S355J2 vs S355ML EN 10025-4 Steel Plate Supplier

 

 

S355ML vs S355J2 EN 10025-4 Strength Comparison Supplier

Gangsteel – China's Leading Mill-Direct Supplier & Exporter of S355ML vs S355J2 EN 10025-4 Strength Comparison Steel Plates

Gangsteel is the professional supplier you can trust for both S355ML (EN 10025-4 TMCP) and S355J2 (EN 10025-2 hot rolled) 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 both grades with Z35 through-thickness quality in stock, 100 % UT EN 10160 S2/E2 standard, and full documentation.

Explore our complete en 10025 4 High Strength Structural Steel series for all grades.

 

S355ML vs S355J2 – The Complete Strength & Performance Comparison

S355ML (EN 10025-4 TMCP) and S355J2 (EN 10025-2 hot rolled) are the two most commonly compared grades when engineers look for 355 MPa yield strength steel. Both have identical nominal yield and tensile strength, but differ significantly in delivery condition, low-temperature toughness, weldability, and overall performance in demanding applications.

Property	S355J2 (EN 10025-2)	S355ML (EN 10025-4 TMCP)	Winner & Reason
Delivery Condition	Hot rolled (as-rolled or normalized rolled possible)	Thermomechanical rolled (TMCP)	S355ML – lower residual stress, better flatness
Minimum Yield Strength ReH (MPa)	355 (≤16 mm) → 275 (>100 mm)	355 (≤16 mm) → 295–305 (>100 mm)	S355ML – much better thick plate strength
Tensile Strength Rm (MPa)	470–630 (all thicknesses)	470–630 (≤100 mm) → 450–610 (>100 mm)	Tie – same range
Elongation A5 min (%)	22	22	Tie
Impact Toughness (long.)	≥27 J at –20 °C	≥27 J at –50 °C	S355ML – far superior low-temp performance
CEV max	0.45–0.47 (depending on thickness)	0.39	S355ML – significantly better weldability
Preheat-free Welding (mm)	Up to 30–40 mm	Up to 80–100 mm	S355ML – huge fabrication advantage
Residual Stress	Higher (hot rolled)	Very low (TMCP)	S355ML – less distortion, better fatigue
Through-Thickness (Z35)	Possible but more difficult	Excellent (standard in thick plates)	S355ML
Fatigue Life	Good	20-30 % better (finer grain, lower stress)	S355ML
Price (November 2025)	Baseline	+100–150 USD/ton	S355J2 cheaper, but S355ML better value
Market Share (Offshore Wind)	10–20 %	80–90 %	S355ML dominates

Bottom line: If your project temperature is above –20 °C and budget is tight → S355J2 is acceptable. If you need –40 °C or –50 °C design temperature, better weldability without preheat, better thick-plate strength, or longer fatigue life → S355ML is the clear winner and has become the default choice in 90 % of new offshore wind and cold-region projects.

For detailed grade designation, see S355ML Meaning EN 10025-4 Structural Steel Supplier.

 

Chemical Composition – The Key to Different Performance

Element	S355J2 (EN 10025-2) max %	S355ML (EN 10025-4) max %	Difference & Impact
C	0.20	0.14	Lower C in S355ML = much better weldability & HAZ toughness
Si	0.55	0.50	Similar
Mn	1.60	1.60	Same
P	0.025	0.025	Same
S	0.025	0.020	Slightly lower in S355ML
Nb + V + Ti	0.17 (combined)	0.20 (combined)	Higher microalloying in S355ML for finer grain
CEV max	0.45 (t≤150 mm)	0.39 (all thicknesses)	S355ML CEV 15-20 % lower → dramatically better weldability

The lower CEV and higher microalloying in S355ML are what give it the superior properties despite identical nominal strength.

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

 

Mechanical Properties – Thickness-by-Thickness Comparison

Thickness (mm)	S355J2 ReH min (MPa)	S355ML ReH min (MPa)	Difference
≤16	355	355	Same
>16 ≤40	345	345	Same
>40 ≤63	335	335	Same
>63 ≤100	315	315	Same
>100 ≤150	295	295–305	S355ML stronger
>150 ≤200	275–285	285–295	S355ML significantly stronger

In thick plates (>100 mm), S355ML maintains much higher yield strength thanks to TMCP.

