What Are the Dimensions of Standard E235B Square Steel Pipe?

2025-10-21 08:09:11

Dimensions of Standard E235B square steel pipe

Introduction to Square Steel Pipes

Square steel pipes are hollow structural sections with equal width and height dimensions, forming a perfect square cross-section. These pipes are widely used in construction, mechanical engineering, automotive manufacturing, and various industrial applications due to their excellent mechanical properties and ease of fabrication. The E235B grade represents a specific quality standard for these steel pipes, indicating their chemical composition and mechanical characteristics.

Square steel pipes offer several advantages over other structural shapes, including uniform strength in all directions, aesthetic appeal, and efficient material distribution. Their hollow nature makes them lighter than solid bars while maintaining considerable strength, which is particularly valuable in weight-sensitive applications.

Understanding E235B Steel Grade

The E235B designation follows the European standard EN 10210 for hot-finished structural hollow sections. This classification system provides important information about the steel's properties:

- E235: Indicates the minimum yield strength of 235 MPa (Megapascals)

- B: Specifies the impact energy quality grade at room temperature

E235B steel contains controlled chemical composition with limited carbon, manganese, phosphorus, and sulfur content to ensure good weldability and formability. The "B" quality grade means the material has been tested for impact energy absorption at room temperature (20°C), making it suitable for structural applications where some toughness is required.

Standard Dimensions of E235B Square Pipes

The dimensions of standard E235B square steel pipes are typically specified by three main parameters:

1. Outside Dimensions (Width × Height): The external measurements of the square pipe

2. Wall Thickness: The thickness of the steel forming the pipe walls

3. Length: Standard pipe lengths, usually ranging from 6 to 12 meters

These dimensions follow international standards such as EN 10210 (European standard) and can vary slightly between different regional specifications. The most common size ranges are:

Common Size Ranges

- Small sizes: From 20×20 mm to 60×60 mm

- Medium sizes: From 70×70 mm to 120×120 mm

- Large sizes: From 140×140 mm to 300×300 mm and beyond

Wall Thickness Variations

Wall thickness typically ranges from 1.5 mm to 12 mm or more, depending on the pipe size and application requirements. Common thickness designations include:

- Light gauge: 1.5-3 mm

- Standard gauge: 3-6 mm

- Heavy gauge: 6-12 mm

- Extra heavy gauge: >12 mm

Detailed Dimension Tables

The following tables provide comprehensive dimension data for standard E235B square steel pipes:

Table 1: Small to Medium Square Pipe Dimensions (20×20 mm to 120×120 mm)

| Outside Dimensions (mm) | Wall Thickness Options (mm) | Theoretical Weight (kg/m) |

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

| 20×20 | 1.5, 2.0, 2.5, 3.0 | 0.84-1.57 |

| 30×30 | 1.5, 2.0, 2.5, 3.0 | 1.31-2.47 |

| 40×40 | 2.0, 2.5, 3.0, 4.0 | 2.29-4.38 |

| 50×50 | 2.0, 2.5, 3.0, 4.0, 5.0 | 2.93-6.95 |

| 60×60 | 2.5, 3.0, 4.0, 5.0, 6.0 | 4.44-9.59 |

| 70×70 | 3.0, 4.0, 5.0, 6.0 | 6.20-11.78 |

| 80×80 | 3.0, 4.0, 5.0, 6.0, 8.0 | 7.13-17.22 |

| 90×90 | 4.0, 5.0, 6.0, 8.0 | 10.47-20.09 |

| 100×100 | 4.0, 5.0, 6.0, 8.0, 10.0 | 11.73-27.48 |

| 120×120 | 5.0, 6.0, 8.0, 10.0 | 17.72-35.50 |

Table 2: Large Square Pipe Dimensions (140×140 mm to 300×300 mm)

| Outside Dimensions (mm) | Wall Thickness Options (mm) | Theoretical Weight (kg/m) |

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

| 140×140 | 5.0, 6.0, 8.0, 10.0 | 20.70-41.48 |

| 150×150 | 5.0, 6.0, 8.0, 10.0, 12.0 | 22.19-47.10 |

| 160×160 | 6.0, 8.0, 10.0, 12.0 | 28.35-55.30 |

| 180×180 | 6.0, 8.0, 10.0, 12.0, 14.0 | 32.00-72.60 |

| 200×200 | 6.0, 8.0, 10.0, 12.0, 14.0, 16.0 | 35.60-89.60 |

| 250×250 | 8.0, 10.0, 12.0, 14.0, 16.0 | 59.20-115.20 |

| 300×300 | 10.0, 12.0, 14.0, 16.0, 20.0 | 89.20-178.20 |

Manufacturing Tolerances

Standard E235B square pipes are manufactured with specific dimensional tolerances to ensure consistency and quality. These tolerances typically include:

Outside Dimension Tolerances

- For sizes ≤ 120 mm: ±0.5 mm to ±1.0 mm

- For sizes > 120 mm to 200 mm: ±1.0 mm to ±1.5 mm

- For sizes > 200 mm: ±1.5 mm to ±2.0 mm

Wall Thickness Tolerances

- For wall thickness ≤ 3 mm: ±10% of nominal thickness

- For wall thickness > 3 mm to 10 mm: ±8% of nominal thickness

- For wall thickness > 10 mm: ±7% of nominal thickness

Straightness Tolerances

Standard square pipes typically have a straightness tolerance of 0.2% of the length, with a maximum deviation specified for different length categories.

