Type 304 and 304L Stainless Steel
Dec 23, 2025
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304 vs. 304L Stainless Steel: A Comprehensive Comparison and Selection Guide
As the most common members of the 300 series austenitic stainless steels, Type 304 and its low-carbon version, Type 304L, are used extensively across industries ranging from food processing to heavy chemical engineering. While they share many similarities, understanding the subtle differences between these two grades is essential for ensuring long-term structural integrity, especially in welded applications.
What are the advantages of 304 stainless steel?
304 stainless steel offers high corrosion resistance, great durability, and ease of cleaning because of its 18% chromium and 8% nickel composition. It is cost-effective, simple to weld and shape, and safe for food handling, making it the most popular alloy for industrial and household uses.
What does the L mean in 304L stainless steel?
The "L" in 304L stainless steel stands for low carbon. It has a maximum carbon limit of 0.03%, compared to standard grade 304 which allows up to 0.08%. This lower carbon amount stops harmful carbide deposits from forming during welding.
What is the difference between stainless steel 304 and 304L?
The primary difference between 304 and 304L stainless steel is carbon content. Grade 304 has a maximum carbon limit of 0.08%, while 304L (the "L" stands for low carbon) limits carbon to a maximum of 0.03%. This lower carbon level prevents harmful carbide precipitation during heavy welding.
304 and 304L Stainless Steel Composition:
| Element (%) | Type 304 (UNS S30400) | Type 304L (UNS S30403) |
|---|---|---|
| Carbon (C) | 0.08 max | 0.03 max |
| Chromium (Cr) | 18.0 - 20.0 | 18.0 - 20.0 |
| Nickel (Ni) | 8.0 - 10.5 | 8.0 - 12.0 |
| Manganese (Mn) | 2.00 max | 2.00 max |
| Nitrogen (N) | 0.10 max | 0.10 max |
| Iron (Fe) | Balance | Balance |
Physical Properties Comparison: 304 vs 304L Stainless Steel
| Property | 304 Stainless Steel | 304L Stainless Steel | Notes / Common Value |
|---|---|---|---|
| Density | 8.0 g/cm³ | 8.0 g/cm³ | Identical |
| Melting Point | ~1400-1450°C | ~1400-1450°C | Identical |
| Specific Heat Capacity | ~500 J/kg·K | ~500 J/kg·K | Identical |
| Thermal Conductivity | ~16.2 W/m·K | ~16.2 W/m·K | At 100°C |
| Thermal Expansion | ~17.2 μm/m·°C | ~17.2 μm/m·°C | 20-100°C range |
| Electrical Resistivity | ~0.72 μΩ·m | ~0.72 μΩ·m | At 20°C |
| Modulus of Elasticity | ~193 GPa | ~193 GPa | Identical |
304 vs. 304L Stainless Steel: Corrosion Resistance
Grade 304 and 304L stainless steel offer virtually identical general corrosion resistance in un-welded, everyday environments. The primary difference is carbon content-304 has a maximum of 0.08%, while 304L ("Low Carbon") has a maximum of 0.03%. This lower carbon level prevents harmful carbide precipitation during welding, giving 304L superior resistance to intergranular corrosion near weld joints.
304 vs. 304L Stainless Steel: Weldability
The core difference in weldability between 304 and 304L stainless steel is carbon content. Type 304 allows up to 0.08% carbon, while 304L restricts it to a maximum of 0.03%. This lower carbon level in 304L prevents harmful chromium carbide precipitation during welding, eliminating intergranular corrosion and the need for post-weld annealing.
Common applications:
The choice of specific grade depends largely on manufacturing requirements:
304: General-purpose products, kitchen sinks, decorative trim, and light-duty components requiring minimal welding. 304L: Heavy-walled components, chemical storage tanks, pressure vessels, and large-scale industrial piping systems.
If you are planning a project, tell me:
Are you welding the material?
What is the thickness of the metal?
What kind of environment will it face?
We provide a comprehensive range of stainless steel grades, including the widely used 304 and 316 series, as well as specialized grades such as 430, 201, duplex, and super austenitic steels, tailored to meet diverse industrial and environmental requirements. Whether you need corrosion-resistant solutions for marine applications, food-grade compliance, high-temperature durability, or custom specifications, our expert team is ready to assist.
304/304L Stainless Steel Specifications
| Category | Product Form | Typical Size Range | Standard (ASTM/ASME) | Common Finish/Condition |
| Flat Products | Cold Rolled Sheet | 0.3mm – 6.0mm (T) | ASTM A240 | 2B, BA, No.4 (Brushed), Mirror |
| Hot Rolled Plate | 3.0mm – 100mm+ (T) | ASTM A240 | No.1 (Pickled), Sandblasted | |
| Coil / Strip | Width: 5mm – 1500mm | ASTM A240 | 2B, BA, No.4, Polished | |
| Long Products | Round Bar | Φ 2mm – 500mm | ASTM A276 / A479 | Bright, Peeled, Polished, Black |
| Hexagonal Bar | S 5mm – 100mm | ASTM A276 | Cold Drawn, Bright | |
| Square Bar | 5x5mm – 150x150mm | ASTM A276 | Cold Drawn, Polished, Pickled | |
| Flat Bar | 2x20mm – 20x150mm | ASTM A276 | HRAP (Hot Rolled Annealed Pickled) | |
| Angle Bar | 20x20mm – 100x100mm | ASTM A276 | Pickled, Sandblasted | |
| Channel / Beam | Various structural sizes | ASTM A276 | Hot Rolled, Pickled | |
| Tubular Products | Industrial Pipe | 1/8" – 48" (NPS) | ASTM A312 | SMLS/Welded, Pickled, Polished |
| Sanitary Tube | OD 12.7mm – 203.2mm | ASTM A270 | Mirror Polished (Internal/External) | |
| Structural Tube | Square & Rectangular | ASTM A554 | Brushed (Hairline), No.4 | |
| Heat Exchanger Tube | OD 6mm – 114.3mm | ASTM A213 / A269 | Bright Annealed (BA), Pickled | |
| Fittings / Flanges | Buttweld Fittings | Elbow, Tee, Reducer | ASTM A403 | Shot Blasted, Pickled |
| Forged Fittings | Union, Coupling, Plug | ASTM A182 | Threaded (NPT/BSP), Socket Weld | |
| Flanges | WN, SO, Blind, Plate | ASTM A182 | Machined, RF (Raised Face) | |
| Wire Products | Spring/Heading Wire | Φ 0.1mm – 20mm | ASTM A313 / A493 | Bright, Soap Coated, Matte |
FAQ
1. Is 304L more expensive than 304?
Historically, 304L commanded a slight premium, but due to modern production efficiencies, the price difference is now negligible for most standard products like sheets and plates.
2. Can I use 304L in place of 304?
Yes, in most cases 304L can replace 304, provided that the slightly lower yield strength is accounted for in the structural design. However, dual-certified material is the ideal solution to avoid strength trade-offs.
3. How does 304L compare to 316L?
While both are low-carbon grades, 316L contains molybdenum (2-3%), which provides superior resistance to chlorides and pitting compared to 304L. For marine or highly saline environments, 316L is generally preferred.
4. Is 304L magnetic?
Like all 300 series austenitic steels, 304L is non-magnetic in the annealed condition. However, it may become slightly magnetic after cold working or welding.
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