1. Basic Definition
P355GH is a type of steel plate for medium- and high-temperature pressure vessels under the European standard (EN). It belongs to the category of non-alloy steel and is designed for boilers, pressure vessels, and other pressure equipment. Its naming rules are as follows:
"P": Stands for European standard vessel plate.
"355": Represents the minimum yield strength of 355 MPa.
"GH": Indicates suitability for medium- and high-temperature environments or specific heat treatment.
2. Execution Standard and Delivery Status
The standard specification implemented is EN 10028-2, which is the European standard for steel plates for pressure vessels.
P355GH is usually delivered in the normalised or normalised rolling condition to ensure stable material properties.
3. Chemical Composition
The typical chemical composition of P355GH is as follows (mass %):
C (carbon): 0.10% to 0.22%
Si (silicon): ≤0.60%
Mn (manganese): 1.10% to 1.70%
P (phosphorus): ≤0.025%
S (sulfur): ≤0.010%
4. Mechanical Properties
Yield strength (Rp0.2): ≥355 MPa
Tensile strength (Rm): 470–630 MPa
Elongation (A5): ≥22% (when thickness ≤16 mm)
Impact toughness: ≥40 J at room temperature (Charpy V-notch impact test)
5. Advantages
P355GH offers high strength and toughness, enabling it to withstand high pressure and impact loads with excellent resistance to deformation and fracture.
It also exhibits high-temperature resistance, suitable for medium- and high-temperature environments (≤600°C), maintaining stable performance over long periods.
Corrosion resistance: Provides good resistance to various corrosive media (such as acids, alkalis, and salt solutions).
Welding performance: Features a small heat-affected zone and high-strength welded joints, reducing the risk of cracks.
6. Typical Application Areas
P355GH is used in the petrochemical industry for manufacturing reactors, heat exchangers, storage tanks, and oil pipelines.
In the power industry, it is applied in boiler ladles, high-temperature steam pipes, and pressurized components of power generation equipment.
It is also used in the metallurgy and energy sectors for blast furnace gas pipelines and high-temperature gas treatment equipment.
Furthermore, it is utilized in general-purpose pressure vessels, including medium- and low-pressure storage tanks and compressed air systems.
7. Benchmarking with Domestic Materials
P355GH does not have a direct equivalent grade in China, but its performance is close to Q345R (GB 713) or 16MnR (old national standard). Adjustments to composition and processing may be necessary depending on specific working conditions.
