Detailed introduction of S235JR steel plate and its applications in industry

Detailed introduction of S235JR steel plate and its applications in industry

Below is a detailed English introduction to S235JR steel plate, including its chemical composition and mechanical properties presented in tables.

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Detailed Introduction to S235JR Steel Plate

S235JR is a widely used non-alloy structural steel grade specified under the European standard EN 10025-2. It is one of the most common steel grades in construction, engineering, and manufacturing industries due to its excellent combination of strength, ductility, and weldability. The designation "S235JR" provides key information about its properties: "S" stands for structural steel, "235" indicates a minimum yield strength of 235 MPa, and "JR" signifies that the steel is suitable for room temperature applications with a specified impact energy of 27 Joules at 20°C.

S235JR steel plates are primarily used in general structural applications, such as buildings, bridges, machinery, and vehicle frameworks. Its versatility stems from its balanced mechanical properties, cost-effectiveness, and ease of processing, including cutting, forming, and welding. This grade is produced via hot rolling, which ensures uniformity in its microstructure and enhances its suitability for large-scale structural components.

The chemical composition of S235JR is carefully controlled to ensure consistent performance while maintaining affordability. It contains low levels of carbon and other alloying elements, making it a non-alloy steel with good machinability and formability. Additionally, S235JR exhibits satisfactory corrosion resistance for indoor or mildly corrosive environments, though it may require protective coatings for outdoor use in harsher conditions.

In terms of mechanical properties, S235JR offers a reliable yield strength and tensile strength, making it suitable for load-bearing applications. Its ductility allows it to undergo deformation without fracturing, which is critical for structural safety. The steel also complies with strict quality standards, ensuring its reliability in various engineering projects.

Below are detailed tables outlining the chemical composition and mechanical properties of S235JR steel plate based on the EN 10025-2 standard.

Chemical Composition of S235JR Steel Plate
The chemical composition is expressed as the maximum percentage by weight unless otherwise specified.

| Element         | Symbol | Maximum Content (%) |
|-----------------|--------|---------------------|
| Carbon          | C      | 0.17                |
| Silicon         | Si     | 0.35                |
| Manganese       | Mn     | 1.40                |
| Phosphorus      | P      | 0.045               |
| Sulfur          | S      | 0.045               |
| Nitrogen        | N      | 0.012 (if specified)|
| Copper          | Cu     | 0.55 (if specified) |

Notes:
- The exact composition may vary slightly depending on the manufacturer and thickness of the plate.
- For thicknesses greater than 40 mm, the carbon content may be adjusted to meet mechanical property requirements.

Mechanical Properties of S235JR Steel Plate
The mechanical properties depend on the thickness of the steel plate and are tested according to EN 10025-2.

| Property                | Thickness (mm) | Value                |
|-------------------------|----------------|----------------------|
| Minimum Yield Strength  | ≤ 16           | 235 MPa             |
|                         | > 16 ≤ 40      | 225 MPa             |
|                         | > 40 ≤ 63      | 215 MPa             |
|                         | > 63 ≤ 80      | 215 MPa             |
| Tensile Strength        | ≤ 100          | 360–510 MPa         |
|                         | > 100 ≤ 150    | 350–500 MPa         |
| Minimum Elongation      | ≤ 40           | 26% (longitudinal)  |
|                         | > 40 ≤ 63      | 25%                 |
|                         | > 63 ≤ 100     | 24%                 |
| Impact Energy (JR)      | At 20°C        | 27 Joules (minimum) |

Notes:
- Yield strength decreases as the thickness increases due to the influence of rolling and cooling processes.
- Elongation values are based on standard tensile testing and may vary slightly with test conditions.

Applications and Advantages
S235JR steel plates are favored in industries for their adaptability and cost efficiency. Common applications include:
- Construction: Beams, columns, and frameworks for buildings and bridges.
- Manufacturing: Components for machinery, agricultural equipment, and storage tanks.
- Infrastructure: Railings, platforms, and supports in civil engineering projects.

The key advantages of S235JR include its weldability without preheating (for thinner sections), good formability for shaping, and consistent quality that meets international standards. However, it is not designed for high-strength or low-temperature applications, where higher-grade steels like S275 or S355 may be preferred.

Conclusion
S235JR steel plate is a reliable and economical choice for a wide range of structural and engineering purposes. Its standardized chemical composition and mechanical properties ensure performance in moderate-strength applications, while its ease of fabrication makes it a staple in industrial production. For projects requiring specific certifications or enhanced properties, consultation with suppliers and adherence to EN 10025-2 guidelines are recommended.

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