S235 / S275 / S355 Structural Steel Comparison and Properties

Introduction

When purchasing structural steel for construction or industrial projects, understanding the differences between S235, S275, and S355 grades is essential. 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.

S235 vs S275 vs S355 – 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 and Tensile Strength of S235, S275 and S355 Steel

The key difference among these grades lies in their strength.

Property	S235	S275	S355
Yield Strength (MPa)	235	275	355
Tensile Strength (MPa)	360–510	370–530	470–630
Elongation (%)	≥26	≥23	≥22
Impact Resistance	Basic	Improved	Excellent, suitable for low temperatures
Weldability	Excellent	Excellent	Good
Formability	High	Moderate	Lower

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.

In practice, the difference between S235 and S275 is small for general use, but S355 vs S275 represents a significant jump in load capacity and resilience, especially under dynamic or cold conditions.

Chemical Composition of S235, S275 and S355 (C & Mn Comparison)

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

Grade	Carbon (C %)	Manganese (Mn %)	Explanation
S235	≤0.17	≤1.40	Low carbon, excellent weldability, lower strength
S275	≤0.21	≤1.50	Slightly higher carbon & manganese, balanced properties
S355	≤0.24	≤1.60	Higher C & Mn levels, resulting in higher yield strength

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

Cost & Availability Comparison

Grade	Relative Cost	Typical Availability	Notes
S235	100% (baseline)	Common stock	Widely available in all thicknesses
S275	+10–15%	Common stock	Standard for general construction
S355	+25–30%	Some sizes need rolling	Higher strength, less stock flexibility

For most export orders or construction projects, S235 and S275 are generally available from warehouse stock, while S355 may require custom rolling for thicker plates or uncommon dimensions.

Applications of S235 / S275 / S355 Structural Steel

Choosing between S235, S275, and S355 depends on both structural requirements and project environment.

S235 – For Light Structures and General Fabrication

• Ideal for frames, fences, containers, and small workshops.
• High weldability and formability make it easy for fabrication and assembly.
• Best choice for low-load, cost-sensitive projects.

👉 Related product:

• A36/Q235/S235JR Carbon Steel Coil
• A36/Q235/S235JR Carbon Steel Plate
• EN 10219/S235 Welded Steel Pipe

S275 – For Medium-Strength Structures

• Common in commercial buildings, bridges, and heavy machinery bases.
• Offers a good balance between strength, ductility, and price.
• Often used when S235 is too soft but S355 is unnecessary.

S355 – For Heavy-Duty or Dynamic Loads

• Used in bridges, offshore platforms, wind towers, and high-rise structures.
• Superior yield strength and impact toughness, especially in low temperatures.
• Though costlier, its long-term durability and load efficiency justify the investment.

👉 Related product:

• S355JR Carbon Steel Plate
• S355J2 / S355JR Wind Tower Steel Plate

S235, S275 and S355 Material Equivalents

In global procurement, buyers often care about S235 steel equivalent, S275 material equivalent, or S355 steel equivalent to ensure compatibility with regional standards such as ASTM, JIS, or GB.
Below is a simplified equivalence chart:

EN Standard	ASTM Equivalent	JIS Equivalent	GB Equivalent
S235JR	ASTM A36	SS400	Q235B
S275JR	ASTM A36 / ASTM A529	SM400A / B	Q275
S355JR	ASTM A572	SM490A / B	Q345B

How to Choose Between S235, S275, and S355 Steel Grades

Project Type	Recommended Grade	Reason
Light framing, warehouse structure	S235	Easy fabrication, lowest cost
Commercial or bridge structure	S275	Higher load capacity, moderate cost
Offshore or high-rise building	S355	High strength, excellent toughness

If you are comparing S275 vs S355, consider not only the static load but also the environmental factors — such as wind, vibration, and temperature. For example, S355 performs significantly better in offshore or cold regions due to its higher impact resistance.

Frequently Asked Questions

• Q: What is the main difference between S235, S275, and S355 steel?
  A: The main difference lies in yield strength — 235, 275, and 355 MPa respectively — and their corresponding applications. S355 offers the best performance for high-load or harsh environments.
• Q: Which grade is best for construction projects?
  A: For general building structures, S275 is the most widely used. For bridges or wind towers, S355 is preferred due to better toughness and fatigue resistance.
• Q: Can I use S235 instead of S275?
  A: Yes, for light structures or fabrication projects where load demands are low. But for safety-critical parts, S275 or S355 is more reliable.

Conclusion

When choosing between S235 vs S275 vs S355, the best grade depends on your project’s strength requirement, budget, and delivery schedule.

• S235 – Economical, easy to fabricate.
• S275 – Balanced performance and cost.
• S355 – Premium grade for demanding structures.

For most construction exporters and distributors, a combination of S235 and S275 ensures quick delivery, while S355 is reserved for projects where safety and durability are paramount.

👉 Looking for reliable supply? Contact our team for details.