304 vs 304L Stainless Steel: How to Choose

Choosing between 304 and 304L can feel confusing. The wrong choice  can trigger weld failures, surface corrosion, tolerance shifts after machining, and unnecessary production costs. These problems disrupt timelines and create quality risks. You can avoid these issues by reading this article.

304 vs 304L stainless steel often confuses engineers, so this guide explains every key factor you need to choose correctly. You will learn the difference between 304 and 304L, including 304 vs 304L chemical composition, corrosion behavior, strength, CNC performance, weld response, applications, and the real 304 vs 304L price difference. These insights help you avoid production errors and select the right alloy with confidence.

What Is 304 Stainless Steel?

304 stainless steel is an austenitic chromium nickel alloy defined by AISI 304 and SAE 304 standards. It belongs to the 18/8 steel family and is recognized for its stable structure, good corrosion resistance, and reliable performance in general industrial use. It is widely used because its composition and behavior remain consistent across global manufacturing systems.

What Is 304L Stainless Steel?

304L stainless steel is a low-carbon variant of 304, defined by AISI 304L and SAE 304L standards. Its reduced carbon content minimizes sensitization during welding, which prevents intergranular corrosion. Engineers often select it for welded assemblies and parts that need long-term corrosion resistance while maintaining the austenitic structure of standard 304.

304 vs 304L Stainless Steel: Equivalent Materials

304 vs 304L stainless steel has multiple names and equivalents across global standards.The following table lists the common equivalents of 304 and 304L stainless steel in different regions and standards, making it easier to identify the correct alloy for your project.

Region / Standard	304 Equivalent	304L Equivalent
Europe (EN)	1.4301, X5CrNi18-10	1.4307, X2CrNi18-9
Japan (JIS)	SUS304	SUS304L
USA (UNS)	S30400	S30403
China (GB)	06Cr19Ni10	06Cr19Ni10L
Russia (GOST)	08Х18Н10	08Х18Н10Л
Australia	304S15	304LS15

304 vs 304L Stainless Steel: Chemical Composition

The difference between 304 and 304L stainless steel mainly lies in carbon content. 304 contains up to 0.08% carbon, while 304L keeps it below 0.03%. Both grades have similar chromium and nickel levels, giving good corrosion resistance and CNC machinability. The following table shows the chemical composition of 304 and 304L.

Element	304	304L
Carbon (C)	≤0.08%	≤0.03%
Chromium (Cr)	18–20%	18–20%
Nickel (Ni)	8–10.5%	8–10.5%
Manganese (Mn)	≤2%	≤2%
Silicon (Si)	≤1%	≤1%
Phosphorus (P)	≤0.045%	≤0.045%
Sulfur (S)	≤0.03%	≤0.03%
Nitrogen (N)	≤0.1%	≤0.1%
Iron (Fe)	Balance	Balance

304 vs 304L Stainless Steel: Mechanical Properties

In terms of 304 vs 304L strength, 304 has higher tensile and yield strength than 304L. This makes 304 better for structural parts that must bear higher loads or resist deformation during CNC machining. 304L’s lower strength is offset by its superior weldability and reduced risk of sensitization, making it ideal for welded assemblies. Both grades have the same elongation and hardness, ensuring reliable formability and impact resistance. Choosing between them depends on whether load-bearing capacity or welding performance is more critical for your part.

The following table shows key mechanical properties of 304 vs 304L:

Property	304 Stainless Steel	304L Stainless Steel
Tensile Strength	515 MPa	485 MPa
Yield Strength	205 MPa	170 MPa
Elongation at Break	40%	40%
Hardness (Rockwell B)	82	82
Impact Toughness	High	High

304 vs 304L Stainless Steel: Physical Properties

Both 304 vs 304L stainless steel share very similar physical properties, which makes them predictable during CNC machining and industrial applications.The following table lists the key physical properties of 304 and 304L, including density, thermal conductivity, thermal expansion, melting point, and electrical resistivity.

