Overview: What is 1.0345?
1.0345 is a material designation from the European standard EN 10216-1, which covers seamless steel tubes for pressure purposes.
Common Name: It is most commonly known as P235GH.
Type: It is a carbon-manganese steel.
Primary Use: It is specifically designed for pressure and high-temperature service, making it a classic "boiler steel" or "pressure vessel steel."
The number "1.0345" is the material number, while "P235GH" is the steel grade name. You will see them used interchangeably.
Key Specifications and Properties
The "P235GH" name breaks down as follows:
P: Stands for "Pressure" purpose.
235: Indicates the minimum specified yield strength (ReH) at room temperature is 235 MPa.
G: Stands for "Grain" controlled (achieved through Aluminum treatment, which refines the grain structure for better toughness).
H: Indicates suitability for High-temperature service.
Here are its key mechanical and chemical properties as per EN 10216-1:
Chemical Composition (Approximate % by weight):
| Element | Content (%) |
|---|---|
| Carbon (C) | max 0.16 |
| Manganese (Mn) | 0.80 - 1.20 |
| Silicon (Si) | 0.40 max |
| Phosphorus (P) | max 0.025 |
| Sulfur (S) | max 0.015 |
| Aluminum (Al) | min 0.020 (for grain control) |
The low carbon content ensures good weldability, while the manganese provides strength.
Mechanical Properties (at room temperature):
| Property | Value |
|---|---|
| Yield Strength (ReH), min | 235 MPa |
| Tensile Strength (Rm) | 360 - 510 MPa |
| Elongation (A), min | 25% |
High-Temperature Properties:
A key reason for its use in boilers is its ability to maintain strength at elevated temperatures. It has a defined minimum yield strength at elevated temperatures (e.g., still over 150 MPa at 300°C).
Common Applications
1.0345 / P235GH boiler tubes are used in systems where components are under internal pressure and often at high temperatures.
Power Generation Boilers: For both water tube and fire tube boilers.
Superheaters and Heat Exchangers: In sections with moderate temperatures and pressures.
Pressure Vessels: For various industrial processes.
Pipelines for Hot Water and Steam: In industrial plants and district heating systems.
Nuclear Power Plants: In auxiliary systems (not the core reactor pressure vessel).
Equivalent Grades in Other Standards
1.0345 / P235GH is a very common material, and it has direct or very close equivalents in other major international standards.
| Standard | Equivalent Grade | Note |
|---|---|---|
| ISO 9328-2 | P235GH | Direct equivalent |
| ASTM A192 / A210 | A192 | Very close; A192 is specifically for high-pressure boiler tubes. |
| DIN 17175 | St35.8 | A very similar and historically common German grade. |
| JIS G3461 | STB340 | Japanese standard for boiler and heat exchanger tubes. |
Note: While these grades are similar, they are not always chemically and mechanically identical. Substitution should only be done after consulting the relevant design codes and ensuring the material meets all required specifications for the application.
Manufacturing and Fabrication
Manufacturing Process: These pipes are typically seamless, meaning they are formed from a solid billet without a welded seam. This provides uniform strength and is crucial for high-pressure integrity.
Weldability: 1.0345 has excellent weldability due to its low carbon content. Common welding methods like SMAW (Stick), GTAW (TIG), and GMAW (MIG) can be used. Preheating is generally not required for thinner sections but should be assessed based on thickness and ambient conditions.
Forming: It has good cold-forming properties, allowing it to be bent and flanged during the fabrication of boiler systems.
Important Considerations
Not for Corrosive Environments: As a carbon steel, it has limited resistance to corrosion. In environments with oxygenated water or other corrosive elements, protective measures (like water treatment) or alternative materials (stainless steel) may be necessary.
Temperature Limit: While good for high temperatures, it has an upper temperature limit (typically around 450-500°C for long-term service). Beyond this, creep strength decreases significantly.
Quality and Certification: Always ensure the pipe supplier provides a mill test certificate (MTC) or EN 10204 3.1/3.2 certificate. This document verifies that the material has been tested and conforms to the EN 10216-1 standard.
Summary
1.0345 (P235GH) Carbon Steel Boiler Pipe is a reliable, cost-effective, and widely used material for constructing pressure parts in boilers, heat exchangers, and pressure vessels. Its excellent combination of strength, weldability, and high-temperature performance makes it a fundamental building block for the power and process industries.
When sourcing this material, always specify the full standard (e.g., EN 10216-1 P235GH) to ensure you receive the correct product for your application.
