SS304 vs. 304LN Stainless Steel: What’s the Difference?

SS304 vs 304LN Stainless Steel: A Practical Procurement Guide

In the world of industrial procurement, selecting the right grade of stainless steel is critical for ensuring project reliability, cost efficiency, and compliance with technical standards.
Among the popular austenitic stainless steels, SS304 and 304LN often appear side by side in material lists.
While they share many similarities, understanding their subtle differences is key to making an informed purchasing decision.

This guide provides a clear comparison between SS304 and 304LN, focusing on composition, performance, applicable standards, and typical applications.

1. Overview: SS304 and 304LN Stainless Steel

Item	SS304	304LN
Standard References	ASTM A240, ASTM A276, EN 1.4301	ASTM A240, ASTM A276, EN 1.4311
Chemical Composition	18–20% Cr, 8–10.5% Ni, low C (≤0.08%)	17.5–20% Cr, 8–11% Ni, extra-low C (≤0.030%) + N (0.10–0.16%)
Carbon Content	≤0.08%	≤0.030%
Nitrogen Content	Not specified (residual level)	Deliberately added to enhance strength
Corrosion Resistance	Excellent in general environments	Comparable to SS304; slightly better in certain pitting conditions
Strength	Standard strength	Higher yield strength (due to nitrogen addition)
Weldability	Excellent	Excellent, with reduced risk of intergranular corrosion
Price	Lower	10%–20% higher depending on supplier and batch

 

2.What is the difference between 304 and 304N?

2.1. Chemical Composition

SS304 is the industry standard for general-purpose stainless steel, characterized by its balance of corrosion resistance, formability, and cost-effectiveness.

304LN is a low-carbon version of 304, enhanced with nitrogen.

The low carbon content improves resistance to intergranular corrosion after welding.

The added nitrogen increases mechanical strength, especially yield strength, without compromising ductility.

2.2. Mechanical Properties

Because of the nitrogen addition, 304LN offers about 15%–20% higher yield strength compared to SS304.
This advantage makes 304LN particularly suitable for weight-sensitive designs where thinner sections must still meet structural requirements.

Property	SS304 Typical Value	304LN Typical Value
Yield Strength (0.2% offset)	~215 MPa	~300 MPa
Tensile Strength	~505 MPa	~590 MPa

2.3. Welding Performance

SS304 is already well-known for its excellent weldability.

304LN further improves weldability by virtually eliminating the risk of carbide precipitation, thanks to its ultra-low carbon content.
This makes it a better choice for thick-walled structures or high-precision welded assemblies.

 

3. When to Choose SS304 or 304LN?

Application Scenario	Recommended Material	Reason
General-purpose structural components	SS304	Sufficient corrosion resistance, cost-effective
Pressure vessels, piping systems	304LN	Higher strength allows thinner walls, better weld integrity
Cryogenic applications (low temperatures)	304LN	Superior toughness at very low temperatures
Welded heavy-section structures	304LN	Reduced risk of intergranular corrosion after welding
Budget-sensitive projects	SS304	Lower material cost

 

4. What is the equivalent of stainless steel 304L?

When procuring, ensure materials meet applicable standards:

SS304: ASTM A240 / A276, EN 1.4301, JIS SUS304

304LN: ASTM A240 / A276 (Grade 304LN), EN 1.4311, JIS SUS304LN

Certification documents such as Mill Test Certificates (MTC) should clearly indicate chemical composition, mechanical properties, and heat treatment conditions.

 

5. Conclusion: Procurement Decision Tips

For general fabrication and non-critical environments, SS304 offers the best cost-performance balance.

For high-performance structures requiring enhanced strength, better weldability, or operation at cryogenic temperatures, 304LN is the superior choice.

Always verify the application's technical requirements before finalizing the material selection - choosing the right grade can reduce maintenance costs, improve safety margins, and extend service life.