S355MLO Steel EN 10025-4 High Strength Supplier

 

 

S355MLO Steel – EN 10025-4 High Strength Structural Steel

Professional Technical Introduction by Gangsteel

S355MLO is a thermomechanically rolled (TMCP) high-strength structural steel grade specified in EN 10025-4. It offers excellent strength-to-weight ratio, improved toughness at low temperatures, and superior weldability compared with conventional structural steels.
Gangsteel supplies S355MLO steel plates with strict control of chemical composition, rolling temperature, and mechanical properties to ensure optimal performance for offshore structures, bridges, pressure-bearing components, and heavy engineering applications.

What Is S355MLO Steel?

• Grade family:S355 (minimum yield strength 355 MPa)
• Standard:EN 10025-4: Thermomechanical rolled structural steels
• Designation breakdown:
  • S– Structural steel
  • 355– Minimum yield strength
  • M– TMCP delivery condition
  • L– Low-temperature toughness
  • O– Impact tested at –40°C

S355MLO is widely used when engineers require high strength, excellent weldability, and guaranteed Charpy V-notch impact performance at very low temperatures.

1. Chemical Composition (EN 10025-4)

Gangsteel ensures strict ladle analysis control.

Element	max (%)	Typical Notes
C	0.12	Low carbon for better weldability
Si	0.50	Deoxidation
Mn	1.70	Strengthening element
P	0.025	Controlled impurity
S	0.020	Controlled impurity
Nb	0.05	TMCP alloying
V	0.14	Optional micro-alloy
Ti	0.03	Grain refinement
Cu	0.30	Weather-resistance improvement (optional)

(Exact values depend on plate thickness; consult Gangsteel for detailed mill chemistry.)

 

2. Mechanical Properties

Guaranteed properties for structural applications.

Property	Requirement	Notes
Yield Strength (ReH)	355–420 MPa (depends on thickness)	High load-bearing capacity
Tensile Strength (Rm)	470–630 MPa	TMCP-controlled microstructure
Elongation (A5)	≥ 22%	Excellent ductility
Charpy Impact	27 J at –40°C	The “O” designation
Thickness Range	6–150 mm (Gangsteel available)	Wide dimensional capability

 

3. Delivery Condition (EN 10025-4)

Delivery Condition	Designation	Description
Thermomechanical Rolled	TMCP / M	Low-temperature controlled rolling for high strength and toughness
+ Inspection certificate	3.1 / 3.2	EN 10204 certificates available
Ultrasonic Testing	S1–S3 or EN 10160	Optional based on customer request
Additional requirements	Z-direction (Z15/Z25/Z35)	For through-thickness performance

Gangsteel delivers S355MLO plates strictly in TMCP condition unless additional heat treatment is specified by the client.

 

Key Features of S355MLO Supplied by Gangsteel

✔Excellent weldability

Low carbon equivalent (CEV) ensures reduced preheat and improved weld quality.

✔High toughness at –40°C

Suitable for cold-region offshore, marine, and structural applications.

✔Superior strength-to-weight ratio

Allows engineers to reduce thickness and save project cost.

✔Excellent dimensional consistency

TMCP rolling provides uniform plate structure and reduced residual stress.

✔Available in large-size plates

Gangsteel supplies wide and heavy plates for demanding steel structure projects.

Typical Applications

• Offshore platforms and subsea construction
• Oil & gas processing modules
• Heavy machinery and construction equipment
• Steel bridges and long-span structures
• Ship components and marine engineering
• Low-temperature storage tanks and pressure equipment
• Wind towers, transition pieces, and energy structures

S355MLO is often chosen by engineers who require strong, light, and low-temperature-resistant steel for critical structural parts.

 

Gangsteel Supply Range (Standard Production)

• Thickness:6–150 mm
• Width:up to 3200 mm
• Length:up to 12000 mm
• Cutting:plasma, laser, waterjet, bending, welding
• Certificates:EN 10204 3.1 / 3.2 (Lloyd’s, ABS, DNV, BV optional)

Gangsteel provides full traceability from steelmaking to final inspection, ensuring every plate meets EN 10025-4 requirements.

 

Conclusion

S355MLO steel (EN 10025-4) is an ideal material for demanding structural applications requiring high strength, low-temperature toughness, and outstanding weldability. With advanced TMCP technology and strict quality control, Gangsteel supplies S355MLO plates that meet the requirements of offshore, marine, engineering, and energy industries worldwide.

 

 

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