Navigating the specifications of EN 10025 structural steel can be challenging when confronted with suffixes like +N, +AR, and M. While the base grade remains S355J2, these suffixes represent drastically different manufacturing processes.
Understanding the S355J2+N vs S355J2+AR vs S355J2M differences is essential for ensuring the structural integrity of your project, especially regarding weldability and toughness.
As a premier global steel manufacturer and direct supplier, GNEE specializes in the production and distribution of high-strength structural steel plates. With our own advanced rolling mills and heat treatment facilities, we provide fully certified S355J2 series steel tailored to your specific delivery requirements.
Whether you are a large-scale construction firm or a specialized engineering shop, GNEE offers the technical expertise and factory-direct pricing to keep your project on budget and up to code.
Core Differences Between S355J2+N, S355J2+AR and S355J2M – Basic Definition
All three grades belong to the S355 structural steel family:
- S355 → Minimum yield strength of 355 MPa
- J2 → Impact test at -20°C (≥27J)
Key Designation Meaning
S355J2+AR (As Rolled)
Supplied directly after hot rolling, without additional heat treatment
S355J2+N (Normalized)
Supplied after normalizing or normalized rolling
S355J2M (Thermomechanically Rolled)
Produced using thermomechanical controlled processing (TMCP)
👉 Core Insight:
The difference is primarily processing route, which determines performance.
Why are there three variants-S355J2+N, S355J2+AR, and S355J2M-under the same S355J2 grade?
The "J2" designation in S355J2 indicates that its impact toughness at -20°C complies with the requirements of EN 10025. However, its actual performance depends on…
Delivery Conditions
| Delivery Condition | Full English Name | Heat Treatment | Characteristics |
|---|---|---|---|
| S355J2+N | Normalised or Normalised Rolled | Normalised / Normalised Rolling | Uniform microstructure, stable mechanical properties, excellent weldability |
| S355J2+AR | As Rolled | As-rolled condition | Lower cost, larger performance fluctuation |
| S355J2M | Thermomechanically Rolled | TMCP (Thermomechanical Controlled Process) | High strength, high toughness, excellent low-temperature performance |
In engineering applications, selecting the wrong delivery condition will directly affect welding distortion, fatigue life, load-bearing capacity, low-temperature impact performance, and other factors. Therefore, understanding the differences between them is critical.
Core Differences Between S355J2+N, S355J2+AR and S355J2M – Mechanical Properties
Mechanical Comparison
| Property | S355J2+AR | S355J2+N | S355J2M |
|---|---|---|---|
| Yield Strength | ≥355 MPa | ≥355 MPa | ≥355 MPa |
| Tensile Strength | 470–630 MPa | 470–630 MPa | 470–630 MPa |
| Impact Test | -20°C ≥27J | -20°C ≥27J | -20°C ≥27J |
| Toughness Stability | Moderate | High | Very High |
| Ductility | Moderate | Good | Excellent |
👉 Key Insight:
Although nominal values are the same, S355J2M provides the best overall performance due to TMCP.
Core Differences Between S355J2+N, S355J2+AR and S355J2M – Chemical Composition
Typical Composition (%)
| Element | S355J2+AR | S355J2+N | S355J2M |
|---|---|---|---|
| C | ≤0.24 | ≤0.20 | ≤0.16 |
| Mn | ≤1.60 | ≤1.60 | ≤1.60 |
| Si | ≤0.55 | ≤0.55 | ≤0.50 |
| P | ≤0.025 | ≤0.025 | ≤0.020 |
| S | ≤0.025 | ≤0.025 | ≤0.015 |
| Nb/V/Ti | Optional | Optional | Micro-alloyed |
Composition Insight
S355J2M usually has:
- Lower carbon content
- Micro-alloying elements
- Better weldability
Heat Treatment Process and Performance Stability
| Item | S355J2+N | S355J2+AR | S355J2M |
|---|---|---|---|
| Heat Treatment | Normalized | As-rolled | Thermomechanical Controlled Processing (TMCP) |
| Performance Stability | ★★★★★ | ★★★ | ★★★★★ |
| Stress Distribution | Uniform | Non-uniform | Excellent |
| Low-temperature Impact | Excellent | Medium | Excellent (some grades can reach -50°C) |
Notes:
S355J2+N undergoes normalizing treatment, resulting in a more uniform grain structure. For this reason, it is widely used in structural engineering and is a specified material for many EPC projects.
S355J2+AR is not subjected to heat treatment; its properties depend on raw material quality and rolling process, which may introduce engineering risks. It is generally used for structures with low mechanical property requirements.
S355J2M is a TMCP material widely applied in advanced engineering, especially for trusses, bridges and pressure-bearing structures.
Defining the As-Rolled Condition: What is S355J2+AR?
The first step in the S355J2+N vs S355J2+AR vs S355J2M comparison is understanding the "+AR" or "As-Rolled" condition. In this state, the steel is hot-rolled to its final dimensions without any subsequent heat treatment. The final properties of the steel are determined by the temperature and the reduction during the rolling process.
S355J2+AR is often the most economical choice. However, because the cooling is not strictly controlled after rolling, the internal grain structure can be inconsistent, and internal stresses may remain within the plate. While it meets the minimum yield strength of 355 MPa, it is generally less suitable for complex cold forming or heavy welding compared to its normalized or thermo-mechanically rolled counterparts.
A view of the GNEE hot-rolling production line
What Does S355J2 AR Mean? What Are the Procurement Risks?
Many customers often ask:
What does S355J2 AR mean? Why is it cheaper than +N grade?
"AR" stands for As Rolled, meaning the product has not received any heat treatment and is only cooled simply after rolling.
