Both P355GH steel and P355NH pressure vessel steel plate are widely used European standard materials for pressure equipment. Although they share similar strength levels, they are produced under different standards and designed for different service conditions, especially in terms of temperature performance and steel structure.
Understanding the difference between these two grades is essential for selecting the right material for your project.
Standards Specification of P355GH steel and P355NH pressure vessel steel plate
| Item | P355GH Steel | P355NH Steel |
|---|---|---|
| Standard | EN 10028-2 | EN 10028-3 |
| Steel Type | Non-alloy steel | Fine-grained structural steel |
| Delivery Condition | Normalized | Normalized |
| Main Feature | High-temperature performance | Toughness and weldability |
The key difference is that P355GH is designed for elevated temperature service, while P355NH focuses more on toughness and structural stability.
Chemical Composition Comparison of P355GH and P355NH pressure vessel steel plate
P355GH Steel Composition (%)
| Element | Content |
|---|---|
| C | 0.10 – 0.22 |
| Si | ≤0.40 |
| Mn | 1.10 – 1.70 |
| P | ≤0.025 |
| S | ≤0.015 |
| Al | ≤0.020 |
| N | ≤0.012 |
| Cr | ≤0.30 |
| Cu | ≤0.30 |
| Mo | ≤0.08 |
| Nb | ≤0.020 |
| Ni | ≤0.30 |
| Ti | ≤0.03 |
| V | ≤0.02 |
P355NH Steel Composition (%)
| Element | Content |
|---|---|
| C | ≤0.18 |
| Si | ≤0.50 |
| Mn | 1.10 – 1.70 |
| P | ≤0.025 |
| S | ≤0.015 |
| Al | ≥0.020 |
| N | ≤0.012 |
| Cr | ≤0.31 |
| Cu | ≤0.30 |
| Mo | ≤0.08 |
| Nb | ≤0.05 |
| Ni | ≤0.50 |
| Ti | ≤0.03 |
| V | ≤0.10 |
| Nb+Ti+V | ≤0.12 |
P355NH contains more micro-alloying elements (Nb, V, Ti). This improves grain refinement, toughness, and resistance to brittle fracture. P355GH has a simpler composition, optimized for high-temperature stability
Mechanical properties of P355GH steel and P355NH pressure vessel steel plate
| Property | P355GH Steel | P355NH Steel |
|---|---|---|
| Yield Strength | ≥355 MPa | ≥355 MPa |
| Tensile Strength | 470–630 MPa | 490–630 MPa |
| Impact Requirement | Not mandatory | Required (toughness guaranteed) |
| Temperature Focus | High temperature | Normal/low temperature |
Application of P355GH steel and P355NH pressure vessel steel plate
P355GH Steel – High Temperature Applications
P355GH steel is mainly used in environments where elevated temperature resistance is required:
Industrial boilers
Heat exchangers
Steam pipelines
Pressure vessels operating at high temperatures
It performs well under continuous high-temperature service, making it ideal for thermal systems.
P355NH Steel – Pressure & Structural Safety
P355NH pressure vessel steel plate is designed for applications requiring strength, weldability, and toughness:
Pressure vessels and storage tanks
Oil and gas equipment
Chemical processing units
Power plant components
It is especially suitable for structures under pressure and dynamic loads, where toughness is critical.
Core of P355GH and P355NH pressure vessel steel
| Feature | P355GH | P355NH |
|---|---|---|
| Standard | EN 10028-2 | EN 10028-3 |
| Focus | High temperature | Toughness & weldability |
| Structure | Non-alloy | Fine-grained |
| Impact Resistance | Lower | Higher |
| Application | Thermal systems | Pressure vessels |
How to Choose Between P355GH and P355NH?
Choose P355GH if:
- Your project operates at high temperatures
- You need stable performance in boilers or heat exchangers
- Impact toughness is not a primary requirement
Choose P355NH if:
- Your project involves pressure vessels or structural loads
- You require good weldability and toughness
- Safety and resistance to brittle cracking are critical
In real-world engineering, material failure is often related to temperature mismatch or insufficient toughness, not just strength. That is why selecting between P355GH and P355NH steel must consider actual working conditions rather than just mechanical properties.
Although P355GH steel and P355NH pressure vessel steel plate have similar strength levels, they serve different purposes:
- P355GH → Best for high-temperature applications
- P355NH → Best for pressure vessels requiring toughness and weldability
Choosing the right material ensures long-term safety, performance, and cost efficiency.
If you are selecting between P355GH and P355NH steel, the right choice can significantly impact your project performance and safety.
We supply both grades with full certification, stable quality, and fast delivery.
Contact us today to get expert advice and the best quotation for your project.
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What is P355NH material?
P355NH steel is characterised by good weldability and high resistance to brittle cracking.
What is the difference between p355 and S355 steel?
Mechanical Properties: P355GH: Has a minimum yield strength of 355 MPa and is optimized for high-temperature environments in pressure vessels, but has lower toughness in cold conditions. S355J2: Also has a yield strength of 355 MPa but is optimized for structural applications requiring impact toughness.
What is the difference between S355H and s355nh?
Purpose: Similar to S355H, it is used for structural hollow sections, but the "N" indicates that the steel is normalized or normalized rolled, which improves its toughness and weldability by refining the grain structure.
What is the difference between P355GH and P355NH?
P355GH steel is used worldwide by fabricators of welded pressure vessels, industrial boilers and heat exchangers and is engineered to work well in elevated temperature service. P355NH steel is normalized weldable fine grain steel flats under EN 10028-3: 2009 standard.