Overview of S275 Carbon Steel
S275 is a non-alloy, low carbon structural steel defined by the European standard EN 10025-2. The "S" stands for "Structural Steel," and the "275" indicates the minimum yield strength of 275 MPa (Megapascals) for thicker material sections (≤ 16mm).
When supplied as a pipe or tube, it is typically governed by a different set of standards, which will be covered below.
Key Characteristics and Properties
Good Strength and Ductility: With a yield strength ranging from 275 MPa to 235 MPa (depending on thickness) and a tensile strength of 410 to 560 MPa, it offers a excellent balance for structural applications. It is easy to form and weld.
Excellent Weldability: Due to its low carbon content, S275 steel can be welded easily using all conventional methods without pre or post-heating (in most cases), making it highly suitable for fabricated structures.
Machinability: It has good machinability in its normalized or hot-rolled condition.
Impact Resistance: It provides adequate impact resistance for most general construction purposes.
Mechanical Properties (EN 10025-2 for flat product reference)
| Material Thickness (t) | Yield Strength (min, MPa) | Tensile Strength (MPa) | Elongation (min, %) |
|---|---|---|---|
| t ≤ 16 mm | 275 MPa | 410 - 560 MPa | 23 |
| 16 mm < t ≤ 40 mm | 265 MPa | 410 - 560 MPa | 23 |
| 40 mm < t ≤ 63 mm | 255 MPa | 410 - 560 MPa | 22 |
| 63 mm < t ≤ 80 mm | 245 MPa | 410 - 560 MPa | 21 |
| 80 mm < t ≤ 100 mm | 235 MPa | 410 - 560 MPa | 21 |
Note: The exact properties of the finished pipe will be specified in the relevant tube/pipe standard.
Relevant Standards for S275 Steel Pipe
S275 material is formed into pipes and tubes under various European standards. The most common ones are:
EN 10210-1 & EN 10210-2: Hot Finished Structural Hollow Sections
This is the most common standard for S275 structural pipes (often called HFS - Hot Finished Seamless or HFW - Hot Finished Welded).
These pipes are used for construction frameworks, support columns, and other load-bearing structures.
The steel grade is typically designated as S275J0H or S275J2H. The "H" indicates that it is suitable for hollow sections. "J0" and "J2" denote different levels of impact toughness (Charpy V-notch) at 0°C and -20°C, respectively.
EN 10219-1 & EN 10219-2: Cold Formed Structural Hollow Sections
These are cold-formed welded pipes. They are generally less expensive than hot-finished but have slightly different mechanical properties due to the manufacturing process.
The grade designations are the same: S275J0H and S275J2H.
EN 10255: Non-Alloy Steel Tubes Suitable for Welding and Threading
This standard covers pipes used for general engineering and pressure purposes. S275 can be supplied under this standard, often for less critical applications.
Common Applications
S275 steel pipes are versatile and used in a wide range of industries:
Construction and Building Frames: As columns, beams, and trusses in commercial and industrial buildings.
Structural Supports: For platforms, walkways, and guard rails.
Mechanical and General Engineering: For machine frames, supports, and structural components where high strength is not the primary requirement.
Infrastructure Projects: In bridges, stadiums, and other large-scale structures.
Pipelines: For transporting water, air, and other non-corrosive fluids at low pressures.
Comparison with Other Common Grades
| Property | S235 | S275 | S355 |
|---|---|---|---|
| Yield Strength (min) | 235 MPa | 275 MPa | 355 MPa |
| Tensile Strength | 360-510 MPa | 410-560 MPa | 470-630 MPa |
| Carbon Content | Lower | Slightly Higher | Higher |
| Strength | Lower | Medium | Higher |
| Cost | Lower | Medium | Higher |
Summary: S275 offers a significant strength increase over S235 without a major cost jump, making it a very popular and cost-effective choice for many structural applications. S355 is stronger but also more expensive.
Equivalent Grades in Other Standards
It's important to know the equivalent materials in different regional standards.
USA (ASTM): A36 is a very close equivalent in terms of mechanical properties and application. ASTM A53 Grade B is also a common pipe equivalent.
China (GB): Q275 is a direct equivalent.
International (ISO): Fe430B (according to ISO 630-2).
Summary
S275 carbon steel pipe is a versatile, economical, and widely available structural steel product. Its excellent weldability, good strength, and formability make it a top choice for a vast array of construction and engineering projects where high strength or corrosion resistance is not a critical requirement. When sourcing, always confirm the specific pipe standard (e.g., EN 10210) and the sub-grade (e.g., S275J2H) to ensure it meets your project's mechanical and toughness requirements.