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

 

Why 90 % of New Offshore Projects Choose S355ML Over S355J2

• 15–25 % weight reduction possible
• No preheating for thick welds → faster fabrication
• Superior HAZ toughness → higher safety margin
• Better fatigue performance in dynamic loading
• Lower lifetime cost despite higher initial price

 

Applications – Where Each Grade Excels

Application	Recommended Grade	Reason
Offshore wind towers	S355ML	Low-temp toughness, Z35, heavy welding
General building frames	S355J2	Cost-effective for normal conditions
Arctic oil & gas structures	S355ML	–50 °C impact mandatory
Standard bridges	S355J2	Adequate for –20 °C
Heavy cranes	S355ML	Better thick-plate strength

 

Why Choose Gangsteel for S355ML and S355J2 Plates

• Largest stock of both grades in Asia (8,000+ tons combined)
• Factory-direct price – 60–120 USD/ton lower than traders
• Full processing capability (cutting, beveling, drilling, rolling, priming)
• Z35 quality in stock for S355ML
• Immediate delivery worldwide
• Exported to 90+ countries with perfect documentation
• One-stop service – stock → processing → shipping

 

FAQ

Q1: What is the main difference between S355ML and S355J2?

A: S355ML is TMCP fine-grain steel with –50 °C impact toughness and much better weldability (CEV ≤0.39 vs S355J2 CEV up to 0.47). It also has better thick-plate strength and lower residual stress. S355J2 is traditional hot rolled steel with –20 °C impact.

Q2: Can I replace S355J2 with S355ML?

A: Yes – S355ML is a direct upgrade with better properties at a moderate price increase. Most engineers now specify S355ML as standard for new designs.

Q3: What is the price difference today?

A: S355ML is approximately 100–150 USD/ton higher than S355J2 (November 2025 market), but the weight saving and fabrication advantages usually make it cheaper overall.

Q4: Which one has better weldability?

A: S355ML – lower CEV and TMCP process give superior HAZ toughness and allow welding without preheating up to 80–100 mm thickness.

Q5: Which is better for offshore wind towers?

A: S355ML is now the industry standard for offshore wind (used in 90 % of new projects) due to –50 °C toughness and better fatigue performance.

Q6: Do you have both grades in stock?

A: Yes – very large stock of both S355J2 and S355ML in all common thicknesses, ready for immediate delivery.

Q7: Can you supply dual-certified plates?

A: Yes – many of our plates are dual-certified EN 10025-2 S355J2 and EN 10025-4 S355ML when the properties meet both standards.

 

Contact Gangsteel Today

Need S355ML 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 S355J2 and S355ML Plates.

(Word count: 1812)<|control12|># S355MLO vs S355ML EN 10025-4 Structural Supplier

Gangsteel – China's Leading Mill-Direct Supplier & Exporter of S355MLO and S355ML EN 10025-4 Structural Steel Plates

Gangsteel is the professional supplier for both S355ML (standard EN 10025-4) and S355MLO (offshore enhanced) structural steel plates, with the largest combined stock in Asia – over 6,000 tons ready for immediate delivery in thickness 6–200 mm, width 1500–4200 mm, length up to 18 m. All plates are genuine TMCP 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 S355ML.

For the grade meaning, see S355ML Meaning EN 10025-4 Structural Steel Supplier.

S355MLO vs S355ML – The Real Difference Explained

In the EN 10025-4 standard, S355ML is the official grade.

S355MLOis not a separate grade in the published EN 10025-4 standard.

"S355MLO" is a market designation used by mills and suppliers (especially for offshore applications) to indicate S355ML with additional offshore requirements, typically:

• Z35 through-thickness quality mandatory
• Higher impact energy (often ≥50 J average at –40 °C or –50 °C)
• CTOD (Crack Tip Opening Displacement) toughness testing
• Strain ageing test (impact after 5 % strain + ageing)
• PWHT (post-weld heat treatment) simulation testing
• Compliance with offshore standards like DNV-OS-B101, Norsok M-120, or API 2W

The base material is identical – same chemistry, same strength, same TMCP process.

The difference is only in the additional testing and guarantees required by offshore classification societies.

In short: S355ML = standard EN 10025-4 grade S355MLO = S355ML + offshore package ("O" for offshore)

Most modern offshore wind projects (Hornsea, Borkum Riffgrund, Formosa, Baltica) now specify S355MLO instead of plain S355ML to get the extra safety margin in welded joints.

Gangsteel supplies both standard S355ML and full S355MLO offshore-certified plates from stock.

For chemical details, see S355ML Chemical Composition EN 10025-4 Supplier.

Chemical Composition – Identical for Both

Both S355ML and S355MLO have exactly the same chemical requirements per EN 10025-4.

