S235 / S275 / S355 Structural Steel Comparison and Properties

Introduction

When purchasing structural steel for construction or industrial projects, buyers often encounter European grades S235 steel, S275 steel, and S355 steel. These grades are defined under the EN 10025 standard and represent the most widely used materials in buildings, bridges, offshore structures, and heavy machinery.

This page provides a comparison of S235 yield strength, S275 yield strength, and S355 yield strength, along with their chemical composition, mechanical properties, and equivalent standards in ASTM, JIS, and other specifications.

Grade Overview

The designation system in EN 10025 is straightforward:

• The letter “S” stands for structural steel.
• The number represents the minimum yield strength in N/mm².

Therefore:

• S235 → minimum yield strength 235 MPa.
• S275 → minimum yield strength 275 MPa.
• S355 → minimum yield strength 355 MPa.

These grades also have suffixes like S235JR, S275JR, and S355JR, which indicate impact toughness requirements. For example, “JR” means the steel has been tested for impact at room temperature.

👉 For more details on suffixes like JR, J2, and NL, see our guide: S355JR / S355J2 / S355NL – What’s the Difference?

Mechanical Properties of S235, S275, and S355

The key difference among these grades lies in their strength.

From this comparison, it is clear that S355 yield strength offers a significant increase over S235 yield strength and S275 yield strength, making it the preferred choice for heavy load-bearing applications.

Chemical Composition Comparison (C & Mn)

The difference in yield strength comes primarily from the carbon and manganese content.

Engineers should note that while increasing C and Mn enhances strength, it can slightly reduce weldability.

Applications of S235 / S275 / S355 Structural Steel

Each grade has typical applications depending on strength requirements:

• S235 steel – residential buildings, light structural work, low-load bearing parts.
• S275 steel – medium-sized structures such as warehouses, transmission towers, and pipelines.
• S355 steel – bridges, offshore wind towers, heavy equipment, and structural frames.

👉 For deeper insights, refer to our blog: S235 vs S355 Steel in Construction: Choosing the Right Grade

Equivalent Standards (ASTM, JIS, GB)

S235, S275, and S355 equivalents are frequently requested by global buyers. Below is a simplified equivalence chart:

Buyer Considerations

When choosing between S235, S275, and S355, buyers should consider:

1. Strength requirements – higher grades support heavier loads.
2. Weldability – lower grades like S235 weld more easily.
3. Cost vs performance – S355 steel is more expensive but provides longer service life.
4. Standards compliance – confirm EN 10025 certificates and equivalents for international projects.

Conclusion

The S235 / S275 / S355 family of EN 10025 structural steels covers a wide range of applications, from simple construction to demanding offshore engineering. By understanding their differences in strength, weldability, and equivalents, buyers can make informed procurement decisions.

👉 Looking for reliable supply? Check our stock:

• A36/Q235/S235JR Carbon Steel Coil
• A36/Q235/S235JR Carbon Steel Plate
• A572/S355JR Carbon Steel Coil
• A572/S355JR Carbon Steel Plate
• EN 10219/S235 Welded Steel Pipe
• A572/S355JR Round Steel Bar