What is S355M?
S355M is a thermo-mechanically rolled, fine-grain structural steel specified in EN 10025-4.
It combines high yield strength (355 MPa) with excellent toughness, weldability, and formability, making it suitable for bridges, offshore structures, cranes, heavy machinery, and construction projects.
Designation meaning:
S = Structural steel
355 = Minimum yield strength (MPa)
M = Thermo-mechanically rolled
1. Chemical Composition (Typical, %)
| Element | C (max) | Si | Mn | P (max) | S (max) | Nb | V | Ti |
|---|---|---|---|---|---|---|---|---|
| S355M | 0.22 | ≤ 0.55 | 1.00–1.60 | 0.025 | 0.020 | ≤ 0.06 | ≤ 0.12 | ≤ 0.03 |
2. Mechanical Properties
| Property | Value |
|---|---|
| Yield Strength (≤16 mm) | 355 MPa |
| Yield Strength (40–100 mm) | 345–355 MPa |
| Tensile Strength | 470–630 MPa |
| Elongation (A5) | ≥ 22% |
| Charpy Impact | ≥ 27 J at –20°C |
| Density | 7.85 g/cm³ |
What is the minimum yield strength of S355M?
The minimum yield strength of S355M depends on the plate thickness, according to EN 10025-4.
| Plate Thickness | Minimum Yield Strength (MPa) |
|---|---|
| ≤ 16 mm | 355 MPa |
| 16–40 mm | 345 MPa |
| 40–63 mm | 335 MPa |
| 63–100 mm | 325 MPa |
| >100 mm | 315 MPa |
Summary:
S355M provides a minimum yield strength of 355 MPa for thinner plates (≤16 mm), decreasing slightly for thicker plates due to thermo-mechanical rolling constraints.
The "M" grade ensures high toughness, good weldability, and consistent mechanical properties, suitable for bridges, offshore structures, cranes, and cold-climate applications.
Which industries rely most on S355M plates?
S355M plates are widely used in industries requiring high-strength, durable, and tough structural steel. Key sectors include:
Construction & Civil Engineering: Bridges, building frameworks, and structural supports.
Offshore & Marine: Platforms, shipbuilding, and cold-climate structures.
Heavy Machinery & Equipment: Cranes, industrial machinery, and material handling structures.
Energy & Power: Wind towers, transmission towers, and steel frameworks for power plants.
Transportation & Infrastructure: Railway bridges, tunnels, and port structures.
Their combination of high yield strength, weldability, and low-temperature toughness makes S355M ideal for demanding load-bearing applications.
GNEE Steel also supplies a variety of high-strength steel plates, such as A514 Grade F, A572 Grade 50, A588 Grade A, S355JR, S690Q, SS400, S690QL, Q345B, Q345E, etc. If you want to know more about other types of steel plates, you can call the consultation hotline at +8615824687445 or send an email to info@gneesteels.com. You are welcome to consult us, and we are very willing to answer your questions.
