S355J2H Steel: Properties and Key Applications
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Table Of Content
Table Of Content
S355J2H steel is a structural hollow section grade that falls under the category of low-carbon steel, specifically designed for use in construction and engineering applications. It is part of the S355 family, which is known for its high strength and excellent weldability. The primary alloying elements in S355J2H include carbon (C), manganese (Mn), and silicon (Si), with the following general composition:
| Element | Percentage Range (%) |
|---|---|
| Carbon (C) | 0.17 - 0.20 |
| Manganese (Mn) | 1.20 - 1.60 |
| Silicon (Si) | 0.10 - 0.40 |
| Phosphorus (P) | ≤ 0.035 |
| Sulfur (S) | ≤ 0.035 |
Key Characteristics and Properties
S355J2H is characterized by its high yield strength, which typically ranges from 355 MPa (51.5 ksi) to 470 MPa (68.2 ksi), making it suitable for load-bearing applications. Its toughness at low temperatures is another significant property, with a Charpy impact test value of at least 27 J at -20°C (-4°F). This steel grade is also known for its good ductility, allowing for deformation without fracture.
Advantages:
- High Strength: Provides excellent load-bearing capacity.
- Weldability: Suitable for various welding techniques, facilitating construction.
- Versatility: Can be used in a wide range of applications, from bridges to buildings.
Limitations:
- Corrosion Resistance: Moderate resistance, requiring protective coatings in aggressive environments.
- Not Suitable for High-Temperature Applications: Limited performance at elevated temperatures compared to alloy steels.
S355J2H holds a significant position in the market due to its balance of strength, weldability, and cost-effectiveness, making it a popular choice in structural applications.
Alternative Names, Standards, and Equivalents
| Standard Organization | Designation/Grade | Country/Region of Origin | Notes/Remarks |
|---|---|---|---|
| EN | S355J2H | Europe | Commonly used in structural applications |
| ASTM | A500 Grade B | USA | Similar mechanical properties but different chemical composition |
| DIN | 17100 St 52-3 | Germany | Closest equivalent with minor differences |
| JIS | G3106 SM490A | Japan | Comparable grade with different impact requirements |
| ISO | 630 | International | General standard for structural steels |
While S355J2H is often compared to other grades, subtle differences in chemical composition and mechanical properties can affect performance in specific applications. For instance, A500 Grade B has a lower manganese content, which may influence its toughness.
Key Properties
Chemical Composition
| Element | Percentage Range (%) |
|---|---|
| Carbon (C) | 0.17 - 0.20 |
| Manganese (Mn) | 1.20 - 1.60 |
| Silicon (Si) | 0.10 - 0.40 |
| Phosphorus (P) | ≤ 0.035 |
| Sulfur (S) | ≤ 0.035 |
The primary alloying elements in S355J2H play crucial roles in its properties:
- Carbon (C): Enhances strength and hardness.
- Manganese (Mn): Improves hardenability and toughness.
- Silicon (Si): Contributes to deoxidation during steelmaking and enhances strength.
Mechanical Properties
| Property | Condition/Temper | Typical Value/Range (Metric) | Typical Value/Range (Imperial) | Reference Standard for Test Method |
|---|---|---|---|---|
| Yield Strength (0.2% offset) | Normalized | 355 MPa | 51.5 ksi | EN 10002-1 |
| Tensile Strength | Normalized | 470 - 630 MPa | 68.2 - 91.5 ksi | EN 10002-1 |
| Elongation | Normalized | 20% | 20% | EN 10002-1 |
| Impact Strength | -20°C | ≥ 27 J | ≥ 20 ft-lbf | EN 10045 |
| Hardness (Brinell) | - | ≤ 200 HB | ≤ 200 HB | EN 10003 |
The combination of these mechanical properties makes S355J2H suitable for structural applications where high strength and toughness are required, such as in bridges and buildings.
Physical Properties
| Property | Condition/Temperature | Value (Metric) | Value (Imperial) |
|---|---|---|---|
| Density | - | 7850 kg/m³ | 0.284 lb/in³ |
| Melting Point | - | 1420 - 1540 °C | 2590 - 2800 °F |
| Thermal Conductivity | 20°C | 50 W/m·K | 29 BTU·in/(hr·ft²·°F) |
| Specific Heat Capacity | 20°C | 460 J/kg·K | 0.11 BTU/lb·°F |
| Coefficient of Thermal Expansion | 20-100°C | 12 x 10⁻⁶ /K | 6.67 x 10⁻⁶ /°F |
The density of S355J2H is significant for weight calculations in structural applications, while its thermal conductivity and specific heat capacity are important for applications involving heat transfer.
