The Differences Between 304, 304L, and 304H

What is 304 Stainless Steel?

304 stainless steel is the most widely used and common type of austenitic stainless steel; its composition contains 18% to 20% chromium and 8% to 10.5% nickel. Possessing excellent corrosion resistance, high durability, and good formability, it is an ideal material choice for kitchenware, food processing equipment, and architectural applications. Furthermore, it is non-magnetic, exhibits good heat resistance, and is easy to process.

 

What is type 304L stainless steel?

304L stainless steel is a low-carbon (< 0.03%) austenitic 18/8 chromium-nickel alloy, widely utilized for its exceptional corrosion resistance and excellent weldability. As a variant of Type 304 stainless steel, it prevents carbon precipitation during welding, thereby eliminating the need for post-weld annealing. Its common applications include equipment for the chemical, pharmaceutical, and food processing industries, as well as architectural panels and thick-section components.

 

What material is 304H?

304H is a high-carbon, austenitic stainless steel (UNS S30409) designed for elevated temperature applications. As a high-carbon variant of 304/304L, it provides increased strength and superior creep resistance at temperatures up to 870°C, making it ideal for pressure vessels, boilers, and heat exchangers.

 

304 vs. 304L vs. 304H: Chemical Composition (%)

Grade	C (Carbon)	Mn (Manganese)	Si (Silicon)	Cr (Chromium)	Ni (Nickel)	P (Phosphorus)	S (Sulfur)
304	≤ 0.08	≤ 2.00	≤ 0.75	18.0 – 20.0	8.0 – 10.5	≤ 0.045	≤ 0.030
304L	≤ 0.03	≤ 2.00	≤ 0.75	18.0 – 20.0	8.0 – 12.0	≤ 0.045	≤ 0.030
304H	0.04 – 0.10	≤ 2.00	≤ 0.75	18.0 – 20.0	8.0 – 10.5	≤ 0.045	≤ 0.030

 

304 vs. 304L vs. 304H: Mechanical Properties (Typical at Room Temperature)

Grade	Tensile Strength (MPa)	Yield Strength (MPa)	Elongation (%)	Hardness (HB)
304	≥ 515	≥ 205	≥ 40	≤ 201
304L	≥ 485	≥ 170	≥ 40	≤ 201
304H	≥ 515	≥ 205	≥ 40	≤ 201

 

304 vs. 304L vs. 304H: Physical Properties

Property	304	304L	304H
Density (g/cm³)	8.0	8.0	8.0
Melting Range (°C)	1400 – 1450	1400 – 1450	1400 – 1450
Thermal Conductivity (W/m·K, at 100°C)	16.2	16.2	16.2
Electrical Resistivity (µΩ·m)	0.72	0.72	0.72
Specific Heat (J/kg·K)	500	500	500

 

304 vs. 304L vs. 304H:Corrosion Resistance

In terms of corrosion resistance, 304L stainless steel demonstrates superior performance in welded structures, primarily due to its extremely low carbon content (≤0.03%); this characteristic effectively mitigates the risks of carbide precipitation and intergranular corrosion. Standard 304 stainless steel (≤0.08% C) provides reliable corrosion resistance in most conventional environments; however, if not subjected to appropriate post-weld heat treatment, it may become susceptible to intergranular corrosion.
In contrast, 304H stainless steel (0.04–0.10% C) is specifically engineered for high-temperature applications, where its higher carbon content effectively enhances the material's oxidation resistance and creep strength; nevertheless, this also renders it more prone to sensitization in specific corrosive environments.

304 vs. 304L vs. 304H:Weldability

Thanks to its extremely low carbon content (≤0.03%), 304L exhibits exceptional weldability; it effectively prevents intergranular corrosion (sensitization) in the weld zone and requires no post-weld annealing treatment. As the standard grade, 304 offers good weldability; however, when welding thick-section materials, there remains a risk of sensitization. In contrast, 304H possesses superior high-temperature strength due to its higher carbon content (0.04%–0.10%), yet it demands extra caution during welding to effectively mitigate the risk of sensitization.

304 vs. 304L vs. 304H:Applications

Industry / Scenario	Recommended Grade	Typical Use Cases
Food & Beverage	304 / 304L	Milk tanks, brewery piping, kitchen equipment.
Heavy Weldments	304L	Chemical storage tanks, pressure vessels, large-scale piping.
High-Temp Energy	304H	Boiler tubes, steam headers, heat exchangers (above 500°C).
Architecture	304	Railings, elevator interiors, facade cladding.
Chemical Plants	304L	Acid transport lines, fertilizer production equipment.
Oil & Gas (Refining)	304H	Catalytic cracking units, flare stacks, high-temp piping.
Medical / Pharma	304L	Surgical instruments, vaccine storage, laboratory benches.

 

 Can 304, 304L, and 304H pipes be used interchangeably?

Although 304, 304L, and 304H pipes share similar fundamental characteristics, they are not entirely interchangeable due to differences in carbon content, which subsequently affect their high-temperature strength and weldability. Specifically, 304L (low carbon) is best suited for welding applications; 304H (high carbon) is designed for high-temperature environments; while standard 304 is suitable for general-purpose use-though in practice, dual-certified products are also quite common.

 

 

At GNEE, we fully understand that a procurement manager's greatest concern is material failure. To address this, we tackle the various challenges associated with the 304 series materials through the following measures:

Click to Get 304, 304L, and 304H Inventory List

 

Dual Certification Assurance: We primarily stock 304/304L materials that hold "Dual Certification" status.
PMI Verification: Before any batch of material leaves our facility, it undergoes rigorous Positive Material Identification (PMI) testing.

Technical Feasibility Assessment: Are you unsure whether 304L material is strictly necessary for your thin-wall tubing applications? Our metallurgical engineers are available to provide expert technical feasibility assessments to assist you in making informed decisions.
Global Logistics Services: Whether you require 304L plates for a tank storage project in Europe or 304H tubing for a refinery in the Middle East, our dedicated logistics team ensures that your materials are properly packaged and accompanied by all necessary documentation, guaranteeing smooth customs clearance and a delay-free delivery process.