S355ML Equivalent GB Q345E EN 10025-4 Steel Plate Supplier

S355ML Equivalent GB Q345E – EN 10025-4 Steel Plate

S355ML is a thermomechanically rolled high-strength structural steel grade under EN 10025-4, designed for low-temperature service and heavy structural applications. It offers excellent weldability, stable mechanical properties, and guaranteed −40°C impact toughness.
In the Chinese GB/T standard system, the closest equivalent grade to S355ML is Q345E.

Gangsteel supplies both S355ML and Q345E heavy steel plates with EN 10204 3.1 / 3.2 certificates and full traceability.

What Is the Equivalent Grade of S355ML?

The closest Chinese GB equivalent to S355ML is:

• GB/T 1591 — Q345E

Why Q345E?

• “E” indicates –40°C impact test, the same temperature class as S355ML
• Strength level is similar (355 MPa yield strength)
• Suitable for welded structural applications
• Similar chemical and mechanical requirements

Although not identical, Q345E is the accepted engineering equivalent for S355ML in the Chinese market.

Chemical Composition Comparison: S355ML vs Q345E

S355ML is generally cleaner and has a lower Carbon Equivalent due to TMCP technology.

Mechanical Properties Comparison

Delivery Conditions: TMCP vs Normalized

S355ML

• Delivered in TMCP (thermomechanically rolled)
• Finer grain structure
• Higher toughness
• Lower carbon equivalent
• Excellent weldability

Q345E

• Delivered as rolled or normalized
• Higher heat input sensitivity
• Slightly lower weld toughness

TMCP steels such as S355ML generally outperform conventional normalized grades in low-temperature and high-stress environments.

Low-Temperature Performance Comparison

Both grades are impact-tested at –40°C, which makes them suitable for cold-climate structures, offshore engineering, bridges, and pressure-bearing components.

However:

• S355ML provides more consistent toughness values
• Better resistance to brittle fracture
• More stable performance in thick plate sections

Applications of S355ML and Q345E

These two grades are used in similar engineering fields, including:

• Offshore structures and subsea equipment
• Steel bridges and heavy infrastructure
• Low-temperature pressure vessels
• Wind tower sections and energy structures
• Mining machinery and cranes
• Cold-climate industrial facilities

S355ML is preferred for international projects requiring EN 10025-4 compliance, while Q345E is commonly used for domestic Chinese engineering.

Gangsteel Supply Range

Gangsteel provides both S355ML and Q345E steel plates with the following specifications:

• 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 or GB/T 2970
• Z-direction properties:Z15 / Z25 / Z35 on request

Export-grade quality and full MTC documentation are provided for every plate.

Conclusion

S355ML is a high-performance low-temperature TMCP structural steel under EN 10025-4.
Its Chinese equivalent grade is Q345E, which matches the low-temperature requirements and general mechanical properties.
However, S355ML provides superior weldability, higher toughness, and better structural reliability due to TMCP processing.

Others relative propery of en 10025-4 S355ML