Detailed introduction of S275JR steel plate and its applications in industry

Detailed introduction of S275JR steel plate and its applications in industry

Below is a detailed English introduction to the European standard steel plate S275JR, including its chemical composition and mechanical properties presented in tables.

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Introduction to S275JR Steel Plate

S275JR is a non-alloy structural steel grade specified under the European standard EN 10025-2, which outlines the technical delivery conditions for hot-rolled products of structural steels. This grade is widely used in construction, engineering, and manufacturing industries due to its excellent balance of strength, ductility, and weldability. The designation "S" stands for structural steel, "275" indicates the minimum yield strength in megapascals (MPa) for thicknesses up to 16 mm, and "JR" denotes that the steel is tested for impact properties at room temperature (20°C) with a minimum impact energy of 27 Joules.

S275JR is favored for its versatility and cost-effectiveness, making it suitable for a variety of applications, including building frameworks, bridges, machinery components, and general structural fabrications. Its properties ensure that it can withstand moderate loads while maintaining good formability and toughness. The steel is typically supplied in the as-rolled condition but can also be normalized or normalized-rolled depending on specific requirements.

The chemical composition of S275JR is carefully controlled to ensure consistency in performance, while its mechanical properties provide reliable strength and durability. Below, we outline the chemical composition and mechanical properties of S275JR in detail, followed by its key characteristics, applications, and advantages.

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Chemical Composition of S275JR

The chemical composition of S275JR is defined by EN 10025-2 and varies slightly depending on the product thickness. The following table provides the maximum permissible values for key elements:

| Element       | Maximum Content (%) |
|--------------------|-------------------------|
| Carbon (C)        | 0.24                   |
| Manganese (Mn)    | 1.60                    |
| Phosphorus (P)    | 0.045                   |
| Sulfur (S)        | 0.045                   |
| Silicon (Si)      | 0.55                    |
| Nitrogen (N)      | 0.012                   |
| Copper (Cu)     | 0.55                    |

Note: For thicknesses ≤ 40 mm, the maximum carbon content is 0.24%. For thicknesses > 40 mm, it may be slightly higher, typically up to 0.25%, depending on the manufacturer’s specifications.  
Copper content is optional and typically specified when enhanced corrosion resistance is required.

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Mechanical Properties of S275JR

The mechanical properties of S275JR depend on the thickness of the steel plate. The following table summarizes the key mechanical properties as per EN 10025-2:

| Property                     | Value                                                                 |
|----------------------------------|---------------------------------------------------------------------------|
| Minimum Yield Strength (ReH) | 275 MPa (for thickness ≤ 16 mm)<br>265 MPa (16 mm < thickness ≤ 40 mm)<br>255 MPa (40 mm < thickness ≤ 63 mm)<br>245 MPa (63 mm < thickness ≤ 80 mm)<br>235 MPa (80 mm < thickness ≤ 100 mm) |
| Tensile Strength (Rm)        | 410–560 MPa (for thickness ≤ 100 mm)                                      |
| Elongation (A)               | ≥ 23% (for thickness ≤ 40 mm, longitudinal)<br>≥ 22% (40 mm < thickness ≤ 63 mm)<br>≥ 21% (63 mm < thickness ≤ 100 mm) |
| Impact Test (Charpy V-notch) | 27 J at 20°C (JR designation)                                             |

Note: The yield strength decreases with increasing thickness due to the influence of rolling and cooling processes on the microstructure. Elongation values may vary slightly depending on the test direction (longitudinal or transverse).

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Key Characteristics of S275JR

1. Weldability : S275JR exhibits excellent weldability due to its low carbon content and controlled alloying elements, making it suitable for various welding techniques, including arc welding, without the need for preheating in most cases.
2. Formability : The steel’s good ductility allows it to be easily formed, bent, and shaped, which is advantageous for manufacturing complex components.
3. Toughness : The JR designation ensures adequate toughness at room temperature, sufficient for most structural applications in moderate climates.
4. Surface Quality : S275JR plates typically have a smooth surface finish, suitable for painting or coating to enhance corrosion resistance.
5. Cost-Effectiveness : As a non-alloy steel, S275JR is relatively inexpensive compared to higher-grade or alloyed steels, offering a good balance of performance and economy.

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Applications of S275JR

S275JR is used in a wide range of industries due to its reliable mechanical properties and versatility. Common applications include:

- Construction : Structural beams, columns, and frameworks for buildings and bridges.
- Engineering : Components for machinery, cranes, and heavy equipment.
- Manufacturing : Fabrication of storage tanks, silos, and conveyor systems.
- Infrastructure : Railings, supports, and other elements in transportation and utility projects.
- General Fabrication : Plates, sections, and profiles for miscellaneous structural purposes.

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Advantages of S275JR

- Balanced Properties : Offers a combination of strength, toughness, and ductility suitable for diverse applications.
- Ease of Processing : Can be cut, welded, and formed with standard equipment, reducing fabrication costs.
- Compliance with Standards : Meets stringent European standards, ensuring quality and reliability.
- Availability : Widely available in various thicknesses and dimensions, making it easy to source for projects.

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Limitations of S275JR

While S275JR is highly versatile, it has some limitations:
- Corrosion Resistance : As a non-alloy steel, it is not inherently corrosion-resistant and may require coatings or galvanizing for outdoor use.
- Temperature Performance : The JR designation indicates testing at 20°C, so it may not be suitable for low-temperature applications without additional testing (e.g., J0 or J2 grades).
- Strength Limitations : For applications requiring higher strength, grades like S355 or higher may be preferred.

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Conclusion

S275JR is a reliable and widely used structural steel grade that meets the needs of numerous industries due to its excellent mechanical properties, weldability, and cost-effectiveness. Its compliance with EN 10025-2 ensures consistent quality, making it a preferred choice for construction and engineering projects. By understanding its chemical composition and mechanical properties, engineers and fabricators can effectively utilize S275JR in designs that demand strength, durability, and ease of processing.

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This introduction provides a comprehensive overview of S275JR steel plate, with its chemical and mechanical properties clearly presented in tables for easy reference. If you need further details or specific information, please let me know!