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

Element	S355ML (max %)	Q345E (max %)	Notes
C	0.12	0.20	S355ML typically has lower carbon
Mn	1.70	1.70	Similar strengthening element
P	0.025	0.025	Same limit
S	0.020	0.020	Same limit
Nb/V/Ti	Allowed	Allowed	Both use micro-alloying
CEV	0.40–0.43	0.45–0.52	S355ML has better weldability

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

Mechanical Properties Comparison

Mechanical Property	S355ML	Q345E	Notes
Yield Strength	355–420 MPa	345–390 MPa	S355ML slightly higher in thin plates
Tensile Strength	470–630 MPa	470–630 MPa	Very similar
Elongation	≥ 22%	≥ 20%	S355ML offers better ductility
Impact Toughness	27 J at –40°C	27 J at –40°C	Same temperature class
Delivery Condition	TMCP (M)	Normalized / rolled	Major difference

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.

 

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