Property	304 Stainless Steel	304L Stainless Steel
Density	8.0 g/cm³	8.0 g/cm³
Thermal Conductivity	16.2 W/m·K	16.2 W/m·K
Thermal Expansion	17.2 µm/m·°C	17.3 µm/m·°C
Melting Point	1400–1450°C	1400–1450°C
Electrical Resistivity	0.72 µΩ·m	0.72 µΩ·m

304 vs 304L Stainless Steel: Fabrication & Processing Properties

This chapter describes how the two grades, 304 and 304L stainless steel, behave during key fabrication and processing steps. It covers their performance in CNC machining, cold and hot working, heat treatment, welding, forming, and annealing.

CNC Machining

304 vs 304L machinability is similar, but 304 is slightly harder due to higher carbon content. It cuts cleanly with sharp tools on 4- and 5-axis CNC centers, maintaining tight tolerances. 304L is easier on tools during long runs but may need slower feeds for optimal surface finish.

When machining stainless steels like 304, 304L, and similar austenitic alloys, VMT’s CNC secrets include optimizing cutting speed and feed rates for each grade, controlling tool paths to prevent surface scratches, and applying intermediate annealing when necessary. These methods ensure iPhone-level appearance and atomic clock-level precision. For more detailed machining secrets, please contact VMT.

Cold Working

Both alloys respond well to cold forming. 304 provides slightly higher strength after work hardening, while 304L remains more ductile. For precision bends or stamped parts, 304L reduces the risk of cracking in welded assemblies.

Hot Working

304 and 304L can be hot worked at high temperatures without significant grain growth. 304L’s lower carbon helps prevent sensitization during heat, making it safer for post-weld forming.

Heat Treatment

Neither 304 nor 304L benefits from conventional heat hardening. Annealing restores ductility after cold working. 304L anneals slightly faster due to its lower carbon content, preserving weld integrity.

Weldability

Welding 304 vs 304L shows a clear advantage for 304L. Its low carbon minimizes intergranular corrosion, reducing the risk of weld decay. 304 may require careful control or post-weld annealing to prevent sensitization.

Formability

Both grades are easily formed into complex shapes. 304 offers higher strength for structural components, while 304L excels in parts that require extensive welding and stress relief.

Machinability

304 is slightly tougher on cutting tools due to higher carbon. 304L cuts easier with less tool wear, making it preferable for high-volume CNC production where consistent surface finish is critical.

Annealing

Annealing restores ductility and reduces residual stress. 304L’s low carbon content allows faster annealing cycles and better stability in welded or heavily worked parts.

304 vs 304L Stainless Steel: Applications

304 vs 304L stainless steel finds use in many industries. This chapter highlights the typical applications of each grade, showing where 304 is preferred for strength and general-purpose parts, and where 304L is chosen for welded assemblies, corrosion resistance, and hygienic or chemical environments.

Application of 304 Stainless Steel

• Kitchen and Household：304 stainless steel is widely used in sinks, splashbacks, and sanitaryware, as well as pots, pans, cutlery, flatware, appliances, and electrical enclosures. It also serves in food and beverage processing, equipment for breweries, dairies, and wineries, and tanks, tubing, and storage containers.
• Architectural and Construction：This grade is applied in architectural paneling, trim, and molding, structural elements for buildings, and decorative water and fire features.
• Industrial and Manufacturing：304 stainless steel is used for fasteners like screws, nuts, and bolts, springs, heat exchangers, and woven or welded screens for water filtration.
• Automotive and Aerospace：It is used in automotive and aerospace structural components, including exhaust manifolds and trim.
• Chemical and Medical：304 is employed in chemical containers, laboratory and pharmaceutical equipment, and surgical instruments.

