S355MLO Properties EN 10025-4 Mechanical Supplier

 

 

S355MLO Properties – EN 10025-4 Mechanical Characteristics

S355MLO is a thermomechanically rolled low-temperature structural steel grade defined in EN 10025-4.
With high yield strength, excellent weldability, and certified impact toughness at –40°C, it is widely used in offshore structures, heavy engineering, oil & gas modules, and cold-climate applications.

Gangsteel supplies S355MLO plates with strict TMCP rolling control, ensuring reliable strength and superior toughness.

Mechanical Properties of S355MLO

S355MLO offers consistent mechanical performance across a wide range of thicknesses.

Mechanical Property	Requirement	Notes
Yield Strength (ReH)	355–420 MPa(depends on thickness)	High strength for structural use
Tensile Strength (Rm)	470–630 MPa	Stable TMCP microstructure
Elongation (A5)	≥ 22%	Excellent ductility and forming ability
Impact Toughness	27 J at –40°C (O grade)	Guaranteed low-temperature performance
Plate Thickness Range	6–150 mm	Available from Gangsteel

These mechanical properties make S355MLO suitable for both static and dynamic loading structures.

Low-Temperature Toughness (O Grade)

The suffix “O” in S355MLO means the steel is tested at:

• –40°C Charpy V-notch impact energy ≥ 27 Joules

S355MLO maintains stable toughness even in extremely cold conditions, making it ideal for:

• Arctic environment steel
• Offshore wind towers
• LNG & cold-storage infrastructure
• Marine structures
• Dynamic loading frameworks

TMCP rolling ensures finer grain structure, which greatly improves brittle-fracture resistance at low temperatures.

Yield Strength Behavior by Thickness

As with other structural steels, yield strength reduces slightly as thickness increases due to metallurgical constraints.

Typical values:

• t ≤ 16 mm → 420 MPa
• 16 mm < t ≤ 40 mm → 400 MPa
• 40 mm < t ≤ 63 mm → 380 MPa
• 63 mm < t ≤ 150 mm → 355 MPa

Gangsteel maintains stable TMCP-controlled rolling to guarantee these values across wide plates.

Tensile Properties

S355MLO provides a tensile range of 470–630 MPa, allowing the material to perform well under high stress while maintaining elasticity.
This combination of strength and ductility reduces risk of deformation and improves safety in critical structures.

Ductility and Formability

With elongation ≥ 22%, S355MLO offers:

• Good cold forming
• Excellent edge bending behavior
• Low risk of cracking during fabrication

This makes it suitable for welded frames, curved offshore components, and formed structural parts.

Weldability of S355MLO

Because S355MLO has low carbon and low carbon equivalent (CEV), it provides exceptional weldability.

Typical CEV: 0.40–0.43 max

Advantages:

• Reduced preheating temperature
• Minimum risk of cold cracking
• Easy welding for thick plates
• Compatible with common welding methods (SMAW, GMAW, SAW, FCAW)

This is one of the strongest advantages of TMCP steels over normalized grades.

Delivery Condition (M – Thermomechanical Rolled)

S355MLO is delivered in TMCP condition, indicated by the letter M.

TMCP provides:

• High strength with refined grain structure
• Superior toughness at –40°C
• Lower carbon equivalent than normalized steel
• Lower residual stress
• Better weldability and cutting performance

Gangsteel uses controlled rolling and accelerated cooling to achieve consistent TMCP quality.

Applications of S355MLO

Because of its mechanical strength, toughness, and weldability, S355MLO is used in:

• Offshore platforms & jackets
• Subsea equipment
• Marine engineering structures
• Wind power tower sections
• Steel bridges and long-span structures
• Mining & heavy machinery frames
• Pressure-bearing low-temperature components

Its reliable low-temperature performance makes it a preferred material for cold-region engineering.

Gangsteel Supply Range for S355MLO

• Thickness:6–150 mm
• Width:1500–3200 mm
• Length:6000–12000 mm
• Certificates:EN 10204 3.1 / 3.2 (DNV, ABS, LR, BV optional)
• UT Testing:EN 10160 S1–S3
• Z-direction:Z15 / Z25 / Z35 available

Gangsteel provides complete MTC documentation, low-temperature test results, and TMCP rolling records.

 

 

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