S355J2 seamless square tube Sizes: What’s Available in the Market?

2025-10-26 07:57:29

S355J2 seamless square tube Sizes: Market Availability and Specifications

Introduction

S355J2 is a European standard structural steel grade known for its excellent mechanical properties, weldability, and impact resistance at low temperatures. Seamless square tubes made from S355J2 are widely used in construction, mechanical engineering, and structural applications due to their high strength and durability.

This article provides a comprehensive overview of the available sizes of S355J2 seamless square tubes in the market, including dimensions, wall thicknesses, and relevant standards.

---

1. Understanding S355J2 Steel

1.1 Chemical Composition

S355J2 steel is a non-alloy structural steel with the following typical chemical composition (EN 10210-1):

- Carbon (C): ≤ 0.22%

- Silicon (Si): ≤ 0.55%

- Manganese (Mn): ≤ 1.60%

- Phosphorus (P): ≤ 0.035%

- Sulfur (S): ≤ 0.035%

1.2 Mechanical Properties

- Yield Strength (Re): ≥ 355 MPa

- Tensile Strength (Rm): 470–630 MPa

- Elongation (A): ≥ 22%

- Impact Toughness (KV at -20°C): ≥ 27 J

1.3 Applications

S355J2 seamless square tubes are used in:

- Structural frameworks

- Machinery components

- Offshore and marine structures

- Heavy-duty construction

---

2. Standard Dimensions of S355J2 Seamless Square Tubes

Seamless square tubes are manufactured according to EN 10210-1 (hot-finished) and EN 10216-1 (cold-finished). The available sizes vary based on production capabilities and market demand.

2.1 Common Outer Dimensions (Width × Height)

S355J2 seamless square tubes are available in the following standard sizes (in millimeters):

| Side Length (mm) | Wall Thickness Range (mm) |

|----------------------|-------------------------------|

| 20 × 20 | 2.0 – 5.0 |

| 25 × 25 | 2.0 – 6.0 |

| 30 × 30 | 2.5 – 8.0 |

| 40 × 40 | 3.0 – 10.0 |

| 50 × 50 | 3.0 – 12.0 |

| 60 × 60 | 4.0 – 15.0 |

| 80 × 80 | 5.0 – 20.0 |

| 100 × 100 | 6.0 – 25.0 |

| 120 × 120 | 8.0 – 30.0 |

| 150 × 150 | 10.0 – 40.0 |

| 200 × 200 | 12.0 – 50.0 |

2.2 Wall Thickness Variations

The wall thickness of seamless square tubes depends on the application:

- Thin-walled tubes (2–5 mm): Used in lightweight structures.

- Medium-walled tubes (5–12 mm): Common in general construction.

- Thick-walled tubes (12–50 mm): Used in heavy-duty and high-stress applications.

2.3 Length Options

Standard lengths for seamless square tubes include:

- Fixed lengths: 6m, 12m (most common)

- Random lengths: 4–14m (custom orders)

---

3. Manufacturing and Quality Standards

3.1 Key Standards

- EN 10210-1: Hot-finished structural hollow sections.

- EN 10216-1: Seamless steel tubes for pressure purposes.

- ASTM A500: U.S. standard for structural tubing (similar applications).

3.2 Production Process

1. Billet Heating: Steel billets are heated to high temperatures.

2. Piercing & Rolling: The billet is pierced and rolled into a seamless tube.

3. Sizing & Shaping: The tube is shaped into a square profile.

4. Heat Treatment: Normalizing improves mechanical properties.

5. Testing & Inspection: Ultrasonic, hydrostatic, and mechanical tests ensure quality.

---

4. Market Availability and Customization

4.1 Stock Availability

Most suppliers stock standard sizes (e.g., 50×50×5mm, 100×100×10mm). Larger or thicker tubes may require custom orders.

4.2 Custom Sizes

Manufacturers can produce tubes with:

- Non-standard dimensions (e.g., 35×35mm, 70×70mm)

- Special wall thicknesses (upon request)

- Precision-cut lengths (for specific projects)

4.3 Surface Treatments

- Black (as-rolled): Standard finish.

- Galvanized: For corrosion resistance.

- Painted/Powder-coated: Aesthetic and protective finishes.

---

5. Selection Guide for Buyers

5.1 Factors to Consider

- Load requirements: Thicker walls for higher stress.

- Environmental conditions: Galvanized for outdoor use.

- Weldability: S355J2 has good welding properties.

5.2 Common Mistakes to Avoid

- Choosing undersized tubes for heavy loads.

- Ignoring corrosion protection in harsh environments.

- Overlooking certification (EN 10210 compliance).

---

6. Conclusion

S355J2 seamless square tubes are available in a wide range of sizes, from small (20×20mm) to large (200×200mm), with varying wall thicknesses to suit different structural needs. Buyers should verify dimensions, mechanical properties, and certifications before purchasing. Custom sizes and finishes are also available for specialized applications.

By understanding the available options, engineers and contractors can select the most suitable S355J2 seamless square tubes for their projects, ensuring durability and performance.

---

This guide provides a detailed overview of S355J2 seamless square tube sizes in the market, helping buyers make informed decisions. For specific requirements, consulting with manufacturers or suppliers is recommended.