Application of 304L Stainless Steel

• Chemical, Petrochemical, and Pharmaceutical Industries：304L stainless steel is ideal for storage tanks, reactors, pressure vessels, heat exchangers, welded piping systems, and processing, storage, and transport equipment.
• Food and Beverage Industry：It is widely used in brewing, milk processing, and wine-making equipment, as well as sinks, troughs, backsplashes, and kitchen benches. Its hygienic properties make it suitable for food-grade applications.
• Construction and Architecture：304L is used for architectural paneling, building facades, handrails, and decorative trim, combining aesthetic appeal with durability.
• Marine and Industrial Applications：It performs well in corrosive marine environments, and is used for nuts, bolts, and screws, as well as filtration screens for mining, quarrying, and water treatment.
• Other Applications：304L is used in the textile and paper industries for processing equipment, in automotive and aerospace for structural components, and for wire products like mesh, springs, and fasteners

304 vs 304L Stainless Steel: Price

304 vs 304L price difference is generally small, but 304L tends to be slightly higher due to lower carbon content and better weldability. Market fluctuations, supplier, and region also affect pricing. Stainless steel price comparison often shows 304 as more cost-effective for general applications, while 304L is chosen when long-term corrosion resistance and welded assemblies are critical.Understanding stainless steel price comparison helps engineers balance material cost and performance for CNC-machined parts.

The following table lists approximate prices of 304 and 304L stainless steel in different regions, all in USD per kilogram for easy comparison. The table data is updated as of November 2025. Due to market fluctuations, 304 vs 304L price difference may vary. Contact VMT to get the latest quote.

Region	304 Stainless Steel (USD/kg)	304L Stainless Steel (USD/kg)
China	1.70 – 2.20	1.80 – 2.30
Europe	2.10 – 2.80	2.20 – 2.90
USA	2.30 – 3.50	2.40 – 3.60
India / South Asia	1.90 – 2.40	2.00 – 2.50

When Should You Choose 304 Stainless Steel?

• General Corrosion Resistance: 304 stainless steel is highly resistant to a wide range of environments, making it suitable for most indoor and many outdoor applications.
• Ease of Fabrication: It is very ductile and easily formed, welded, and fabricated, making it cost-effective for parts that require significant bending or shaping.
• Architectural and Decorative Uses: 304 is excellent for paneling, trim, and decorative elements where high-quality finish and durability are needed.
• Cost-Sensitive Projects: When the environment does not require the superior corrosion resistance of 316 stainless steel, 304 offers a strong balance of performance and value.

When Should You Choose 304L Stainless Steel?

• Welding applications:The “L” in 304L signifies a low carbon content (0.03% maximum), which is crucial for welded parts. Welding can cause chromium carbide to precipitate, making the metal susceptible to corrosion around the weld. The low carbon in 304L minimizes this effect.
• Corrosion resistance: It offers enhanced corrosion resistance in the “as-welded” condition, making it a preferred choice for applications in corrosive environments like chemical processing and marine settings.
• Heavy-gauge parts: For components that are thick and require welding, 304L is often the best choice because it avoids the need for post-weld heat treatment (annealing) to restore corrosion resistance. This can save time and reduce costs.
• Cost-effectiveness: While similar to 304, the “L” grade can be more cost-effective for welded applications by eliminating the extra step of annealing.

VMT Case: Select Between 304 and 304L Stainless Steel

A German chemical equipment manufacturer approached VMT to produce a welded processing tank for their pharmaceutical division. They initially considered 304 stainless steel due to its strength and lower cost. However, the tank required multiple welded joints and would handle corrosive chemicals, raising concerns about intergranular corrosion and long-term reliability.

VMT engineers recommended 304L stainless steel for its low carbon content and superior corrosion resistance after welding. Using our advanced CNC machining capabilities, we optimized cutting parameters, applied intermediate annealing where needed, and ensured key procedures met CPK ≥1.68. Our 4- and 5-axis centers and surface treatment experts delivered parts with atomic clock-level precision and iPhone-level surface finish.

The finished tank met all specifications and passed strict pharmaceutical industry inspections in Germany. The customer praised the durability, corrosion resistance, and precision of the tank, as well as VMT’s ability to deliver high-quality, welded stainless steel components on schedule. If you want to achieve the same high standards in your CNC-machined components, contact VMT to get professional guidance and the latest stainless steel solutions.

Conclusion

Choosing between 304 and 304L stainless steel depends on the specific requirements of your project, including welding, corrosion exposure, and mechanical performance. 304 offers strength and versatility for general applications, while 304L provides enhanced corrosion resistance for welded structures and harsh environments.