Corrosion Resistance
| Corrosive Agent | Concentration (%) | Temperature (°C/°F) | Resistance Rating | Notes |
|---|---|---|---|---|
| Atmospheric | - | Ambient | Fair | Requires protective coatings |
| Chlorides | - | Ambient | Poor | Susceptible to pitting corrosion |
| Acids | - | Ambient | Poor | Not recommended for acidic environments |
| Alkalis | - | Ambient | Fair | Moderate resistance |
S355J2H exhibits moderate corrosion resistance, making it suitable for many environments but requiring protective measures in aggressive conditions. Compared to stainless steels, S355J2H is less resistant to pitting and stress corrosion cracking, particularly in chloride-rich environments.
Heat Resistance
| Property/Limit | Temperature (°C) | Temperature (°F) | Remarks |
|---|---|---|---|
| Max Continuous Service Temp | 400 °C | 752 °F | Limited oxidation resistance |
| Max Intermittent Service Temp | 500 °C | 932 °F | Risk of scaling |
| Creep Strength Considerations | 300 °C | 572 °F | Begins to lose strength |
At elevated temperatures, S355J2H can experience oxidation and scaling, which can affect its structural integrity. It is not recommended for applications requiring high-temperature performance.
Fabrication Properties
Weldability
| Welding Process | Recommended Filler Metal (AWS Classification) | Typical Shielding Gas/Flux | Notes |
|---|---|---|---|
| MIG | ER70S-6 | Argon/CO2 | Good for thin sections |
| TIG | ER70S-2 | Argon | Excellent for precision work |
| SMAW | E7018 | - | Suitable for thicker sections |
S355J2H is known for its excellent weldability, making it suitable for various welding processes. Pre-heating may be required for thicker sections to avoid cracking.
Machinability
| Machining Parameter | [S355J2H] | [AISI 1212] | Notes/Tips |
|---|---|---|---|
| Relative Machinability Index | 60% | 100% | Moderate machinability |
| Typical Cutting Speed (Turning) | 80 m/min | 120 m/min | Use sharp tools |
S355J2H has moderate machinability, requiring appropriate tooling and cutting speeds to achieve optimal results.
Formability
S355J2H can be cold and hot formed, with good ductility allowing for bending and shaping. However, care must be taken to avoid work hardening, which can lead to cracking.
Heat Treatment
| Treatment Process | Temperature Range (°C/°F) | Typical Soaking Time | Cooling Method | Primary Purpose / Expected Result |
|---|---|---|---|---|
| Normalizing | 900-950 °C | 1-2 hours | Air | Refine grain structure |
| Annealing | 600-700 °C | 1-2 hours | Air | Improve ductility |
| Quenching & Tempering | 850-900 °C | 1-2 hours | Water/Oil | Increase strength |
Heat treatment processes such as normalizing and quenching can significantly alter the microstructure of S355J2H, enhancing its mechanical properties.
Typical Applications and End Uses
| Industry/Sector | Specific Application Example | Key Steel Properties Utilized in this Application | Reason for Selection (Brief) |
|---|---|---|---|
| Construction | Structural beams | High yield strength, weldability | Essential for load-bearing structures |
| Automotive | Chassis components | Toughness, ductility | Required for safety and performance |
| Oil & Gas | Pipelines | Corrosion resistance, strength | Critical for durability in harsh environments |
Other applications include:
- Bridges
- Industrial buildings
- Heavy machinery
S355J2H is often selected for its balance of strength and weldability, making it ideal for structural components in various industries.
Important Considerations, Selection Criteria, and Further Insights
| Feature/Property | [S355J2H] | [Alternative Grade 1] | [Alternative Grade 2] | Brief Pro/Con or Trade-off Note |
|---|---|---|---|---|
| Yield Strength | 355 MPa | 350 MPa | 360 MPa | Comparable strength |
| Corrosion Aspect | Fair | Good | Excellent | Trade-off for cost |
| Weldability | Excellent | Good | Fair | Important for construction |
| Machinability | Moderate | High | Low | Affects manufacturing cost |
| Approx. Relative Cost | Moderate | High | Low | Cost-effective for structural use |
| Typical Availability | High | Moderate | Low | Readily available in the market |
When selecting S355J2H, considerations include cost-effectiveness, availability, and specific application requirements. Its moderate corrosion resistance may necessitate protective coatings in certain environments, while its weldability makes it a preferred choice for structural applications.
In summary, S355J2H steel is a versatile and robust material that meets the demands of various engineering applications, providing a balance of strength, weldability, and cost-effectiveness.
