What is the difference between AISI 304 and AISI 304L?

What is 304 stainless steel?
304 stainless steel, also known as A2 or 18/8 stainless steel, contains 18% chromium and 8% nickel, offering good corrosion resistance, formability, and durability. It cannot be hardened by heat treatment and is typically used in the annealed condition. It is weldable and machinable and is commonly used in sinks, food storage tanks, surgical instruments, and exhaust systems.

 

What is 304L stainless steel?
304L stainless steel is a strong, silver-gray alloy composed of 70% iron, 18% chromium, and 8% nickel. The "L" stands for "low carbon," with a carbon content of 0.03%, lower than 304 stainless steel. This prevents carbide precipitation during welding and improves corrosion resistance. It performs well in corrosive environments without requiring annealing. This material is primarily used in industries such as chemical processing, food and beverage manufacturing, and construction.

 

The difference in chemical composition between AISI 304 and AISI 304L

Element	AISI 304	AISI 304L
Carbon (C)	≤0.08%	≤0.03% (Low carbon)
Chromium (Cr)	18–20%	18–20%
Nickel (Ni)	8–10.5%	8–12%
Manganese (Mn)	≤2.0%	≤2.0%

 

Differences in Mechanical Properties between AISI 304 and AISI 304L

Property	AISI 304	AISI 304L
Tensile Strength	515–720 MPa	485–680 MPa
Yield Strength	205 MPa (min)	170 MPa (min)
Elongation	40–50%	40–50%
Hardness (Brinell)	201 HB	201 HB

 

Corrosion Resistance
AISI 304:
Excellent overall corrosion resistance in mild environments (e.g., fresh water, atmospheric exposure).
Disadvantage: Susceptible to intergranular corrosion (sensitization) in the welded area at temperatures between 425–815°C.
AISI 304L:
Excellent resistance to sensitization due to its low carbon content.
Ideal for welded components in corrosive environments (e.g., chemical processing, marine applications).

 

Applications of 304 and 304L stainless steel in various industries

Industry	AISI 304 Applications	AISI 304L Applications
Food & Beverage	Countertops, storage tanks	Welded piping, fermentation vessels
Architecture	Decorative trim, handrails	Structural welded frameworks
Chemical	Non-welded containers	Heat exchangers, reactors
Pharmaceutical	Equipment surfaces	Sterilizable welded systems

 

Equivalent Grades of 304 and 304L

Country/Standard	Specification	Grade (304)	Grade (304L)
United States	ASTM A240, ASTM A312	304	304L
China	GB/T 1220, GB/T 14975	0Cr18Ni9	00Cr19Ni10
Japan	JIS G4304, JIS G4305	SUS304	SUS304L
International	ISO 15510	X5CrNi18-10	X2CrNi19-11
Europe	EN 10088-2	1.4301	1.4307

 

Applications of 304 and 304L Stainless Steel
Although 304 and 304L stainless steels have similar chemical and physical properties, their differing carbon content leads to differences in their application areas. These differences determine the most suitable applications for each grade.

 

Applications of 304 Stainless Steel
Structural components: Used in building frames, bridges, and load-bearing structures.
Automotive parts: Commonly used in exhaust systems, engine components, and decorative trim.
Industrial equipment: Suitable for tanks, pipes, and machinery exposed to various chemicals.
Consumer goods: Used in kitchen sinks, cookware, and household appliances.
Medical devices: Used 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 for welded pipes, tanks, and heat exchangers.
Chemical processing: Used in equipment for handling corrosive chemicals, such as reactors and mixing tanks.
Marine environments: Suitable for shipbuilding, offshore platforms, and underwater pipelines.
Pharmaceutical equipment: Applied in drug manufacturing equipment where high purity is required.
Food processing: Ideal for handling acidic foods and beverages, such as fermentation tanks and food storage units.

 

Why choose Gnee as your stainless steel supplier?

✅ Over 18 years of export experience, with products sold to more than 80 countries

✅ ISO, SGS, and BV certified

✅ Ample global stock of 304, 316, 316L, and 321 alloy pipes, plates, and bars

✅ Customized processing services available, including cutting, polishing, CNC machining, and packaging

✅ Fast delivery in 7-15 days, supported by global logistics partners

📦 Packaging and Shipping

All stainless steel products are packaged as follows:

Wooden pallets or wooden crates

Moisture-proof packaging

Labeled with heat number, standard, and dimensions

Shipped worldwide via sea, air, or express delivery