Pressure Vessel Steel Plate--P355GH

P355GH is a fine-grained, normalized pressure vessel steel with excellent weldability and high toughness at low temperatures, specifically designed for manufacturing pressure-bearing components of boilers, pressure vessels and heat exchangers that operate under moderate to high temperature conditions. It conforms to European EN standards, featuring stable mechanical properties and good resistance to thermal fatigue, making it a widely used structural material in the petrochemical, power generation and industrial processing industries.

Mechanical Properties of EN 10028 – P355GH

Chemical Composition of EN 10028 – P355GH

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.

P355GH Steel Application Conditions

P355GH is engineered for steady performance under specific thermal and pressure conditions, with its application scope strictly matched to its material properties. Key application conditions are as follows:

Temperature Range: It is primarily used in moderate to high-temperature working environments, with a continuous operating temperature of -20°C to 400°C. The steel maintains excellent toughness at low temperatures to avoid brittle fracture, and its structural stability and mechanical strength remain uncompromised under long-term high-temperature heating, without obvious performance degradation caused by thermal aging.

Pressure Bearing Requirements: Suitable for medium and high-pressure working conditions of pressure-bearing equipment, adapting to the pressure fluctuations in industrial systems such as boilers and pressure vessels. It can bear stable design pressure and resist instantaneous pressure shocks, meeting the pressure resistance standards of European EN pressure vessel steel for static and dynamic load-bearing scenarios.

Working Medium & Environment: Applicable to equipment in contact with common industrial media including water, steam, oil, natural gas and general chemical fluids. It has good resistance to mild corrosive media and thermal fatigue caused by alternating cold and heat, and is suitable for dry, humid and other conventional industrial working environments (excluding strong acid, strong alkali and other severe corrosive conditions).

Welding & Fabrication Condition: It is used in welded structural components of pressure equipment, requiring conventional arc welding processes and no complex preheating or post-weld heat treatment under normal fabrication conditions, which is compatible with standard industrial production and processing requirements of pressure-bearing parts.

P355GH Steel Processing Properties & Operations

Hot Working: Suited for standard hot forming processes including rolling, forging and bending, with an optimal working temperature range of 850–1100°C. It exhibits good plastic deformability at this range, enabling smooth shaping into pressure vessel heads, shells and structural components; post-forming air cooling is typically adopted to retain its fine-grained microstructure and mechanical stability.

Cold Working: Can be subjected to moderate cold bending, flanging and shearing operations for precision component fabrication. Minor cold deformation requires no preheating, while for deformation exceeding 10%, low-temperature preheating (150–250°C) is recommended to prevent cold cracking and residual stress accumulation in the material.

Welding: Boasts excellent weldability for common arc welding processes (MIG/MAG, TIG, SMAW). No preheating is needed for thin plates (≤16mm) under normal ambient temperatures; for thick plates (>16mm) or low-temperature working environments, preheating to 80–150°C is advised to avoid hydrogen-induced cracking. Post-weld heat treatment is generally unnecessary for general structures, only required for heavy-walled high-pressure components.

Machining: Demonstrates good machinability for turning, milling, drilling and tapping operations. Its uniform microstructure reduces tool wear during processing, ensuring high surface finish and dimensional accuracy of machined pressure-bearing parts, matching standard industrial machining parameter requirements.

Heat Treatment: The base material is supplied in a normalized state (heating to 880–950°C, holding and air cooling) to achieve optimal toughness and strength. For special application requirements, stress relief annealing (550–650°C) can be performed post-fabrication to eliminate internal stress and improve structural stability of welded components.

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What is P355GH?

P355GH is a pressure vessel steel grade specified in EN 10028-2. It is a non-alloy, fine-grain structural steel with good toughness, weldability and high-temperature resistance, widely used in pressure vessel manufacturing.

Which standard defines P355GH?

P355GH is defined by the European standard EN 10028-2, which specifies technical delivery conditions for non-alloy and alloy steels for pressure purposes, covering chemical composition, mechanical properties and testing requirements.

What are the main chemical compositions of P355GH?

The main chemical compositions of P355GH include C (≤0.20%), Si (≤0.55%), Mn (1.00-1.60%), P (≤0.025%), S (≤0.015%), and trace elements like N, Cu, Ni, Cr, Mo to ensure its performance.

What are the minimum mechanical properties of P355GH?

P355GH has a minimum yield strength of 355 MPa (at 16-40 mm thickness), minimum tensile strength of 470-630 MPa, minimum elongation of 21%, and good impact toughness at room and low temperatures.

What is the maximum operating temperature of P355GH?

The maximum continuous operating temperature of P355GH is typically around 400-450°C. Beyond this range, its mechanical properties may degrade, affecting the safety and service life of pressure vessels.

Is P355GH weldable?

Yes, P355GH has excellent weldability. It can be welded using common methods like arc welding, gas welding and resistance welding, with proper preheating (if needed) and post-weld heat treatment to avoid cracks.

What preheating temperature is required for P355GH welding?

The preheating temperature for P355GH welding usually ranges from 80-150°C, depending on the material thickness, welding method and ambient temperature. Preheating prevents cold cracking and improves weld quality.

What are the common applications of P355GH?

P355GH is widely used in manufacturing pressure vessels, boilers, heat exchangers, pipelines and storage tanks that operate under medium temperature and pressure, such as in petrochemical, power generation and chemical industries.

Can P355GH be used in low-temperature environments?

P355GH has good low-temperature toughness, generally suitable for environments above -20°C. For lower temperatures, it needs to pass impact tests to ensure it can resist brittle fracture and meet application requirements.

What is the difference between P355GH and P355NH?

The main difference lies in toughness requirements. P355NH is normalized steel with higher notch toughness at low temperatures (-20°C), while P355GH is hot-rolled or normalized steel, suitable for medium-temperature pressure applications.