Mechanical Properties of E235B Square Pipes

The E235B grade ensures specific mechanical properties that are crucial for structural applications:

1. Yield Strength (ReH): Minimum 235 MPa

2. Tensile Strength (Rm): 360-510 MPa

3. Elongation at Break (A): Minimum 26% (for thickness ≤ 16 mm)

4. Impact Energy (KV): Minimum 27 J at +20°C (for quality grade B)

These properties make E235B square pipes suitable for load-bearing structures where moderate strength and good weldability are required.

Weight Calculations

The theoretical weight of square steel pipes can be calculated using the following formula:

Weight (kg/m) = [4 × (Outside Dimension - Wall Thickness) × Wall Thickness × Density] / 1000

Where:

- Outside Dimension and Wall Thickness are in millimeters

- Density of steel is typically 7.85 g/cm³

For example, a 50×50 mm square pipe with 3 mm wall thickness:

Weight = [4 × (50 - 3) × 3 × 7.85] / 1000 = 4.43 kg/m

Surface Treatment Options

Standard E235B square pipes are available with various surface treatments depending on application requirements:

1. Black (as manufactured): No additional treatment, suitable for indoor use or where corrosion isn't a concern

2. Hot-dip galvanized: Zinc coating for corrosion resistance in outdoor environments

3. Painted: Various paint systems for both protection and aesthetics

4. Powder coated: Durable finish with excellent corrosion resistance and color options

Applications of E235B Square Pipes

The dimensions and properties of E235B square pipes make them suitable for numerous applications:

1. Construction: Building frames, support structures, roofing systems

2. Industrial Equipment: Machine frames, conveyor systems, storage racks

3. Transportation: Vehicle chassis components, trailer frames

4. Furniture: Modern furniture frames, shelving systems

5. Infrastructure: Guardrails, sign supports, lighting poles

6. Agricultural Equipment: Greenhouse structures, machinery components

Comparison with Other Steel Grades

While E235B is a common choice, other steel grades may be selected based on specific requirements:

1. E235A: Similar strength but without impact testing requirements

2. E275B: Higher yield strength (275 MPa) with impact testing

3. E355B: Even higher strength (355 MPa) for more demanding applications

4. S235JR: Equivalent grade under different standards with similar properties

The choice between these grades depends on factors like required strength, toughness, weldability, and cost considerations.

International Standards and Equivalents

E235B square pipes correspond to various international standards:

1. EN 10210: Hot finished structural hollow sections

2. ASTM A500: Standard specification for cold-formed welded and seamless carbon steel structural tubing

3. JIS G3463: Japanese standard for square and rectangular carbon steel tubes

4. GB/T 6728: Chinese standard for cold-formed hollow structural sections

While dimensions may be similar across standards, material properties and testing requirements can vary.

Fabrication Considerations

When working with E235B square pipes, several fabrication aspects should be considered:

1. Cutting: Can be cut with saws, plasma cutters, or laser cutting systems

2. Welding: Excellent weldability with common methods (MIG, TIG, arc welding)

3. Bending: Possible with proper equipment, though radius depends on wall thickness

4. Drilling and Machining: Can be machined with standard tools, though harder grades may require special bits

Quality Control and Testing

Standard E235B square pipes undergo various quality control measures:

1. Dimensional Inspection: Verification of outside dimensions and wall thickness

2. Visual Inspection: Surface quality and straightness checks

3. Mechanical Testing: Tensile, yield strength, and elongation tests

4. Impact Testing: For quality grade B, Charpy V-notch tests at specified temperatures

5. Non-destructive Testing: Ultrasonic or eddy current testing for internal defects

Environmental Considerations

E235B square steel pipes offer several environmental benefits:

1. Recyclability: Steel is 100% recyclable without quality degradation

2. Durability: Long service life reduces replacement frequency

3. Efficient Material Use: Hollow sections use less material than solid bars for equivalent strength

4. Energy Efficiency: Potential for thermal breaks in building applications

Future Trends in Square Pipe Dimensions

The dimensions and specifications of square steel pipes continue to evolve with industry needs:

1. Thinner Walls with Higher Strength: Advanced steel grades allow reduced material use

2. Custom Sizes: Increasing demand for non-standard dimensions for specialized applications

3. Improved Tolerances: Tighter manufacturing controls enable more precise fabrication

4. Hybrid Materials: Combinations with other materials for enhanced properties

Conclusion

The dimensions of standard E235B square steel pipes cover a wide range of sizes and wall thicknesses to accommodate diverse structural and mechanical applications. Understanding these dimensions—from the common 20×20 mm small pipes to the large 300×300 mm structural sections—is essential for proper material selection and engineering design. The E235B grade offers an excellent balance of strength, weldability, and cost-effectiveness for many general-purpose applications.

When selecting square pipe dimensions, engineers must consider not just the nominal sizes but also the permitted tolerances, mechanical properties, and surface treatment options that affect performance in specific environments. The comprehensive dimension tables provided in this document serve as a valuable reference for professionals working with these versatile structural components.

As manufacturing technologies advance and material science progresses, we can expect continued refinement of square pipe dimensions and properties to meet the evolving needs of modern construction and industry. The standardization of these dimensions ensures compatibility across global markets while allowing for regional variations when required by specific applications or environmental conditions.