P355GH is a widely recognized pressure vessel steel grade explicitly specified in the European standard EN 10028-2, which regulates steels for pressure-bearing equipment. As a non-alloy, fine-grained structural steel, it exhibits excellent comprehensive performance, including superior toughness to resist brittle fracture, outstanding weldability compatible with various conventional welding processes, and reliable high-temperature resistance that sustains structural stability under medium-temperature operating conditions. These inherent advantages make it a preferred material for manufacturing pressure vessels, boilers, and related equipment in the petrochemical, power generation, and chemical industries.
Mechanical Properties
| Type | Thickness (mm) | Yield Strength MPa (min) |
Tensile Strength MPa |
Elongation % (min) |
Impact Energy (KV J) (min) |
||
|---|---|---|---|---|---|---|---|
| -20° | 0° | +20° | |||||
| Normalized | ≤ 16 |
355 | 510 - 650 | 21 | 27 | 34 | 40 |
| 16> to ≤40 | 345 | 510 - 650 | 21 | 27 | 34 | 40 | |
| 40> to ≤60 | 335 | 460 - 580 | 21 | 27 | 34 | 40 | |
| 60> to ≤100 | 315 | 490 - 630 | 21 | 27 | 34 | 40 | |
| 100> to ≤150 | 295 | 480 - 630 | 21 | 27 | 34 | 40 | |
| 150> to ≤250 | 280 | 470 - 630 | 21 | 27 | 34 | 40 | |
Chemical Composition
| C | 0.10 to 0.22 |
| Si | ≤0.60 |
| Mn | 0.10 to 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 |
| Vi | ≤0.02 |
Process Characteristics of P355GH Steel
P355GH steel features process advantages such as simplicity, high adaptability and stable quality, which are well-matched with its application in pressure-bearing equipment. Key process characteristics are as follows:
Simple Heat Treatment Process: The base material adopts a normalized heat treatment process (880–950°C heating + air cooling), without complex quenching or tempering steps. This process is easy to operate, low in cost, and can effectively refine grains and ensure stable mechanical properties.
Good Weld Process Compatibility: It is compatible with various conventional arc welding processes, with low preheating requirements. Thin plates can be welded directly at room temperature, and thick plates only need low-temperature preheating (80–150°C), reducing welding difficulty and improving production efficiency.
Excellent Forming Process Performance: Both hot and cold forming processes are feasible. Hot forming has a wide temperature range and good plasticity, facilitating rapid shaping; cold forming allows moderate deformation, and only needs preheating for large deformation, adapting to diverse component processing needs.
Stable Machining Process: Its uniform microstructure ensures stable cutting performance during machining, with small tool wear and high machining accuracy. It can be processed by turning, milling, drilling and other conventional processes, without special machining tools or parameters, suitable for mass production.
All processes are mature and standardized, ensuring consistent product quality and high industrial application feasibility.
P355GH Steel Applications
P355GH is a versatile pressure vessel steel compliant with European EN standards, widely applied in industries requiring stable performance under moderate to high temperatures and pressure. Its key applications are as follows:
Boiler Manufacturing: It is a core material for boiler pressure parts, such as drum shells, water wall tubes, superheater headers and downcomers. These components operate under long-term high-temperature (up to 400°C) and high-pressure conditions, and P355GH's excellent thermal fatigue resistance and weldability ensure safe and reliable operation, meeting the strict requirements of power plant and industrial boiler systems.
Pressure Vessels: It is extensively used to fabricate pressure vessels in petrochemical, chemical and pharmaceutical industries. These vessels store or transport media like oil, gas, chemicals and steam, where P355GH's stable mechanical properties and corrosion resistance prevent leakage and deformation, adapting to harsh working environments with alternating temperature and pressure.
Heat Exchangers: It serves as a key material for heat exchanger tubes, tube sheets and shells. Heat exchangers are critical for energy transfer in power generation, refrigeration and industrial processing. P355GH's good thermal conductivity and toughness ensure efficient heat exchange while withstanding thermal stress, reducing maintenance costs and extending service life.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
What is the impact energy requirement for P355GH?
For P355GH, the minimum Charpy V-notch impact energy is 30 J at 20°C. For low-temperature applications, the impact test is conducted at -20°C, and the impact energy should also meet the standard requirement to resist brittle fracture.
What is the thermal conductivity of P355GH?
The thermal conductivity of P355GH is about 45-50 W/(m·K) at room temperature. This good thermal conductivity makes it suitable for heat exchange equipment like heat exchangers and boilers, ensuring efficient heat transfer.
What is the difference between P355GH and Q355B?
P355GH is a pressure vessel steel (EN standard) with stricter toughness and weldability requirements for pressure applications. Q355B is a Chinese standard structural steel, mainly used for general structural engineering, with lower performance requirements.
Can P355GH be heat-treated?
Yes, P355GH can undergo heat treatments like normalization, annealing and tempering. Normalization improves its grain structure and toughness, while annealing reduces hardness and improves machinability for complex processing.
What is the yield strength of P355GH at high temperatures?
The yield strength of P355GH decreases with increasing temperature. At 300°C, its yield strength is about 280-300 MPa, and at 400°C, it drops to around 220-240 MPa, which must be considered in high-temperature design.
What are the testing requirements for P355GH delivery?
Delivery testing for P355GH includes chemical composition analysis, tensile test, yield strength test, elongation test, impact test and hardness test. Some orders may require additional tests like ultrasonic flaw detection.
How to store P355GH plates?
P355GH plates should be stored in a dry, well-ventilated warehouse to avoid moisture and corrosion. They should be placed on wooden supports to prevent contact with the ground, and covered with waterproof cloth if stored outdoors.
What is the maximum pressure P355GH can bear?
The maximum bearing pressure of P355GH depends on factors like thickness, operating temperature and structural design. Generally, it can bear medium pressure (1-10 MPa) in normal temperature and pressure vessel applications, subject to calculation and certification.
Is P355GH a normalized steel?
P355GH can be delivered in normalized condition, which is a common delivery state. Normalization involves heating the steel to 850-950°C, holding for a period, and cooling in air to refine grains and improve toughness and strength.
How to identify P355GH materials?
P355GH materials can be identified by checking the material certificate (including grade, standard, chemical composition and mechanical properties), surface marking (grade and manufacturer information), and conducting on-site chemical or mechanical tests if necessary.