S275JR Carbon Steel: Structural Steels (EN 10025 Series)
S275JR carbon steel, designated under the EN 10025-2 standard (yield strength of 275 MPa), is a non-alloy structural steel widely utilized in construction and engineering projects. With its hot-rolled form and balanced mechanical properties, it offers good weldability, machinability, and formability, making it ideal for load-bearing structures, bridges, and machinery components. This article explores its chemical composition, mechanical properties, production processes, applications, and performance benefits.
1. Core Chemical Composition (EN 10025-2 Standard)
| Element | Content Range | Function |
|---|---|---|
| Carbon (C) | ≤ 0.21% | Provides strength; controlled to ensure weldability without brittleness |
| Manganese (Mn) | 1.50 max (for t ≤ 16mm) | Improves strength, toughness, and hardenability; aids deoxidation |
| Phosphorus (P) | ≤ 0.040% | Limited to prevent brittleness and ensure ductility |
| Sulfur (S) | ≤ 0.040% | Controlled to avoid hot shortness and promote good hot working |
| Nitrogen (N) | ≤ 0.012% | Restricted to minimize strain aging and improve impact toughness |
| Copper (Cu) | ≤ 0.55% | Enhances corrosion resistance; limited in non-alloy grades |
2. Key Mechanical Properties (Room Temperature)
- Yield Strength (ReH): ≥ 275 MPa (for thickness ≤ 16mm; decreases slightly for thicker sections)
- Tensile Strength (Rm): 410-560 MPa (ensures high load capacity in structural applications)
- Elongation (A): ≥ 23% (longitudinal; provides adequate ductility for forming and bending)
- Impact Toughness (KV): ≥ 27 J at 20°C (Charpy V-notch; suitable for general structural use)
- Hardness (HB): ≤ 163 (typical for hot-rolled; facilitates machining and welding)
3. Manufacturing Process Characteristics
- Smelting: Basic oxygen furnace (BOF) or electric arc furnace (EAF) followed by ladle refining to achieve low impurity levels and consistent composition.
- Hot Rolling: Rolled at 900-1200°C into plates, sections, or bars; controlled cooling to refine grain structure and meet yield strength requirements.
- Normalization: Optional heat treatment at 850-900°C to homogenize microstructure, improve toughness, and relieve internal stresses.
- Cold Forming: For thinner sections, cold bending or drawing with annealing if needed to maintain properties without cracking.
- Surface Treatment: Shot blasting or pickling to remove scale; optional priming or galvanizing for corrosion protection in outdoor applications.
4. Typical Application Fields
Construction & Building
Structural beams, columns, and frameworks for buildings, bridges, and offshore platforms — compliant with Eurocode standards for load-bearing elements.
Machinery & Equipment
Heavy machinery frames, crane components, conveyor systems, and agricultural equipment — offers reliable strength in dynamic loading conditions.
Infrastructure Projects
Highway barriers, railway tracks, and tunnel supports — withstands environmental exposure with good fatigue resistance.
Piping & Fabrication
Pressure vessels, storage tanks, and welded pipes — suitable for moderate-pressure systems in industrial settings.
5. Difference from Similar Grades (S275JR vs S235JR vs S355JR)
| Grade | Yield Strength (MPa) | Key Advantage | Suitable Scenario |
|---|---|---|---|
| S275JR | ≥ 275 | Balanced strength and ductility; cost-effective | General structural fabrication (beams, plates up to 120mm thick) |
| S235JR | ≥ 235 | Higher formability; lower strength | Light-duty structures and non-critical components |
| S355JR | ≥ 355 | Superior strength for heavy loads | High-stress applications like cranes and large bridges |
6. Selection & Usage Precautions
- Environmental Considerations: Best for mild atmospheres; apply protective coatings (e.g., galvanizing) for corrosive environments like marine or industrial pollution.
- Welding Requirements: Preheat to 100-150°C for thicknesses >20mm; use matching electrodes (e.g., E7018); avoid high heat input to prevent cracking.
- Thickness Selection: Yield strength varies with thickness (e.g., 265 MPa for 16-40mm); consult EN 10025-2 tables for precise specifications.
- Quality Verification: Obtain material certificates (EN 10204 3.1) to verify composition, mechanical properties, and CE marking for structural compliance.
7. Get a Carbon Steel Quote
If you need customized S275JR carbon steel products (plates, sections, bars, or coils) or want to get a detailed price quote, please contact our team directly. Our specialists will provide professional technical support and competitive pricing based on your requirements.