Element	C	Si	Mn	P	S	Nb	V	Al min	Ti	Cr	Ni	Mo	Cu	N	CEV max
S355ML / S355MLO	0.14	0.50	1.60	0.025	0.020	0.05	0.10	0.020	0.05	0.30	0.50	0.10	0.55	0.015	0.39

Typical Gangsteel actual values: C 0.09–0.12 %, CEV 0.34–0.37.

For S355MLO offshore packages, we can offer tighter controls (e.g., P+S ≤0.025 %, Ni 0.30–0.50 %) if required by the project specification.

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

Mechanical Properties – Standard vs Enhanced Requirements

Base mechanical properties are identical, but S355MLO has additional guarantees.

Property	S355ML (Standard)	S355MLO (Offshore Enhanced)	Notes
Yield Strength ReH (MPa)	355 (≤16 mm) → 285–295 (>150 mm)	Same + higher actual values (typically +20 MPa)	Same EN 10025-4 requirement
Tensile Strength Rm (MPa)	470–630	Same	Identical
Elongation A5 (%)	≥22	Same	Identical
Impact Toughness (long.)	≥27 J at –50 °C	≥50 J average at –40 °C or –50 °C + CTOD testing	The main enhancement
Z-quality	Z25 standard, Z35 optional	Z35 mandatory + higher RA (reduction of area)	Critical for offshore welds
CTOD Toughness	Not required	Required (≥0.25 mm at –10 °C or –40 °C typical)	Fracture mechanics for offshore
Strain Ageing Test	Not required	Often required (impact after strain + ageing)	Simulates fabrication effects

S355MLO plates from Gangsteel routinely achieve:

• Impact values 100–200 J at –50 °C
• CTOD 0.4–0.6 mm at –40 °C
• Z35 with ≥40 % reduction of area

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

Weldability – Both Excellent, S355MLO Superior in HAZ

Both grades have the same low CEV, but S355MLO's additional testing guarantees superior HAZ properties after high heat input welding.

No preheating required up to 80 mm for both grades. Gangsteel provides welding recommendations and heat-specific data for both S355ML and S355MLO.

Price Difference and Market Reality

Grade	Price Level (November 2025)	When to Choose
S355ML	Baseline	Standard structural, onshore, mild cold
S355MLO	+120–220 USD/ton	Offshore wind, oil & gas, Arctic, high-risk welds

The extra cost of S355MLO is easily justified by the additional safety margin and reduced risk of weld failure in offshore environments.

Why Choose Gangsteel for S355ML and S355MLO Plates

• Largest stock of both S355ML and S355MLO in Asia (6,000+ tons combined)
• Factory-direct price – 60–120 USD/ton lower than traders
• Full offshore certification packages for S355MLO in stock
• Z35 quality always available
• Immediate delivery worldwide
• Exported to 90+ countries with perfect documentation
• One-stop service – stock → processing → shipping

FAQ – Detailed Answers

Q1: Is S355MLO a separate grade in EN 10025-4?

A: No – it is S355ML with additional offshore requirements (higher impact, CTOD, Z35 mandatory). The base material is identical to S355ML, but the "O" designation indicates the extra testing package for offshore certification.

Q2: Can I use S355ML instead of S355MLO to save money?

A: Only if the project specification allows it. Most offshore wind and oil & gas projects now require the S355MLO package for the extra safety margin in welded joints, especially for monopiles and jacket nodes where CTOD toughness is critical.

Q3: What is the price difference between S355ML and S355MLO?

A: S355MLO is 120–220 USD/ton higher than standard S355ML (November 2025 market), depending on the exact testing package required (CTOD, strain ageing, higher impact energy).

Q4: Do you have S355MLO in stock right now?

A: Yes – very large stock of S355MLO with full offshore certification (CTOD, strain ageing, Z35) ready for immediate delivery. We can ship within 3–7 days worldwide.

Q5: What additional testing does S355MLO include?

A: Typical S355MLO package includes CTOD toughness testing (≥0.25 mm at –40 °C), strain ageing test (impact after 5 % strain + ageing at 250 °C/1h), higher impact energy (≥50 J average at –40 °C or –50 °C), Z35 mandatory, and PWHT simulation – all included in our S355MLO stock plates.

Q6: Is S355MLO required for all offshore projects?

A: Not all, but 90 % of new offshore wind projects and most oil & gas projects now specify S355MLO for critical welds. Plain S355ML is still accepted for non-critical areas or onshore applications.

Q7: Can you supply dual-certified plates?

A: Yes – many of our plates are supplied with both S355ML (EN 10025-4) and S355MLO offshore certification when the properties meet both standards.

Contact Gangsteel Today

Need S355ML or S355MLO 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 S355ML Plates.

 

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