prevents carbide buildup during welding and boosts corrosion resistance. It works well in corrosive environments without annealing. This substance is primarily utilized in sectors such as chemical processing, food and drink manufacturing, and building.

Difference Properties Between 304l vs 304 Stainless Steel 

The main difference between 304 and 304L stainless steel lies in the carbon content. But the other factors also set them apart. This part will explore these differences, including their properties, applications, and production processes, to help you choose the right one.

Chemical Composition of 304 vs 304L (by Weight%)

Corrosion Resistance

304 and 304L have nearly identical corrosion resistance in most environments. However, 304L’s lower carbon content provides better protection against intergranular corrosion, especially after welding or heat exposure.

Weldability

304L offers better weldability than 304. It does not require post-weld annealing, reducing the risk of weld-area corrosion, whereas 304 may need annealing to maintain corrosion resistance after welding.

Physical Property of 304 vs 304L

Density

Both 304 and 304L stainless steels have a density of 8.0 g/cm³, indicating they have the same weight per unit volume, making them equally suitable for applications where weight is a consideration.

Melting Point

Their melting point ranges from 1400°C to 1450°C, enabling both materials to perform well at high temperatures without losing structural integrity.

Thermal Conductivity and Modulus of Elasticity

The thermal conductivity for both is 16.2 W/m·K at 100°C, meaning they transfer heat at the same rate. Additionally, their modulus of elasticity is 193 GPa, giving both the same stiffness and ability to return to their original shape after deformation.

Mechanical Properties of 304 vs 304L

The higher yield and tensile strength of 304 stainless steel make it ideal for demanding applications like structural components and heavy-duty equipment. It offers superior durability under stress. In comparison, a 304 component is less likely to deform or break under load than a 304L one, which is more prone to deformation due to its lower strength.

Why Use 304L Stainless Steel?

304L is used despite its lower strength because it resists intergranular corrosion better, especially after welding. Its low carbon content prevents carbide precipitation, making it ideal for welded parts without needing post-weld annealing, even though 304 is stronger.

Manufacturing Processing of 304 and 304L

304 and 304L stainless steels are produced similarly, but their carbon content difference affects certain manufacturing steps, particularly in welding and corrosion resistance. Grasping these procedures is essential for choosing the correct grade.

Welding

304: Needs precise regulation of heat input to prevent carbide formation, which may cause corrosion in welded regions. Post-weld annealing is frequently required to regain corrosion resistance.

304L: Because of its reduced carbon content, 304L is less susceptible to carbide formation during welding. This allows it to be welded without the need for post-weld annealing, making it more convenient for welding applications.

Heat Treatment

304: May require annealing after forming or welding to reduce internal stresses and restore corrosion resistance.

304L: Typically does not require annealing after welding due to its lower carbon content, which reduces the risk of sensitization.

Machinability

304: Slightly harder and more prone to work hardening compared to 304L, which can affect machining speed and tool wear.

304L: Easier to machine than 304, with less work hardening, making it more suitable for complex machining operations.

In summary, the manufacturing processes for 304 and 304L are mostly similar, especially in material properties, processing methods, and applications. However, they differ in welding performance, heat treatment, and machining. Selecting the appropriate material relies on the particular requirements of the application.

Cost of 304 vs 304L

The cost difference between 304 and 304L stainless steel is usually small. However, 304L is slightly more expensive due to the additional processing required to improve weldability and resistance to intergranular corrosion, especially in welded structures. Despite the slight price increase, the long-term advantages of 304L in certain environments can offset the higher initial cost.

Equivalent Grades of 304 and 304L

Please refer to our table of equivalent grades of 304 and 304L stainless steel in accordance with the relevant national and international standards.

Other Subgrades of 304 Stainless Steel

304 stainless steel includes various subgrades that provide distinct characteristics for diverse uses. These subgrades include 304H and 304N, each tailored for unique requirements in various industries.

304H

This subgrade contains more carbon than standard 304, enhancing its strength at high temperatures and resistance to oxidation. It’s commonly used in applications like power generation and chemical processing where elevated temperatures are a concern.

304N

Known for its enhanced strength due to added nitrogen, 304N offers better mechanical properties and corrosion resistance than standard 304. It’s often used in high-strength structural applications and critical components where improved performance is needed.

Application of 304 vs 304L Stainless Steel

Although 304 and 304L stainless steels share similar chemical and physical properties, their differing carbon content leads to variations in their applications. These differences influence where each grade is most effectively used.

Applications of 304 Stainless Steel

• Structural Components: Used in building frameworks, bridges, and load-bearing structures.
• Automotive Parts: Common in exhaust systems, engine components, and trim.
  Industrial Equipment: Ideal for tanks, pipelines, and machinery exposed to various chemicals.
• Consumer Products: Found in kitchen sinks, cookware, and home appliances.
  Medical Devices: Utilized in surgical instruments, dental tools, and hospital equipment.
• Food Processing Equipment: Used in food storage, handling, and preparation equipment, such as containers, utensils, and conveyor systems.

Applications of 304L Stainless Steel

• Welded Structures: Preferred in welded pipelines, storage tanks, and heat exchangers.
  Chemical Processing: Used in equipment that handles corrosive chemicals, like reactors and mixing tanks.
• Marine Environments: Suitable for shipbuilding, offshore platforms, and underwater piping.
• Pharmaceutical Equipment: Applied in drug manufacturing equipment where purity is critical.
• Food Processing: Ideal for handling acidic foods and beverages, such as fermentation tanks and food storage units.

Common Applications for Both 304 and 304L

• Architectural Elements: Used in cladding, handrails, and decorative facades.
• Heat Exchangers: Employed in systems for power generation and HVAC.
• Pressure Vessels: Found in boilers, gas cylinders, and industrial pressure containers.
• Piping Systems: Used in water treatment plants, oil refineries, and distribution systems.
• Food and Beverage Equipment: Common in brewing, dairy processing, and cooking appliances.

In summary, 304 is best for high-strength applications like structural components, while 304L is ideal for welding and corrosive environments. Both are widely used in architecture, food processing, and piping systems due to their shared properties.

Is 304L Harder than 304?

No, 304L is not harder than 304. 304L has slightly lower tensile and yield strength compared to 304 due to its lower carbon content.

What is the Difference Between 304 and 304L Dual Certified?

Dual-certified 304/304L stainless steel meets the specifications for both grades. It has the chemical composition of 304L but meets the mechanical properties of 304.

How Strong is 304 Stainless Steel?

304 Stainless Steel has a tensile strength of around 515 MPa (75 ksi) and a yield strength of about 215 MPa (31 ksi). This strength makes it suitable for various structural applications, as it can withstand significant stress and pressure without deforming, while also offering good ductility and toughness.

What Is 304 Stainless Steel Made of?

304 Stainless Steel is composed of 18-20% chromium and 8-10.5% nickel, along with small amounts of carbon, manganese, silicon, and other elements. This specific blend gives it excellent corrosion resistance, formability, and overall durability, making it one of the most widely used stainless steels.

Summary and Conclusion

304 and 304L stainless steels are both corrosion-resistant and versatile. The main difference is carbon content: 304 has up to 0.08%, while 304L has up to 0.03%. This makes 304L better for welding and corrosive environments, though it’s slightly weaker.

304 is best for high-strength uses, while 304L is ideal for welding and corrosion resistance. Both are commonly used in architecture, food processing, and piping.

SteelPRO Group offers a large inventory of 304 and 304L stainless steel in plates, pipes, and round bars. For other stainless steel grades, visit our blog page. Contact our experts for the best quotes!