This results in:
- Non-uniform grain structure
- Higher internal stress
- Greater distortion during welding
- Unstable impact toughness
- Significantly lower low-temperature performance compared to +N or M grade materials
Therefore, low cost is the biggest advantage of S355J2+AR, but it is also its greatest risk.
The use of S355J2+AR should be avoided for applications such as bridges, pressure structures, offshore platforms, and lifting equipment.
The Benefits of Normalizing: Understanding S355J2+N Steel
When comparing S355J2+N vs S355J2+AR, the "+N" stands for Normalized or Normalized Rolled. This is a heat treatment process where the steel is heated above its upper critical temperature and then cooled in still air. This process "resets" the grain structure, creating a much finer and more uniform crystal lattice.
The core advantage of S355J2+N is its reliability. The normalized condition ensures that the mechanical properties are consistent throughout the entire plate, regardless of thickness. This makes it the industry standard for load-bearing structures like bridges, high-rise buildings, and heavy machinery. If your project involves significant welding, S355J2+N is superior to +AR because the refined grain structure significantly reduces the risk of brittle fracture in the heat-affected zone (HAZ).
Thermo-Mechanical Rolling: The S355J2M Advantage
The "M" suffix in the S355J2+N vs S355J2+AR vs S355J2M comparison refers to Thermo-Mechanically Rolled steel (governed by EN 10025-4). Unlike normalizing, which is a separate heat treatment after rolling, thermo-mechanical rolling (TMCP) involves strictly controlled temperature and deformation rates during the rolling process itself.
The primary benefit of S355J2M (or S355M) is that it achieves high strength and toughness with a lower Carbon Equivalent Value (CEV) than S355J2+N. This lower carbon content makes the steel exceptionally easy to weld, often requiring little to no pre-heating even in thick sections. This is a game-changer for offshore platforms, shipbuilding, and large-scale wind tower fabrication where welding efficiency and weight reduction are critical.
A GNEE quality inspector using an ultrasonic testing device on an S355J2+N plate
Is the Higher Price of S355J2M Worth It?
S355J2M is produced using TMCP (Thermomechanical Controlled Processing) technology and offers significant advantages:
- Higher low-temperature toughness
- Smaller heat-affected zone during welding
- Better plate flatness
- Lower residual stress
If your project demands excellent weldability, tight deformation control, and reliable low-temperature performance, S355J2M is the optimal choice.
Core Differences Between S355J2+N, S355J2+AR and S355J2M – Applications
Application Comparison
S355J2+AR
- General construction
- Fabricated structures
- Low-stress components
S355J2+N
- Bridges
- Machinery
- Structural engineering
S355J2M
- Offshore structures
- Oil & gas platforms
- Wind towers
- High-performance engineering projects
| Material | Recommended Applications | Unrecommended Applications |
|---|---|---|
| S355J2+N | Structural members, bridges, low-temperature environments, heavy welded structures | Projects with extremely tight budgets |
| S355J2+AR | General supports, light structural parts, non-pressure components | Bridges, pressure equipment, low-temperature environments, heavy structures |
| S355J2M | Offshore platforms, high-welding-volume projects, low-temperature structures, key components | Cost-restricted projects |
Core Differences Between S355J2+N, S355J2+AR and S355J2M – Selection Guide
How to Choose
- Choose S355J2+AR → budget-sensitive, general applications
- Choose S355J2+N → standard engineering structures
- Choose S355J2M → high-performance, safety-critical projects
👉 Engineering Tip:
For thick plates, welding-intensive structures, or high-performance requirements, S355J2M is often the best choice.
Core Differences Between S355J2+N, S355J2+AR and S355J2M – Conclusion
In conclusion, the core differences between S355J2+N, S355J2+AR and S355J2M are primarily based on their manufacturing processes and resulting performance. S355J2+AR is a cost-effective option for basic applications, S355J2+N offers balanced performance for most structural needs, while S355J2M delivers superior mechanical properties and reliability for demanding engineering environments.
If you are selecting the right steel for your project, GNEE can provide expert guidance, certified materials, and fast global delivery.
Contact us today to get the best solution and quotation for S355J2+N, S355J2+AR and S355J2M steel plates-maximize performance and optimize your project cost!
What is the main difference in S355N vs S355J2+N?
S355N is a low-alloy, normalized steel with microalloying for enhanced toughness, while S355J2+N is a non-alloy, normalized steel for cost-effective general construction.
How do S355N and S355J2+N toughness compare?
Both offer ≥27 J at -20°C, but S355N's fine-grain structure and microalloying (Nb, V, Al) provide superior toughness for critical applications.
Which is better for welding, S355N or S355J2+N?
S355J2+N's simpler composition and lower phosphorus/nitrogen make it slightly easier to weld, though both have low CEV (≤0.43% and ≤0.45%).
What applications suit S355N vs S355J2+N?
S355N is ideal for high-load structures like bridges and cranes; S355J2+N suits general construction and buildings, similar to en 10025 3 s275n normalized structural steel plate.
How do S355N and S355J2+N costs compare?
S355N is 10-20% more expensive than S355J2+N due to microalloying and enhanced toughness.
What is the main difference between S355ML and S355J2?
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.
What is the difference between S355J2 and S355J2G3?
S355J2G3 is a non alloy structural steel with good weldability and mechanical properties, commonly used in the manufacture of components, mechanical parts, and equipment. In contrast, S355J2+N (EN 1.0577) is a product obtained by normalizing S355J2 steel, which has higher strength and toughness.
What is the difference between S355J2 and S355J2 N?
Difference between both:
S355J2 +AR steel plate and S355J2+ N steel plate differ primarily by the delivery condition when supplying, with S355J2+AR steel plate being delivered As Rolled, and S355J2+N steel plate being delivered after normalizing heating treatment.
