Stainless Steel SS304: A chromium-nickel austenitic stainless steel with up to 0.08% carbon, offering higher strength for structural applications like pressure vessels and architectural panels.
Stainless Steel 304L: A low-carbon variant of 304 with ≤0.03% carbon, designed for superior weldability by reducing the risk of sensitization (chromium carbide precipitation), ideal for welded applications like chemical tanks and food processing equipment.
Chemical Composition Comparison
|
Element |
SS304 (%) |
304L (%) |
|---|---|---|
|
Carbon (C) |
0.00 - 0.08 |
0.00 - 0.03 |
|
Manganese (Mn) |
0.00 - 2.00 |
0.00 - 2.00 |
|
Silicon (Si) |
0.00 - 0.75 |
0.00 - 0.75 |
|
Phosphorus (P) |
0.00 - 0.045 |
0.00 - 0.045 |
|
Sulfur (S) |
0.00 - 0.030 |
0.00 - 0.030 |
|
Chromium (Cr) |
18.00 - 20.00 |
18.00 - 20.00 |
|
Nickel (Ni) |
8.00 - 10.50 |
8.00 - 12.00 |
|
Nitrogen (N) |
0.00 - 0.10 |
0.00 - 0.10 |
|
Iron (Fe) |
Balance |
Balance |
Mechanical Properties Comparison
|
Property |
SS304 (Min) |
304L (Min) |
Notes |
|---|---|---|---|
|
Tensile Strength (MPa) |
515 |
485 |
304 is stronger due to higher carbon |
|
Yield Strength (0.2% Offset, MPa) |
205 |
170 |
304L sacrifices strength for weldability |
|
Elongation (A5, 50 mm) |
40% |
40% |
Both highly formable |
|
Hardness (Brinell) |
≤ 201 HB |
≤ 201 HB |
Similar machinability |
|
Hardness (Rockwell B) |
≤ 92 HRB |
≤ 92 HRB |
Similar machinability |
Corrosion Resistance Comparison
Both stainless steel SS304 and 304L offer excellent corrosion resistance in:
Atmospheric conditions, freshwater, and mild acids (food-grade applications).
General environments, outperforming SS204 vs SS 304 due to higher nickel content.
Key differences:
304L: Superior in welded applications, as its low carbon content prevents sensitization, maintaining corrosion resistance in weld zones, especially in corrosive environments like chemical processing.
SS304: Slightly more prone to sensitization during welding, requiring controlled heat input or post-weld annealing to maintain corrosion resistance.
Both are less resistant to chloride-induced pitting compared to 316L, which contains molybdenum. For chloride-heavy environments, explore 316L.
Weldability Comparison
SS304: Good weldability with ER308 or ER308L fillers, but higher carbon (≤0.08%) increases the risk of sensitization (chromium carbide precipitation) in welded zones, potentially reducing corrosion resistance unless annealed.
304L: Excellent weldability due to low carbon (≤0.03%), minimizing sensitization and often eliminating the need for post-weld annealing. Preferred for welded applications like SA 240 GR 304 pipe or chemical tanks.
Applications
Stainless Steel SS304: Preferred for non-welded structural applications (e.g., plat SS 304 3mm, architectural panels, pressure vessels) where higher strength is needed. Competitive SS 304 plate price for general uses.
Stainless Steel 304L: Ideal for welded applications (e.g., food processing tanks, 304L pipe, chemical equipment) due to superior weldability and corrosion resistance post-welding.
