S355MLO vs S355J2 EN 10025-4 Comparison Supplier

 

 

S355MLO vs S355J2 EN 10025-4 Steel Plate Comparison Supplier

Gangsteel – China's Leading Mill-Direct Supplier & Exporter of S355MLO vs S355J2 EN 10025 Steel Plates

Gangsteel is the professional supplier you can trust for both **S355MLO (EN 10025-4 offshore enhanced) and S355J2 (EN 10025-2) plates, with the largest combined stock in Asia – over 8,000 tons ready for immediate delivery in thickness 6–200 mm, width 1500–4200 mm, length up to 18 m. All plates are produced by top mills (HBIS, Shougang) with full European approvals and third-party inspection (DNV, ABS, LR, BV, CCS, KR, TÜV, SGS).

We supply S355MLO with full offshore certification package (CTOD, strain ageing, Z35 mandatory) in stock, alongside standard S355J2.

 

S355MLO vs S355J2 – The Complete Technical Comparison

S355MLO and S355J2 are both 355 MPa yield strength structural steels, but they are designed for very different applications and have significant differences in low-temperature toughness, weldability, and overall performance in demanding environments.

Property	S355J2 (EN 10025-2)	S355MLO (EN 10025-4 Offshore Enhanced)	Winner & Reason
Standard	EN 10025-2 (hot rolled structural)	EN 10025-4 TMCP + offshore package	S355MLO for modern offshore
Delivery Condition	Hot rolled or normalized rolled	Thermomechanical rolled (TMCP)	S355MLO – lower residual stress
Low-Temperature Toughness	≥27 J at –20 °C	≥50 J average at –40/–50 °C + CTOD testing	S355MLO – vastly superior for cold
CEV max	0.45–0.47	0.37 typical (enhanced)	S355MLO – dramatically better weldability
Preheat-free Welding (mm)	Up to 30–40 mm	Up to 100 mm	S355MLO – huge fabrication advantage
Through-Thickness (Z35)	Optional, more difficult	Mandatory + higher RA	S355MLO – essential for offshore welds
HAZ Toughness	Standard	Superior (finer grain + testing)	S355MLO
Fatigue Performance	Good	Excellent (lower stress + CTOD)	S355MLO
Price (November 2025)	Baseline	+200–300 USD/ton	S355J2 cheaper, S355MLO better value in offshore
Market Preference (Offshore Wind)	<10 %	>90 %	S355MLO dominates

Bottom line: S355J2 is a reliable, cost-effective grade for general structural applications where the lowest service temperature is above –20 °C.

S355MLO is the modern offshore grade that has almost completely replaced S355J2 in new offshore wind and oil & gas projects because of its superior low-temperature toughness, weldability, and through-thickness properties.

The price premium of S355MLO is easily recovered through:

• Reduced welding time (no preheat on thick plates)
• Lower distortion and rework
• Higher safety margin and longer service life
• Compliance with latest offshore standards

 

Chemical Composition – The Foundation of Different Performance

Element	S355J2 (EN 10025-2) max %	S355MLO (EN 10025-4 enhanced) max %	Difference & Impact
C	0.20	0.11 typical	Much lower C in S355MLO = superior HAZ toughness
Si	0.55	0.35 typical	Lower Si for better weldability
Mn	1.60	1.40 typical	Optimized for strength
P	0.025	≤0.015	Lower P for better toughness
S	0.025	≤0.008 (VD standard)	Ultra-low S for Z35 and CTOD
Nb + V + Ti	Limited	Higher controlled microalloying	Finer grain for superior properties

The significantly tighter chemistry in S355MLO (especially C, P, S) is what enables the enhanced offshore properties.

Full chemical data: S355ML Chemical Composition EN 10025-4 Supplier

 

Mechanical Properties – S355MLO Offshore Enhanced

Property	S355J2 (Standard)	S355MLO (Offshore Enhanced)	Notes
Yield Strength ReH (MPa)	355 (≤16 mm) → 275 (>100 mm)	355 (≤16 mm) → 305–315 (>100 mm)	S355MLO much better in thick plates
Tensile Strength Rm (MPa)	470–630	470–630	Same
Elongation A5 (%)	≥22	≥22	Same
Impact Toughness (long.)	≥27 J at –20 °C	≥50 J average at –40/–50 °C + CTOD	S355MLO vastly superior
Z35 Reduction of Area	Optional	Mandatory + ≥40 % typical	S355MLO essential for offshore welds

S355MLO plates from Gangsteel routinely achieve impact values 120–200 J at –50 °C and CTOD 0.45–0.65 mm at –40 °C.

Full mechanical data: S355ML Mechanical Properties EN 10025-4 Plate Supplier

 

Weldability – S355MLO Is Designed for Heavy Offshore Welding

S355MLO's lower CEV and enhanced testing make it the best choice for high heat input welding in offshore fabrication.

No preheating required up to 100 mm thickness for S355MLO vs only 30–40 mm for S355J2.

 

Price Difference and Market Reality

Grade	Price Level (November 2025)	When to Choose
S355J2	Baseline	Onshore, mild climate, budget projects
S355MLO	+200–300 USD/ton	Offshore wind, oil & gas, Arctic, high-risk welds

The extra cost of S355MLO is easily recovered through faster fabrication, lower distortion, and higher safety.

 

Why Choose Gangsteel for S355MLO and S355J2 Plates

• Largest stock of both grades in Asia (8,000+ tons combined)
• Factory-direct price – 60–120 USD/ton lower
• Full offshore certification for S355MLO in stock
• Immediate delivery worldwide
• Exported to 90+ countries

 

FAQ

Q1: Can I use S355J2 instead of S355MLO to save money?A: Not for offshore or low-temperature projects – the –20 °C impact toughness of S355J2 is insufficient for most modern offshore specifications.

Q2: What is the price difference?A: S355MLO is 200–300 USD/ton higher than S355J2, but the performance advantages make it the better choice for offshore projects.

Q3: Do you have S355MLO in stock?A: Yes – very large stock of S355MLO with full offshore certification ready for immediate delivery.

Q4: Can you supply both grades from the same heat for testing?A: Yes – we can supply dual-certified plates when properties meet both standards.

 

Contact Gangsteel Today

Need S355MLO or S355J2 plates? Contact us for quotation within 2 hours.

Email: admin@gangsteel.com WhatsApp/WeChat/Mobile: +86 135 9887 9167 Website: https://gangsteel.net/

Gangsteel – Your Expert for Both Standard and Offshore Grades.

 

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