What is Tube 40x40 Black Steel Hollow Sections Square Tube?
Tube 40x40 black steel hollow sections are square-shaped steel tubes with a hollow interior, treated with a black oxide finish for enhanced corrosion resistance. The 40x40mm dimension refers to the outer side length, making it a versatile choice for structural and fabrication projects.
Tube 40x40 black steel hollow sections combine strength, durability, and aesthetics, making them popular in various industries. Here's a detailed breakdown:
- 40x40mm dimension: Outer side length of 40mm (square cross-section), with wall thickness ranging from 1.5mm to 5.0mm.
- Black steel finish: Achieved through black oxide coating or hot-dip blackening, providing basic corrosion protection and a sleek appearance.
- Hollow structure: Reduces weight while maintaining structural integrity, ideal for load-bearing applications.
- Material base: Typically made from mild carbon steel (Q235, S235JR, or equivalent grades) for optimal strength and weldability.
This product balances performance and cost-effectiveness, suitable for both indoor and outdoor applications.
Chemical Composition of 40x40 Black Steel Hollow Sections
The chemical composition of Tube 40x40 black steel hollow sections adheres to strict standards, ensuring consistent mechanical performance and weldability.
| Element | Content (Max, %) | Role in Performance |
|---|---|---|
| Carbon (C) | 0.20 | Enhances strength without compromising ductility |
| Silicon (Si) | 0.35 | Improves heat resistance and processability |
| Manganese (Mn) | 1.40 | Boosts tensile strength and hardenability |
| Phosphorus (P) | 0.045 | Controlled to avoid brittleness |
| Sulfur (S) | 0.045 | Minimized to prevent cracking during welding |
| Iron (Fe) | Balance | Main matrix material providing structural base |
The composition meets EN 10219 or GB/T 3091 standards, ensuring compatibility with global construction requirements.
Mechanical Properties of 40x40 Black Steel Square Tube
Tube 40x40 black steel hollow sections offer excellent mechanical properties, suitable for structural load-bearing and fabrication processes.
| Mechanical Property | Standard Value | Test Method |
|---|---|---|
| Yield Strength (MPa) | ≥ 235 | EN 10002-1 |
| Tensile Strength (MPa) | 375-500 | EN 10002-1 |
| Elongation (%) | ≥ 22 | EN 10002-1 |
| Impact Strength (J) | ≥ 27 (at -20°C) | EN 10045-1 |
| Weldability | Excellent (compatible with MIG/TIG welding) | EN ISO 15614 |
These properties ensure the tube can withstand bending, cutting, and welding without structural damage.
Standard Specifications & Sizes of 40x40 Black Steel Hollow Sections
GNEE STEEL provides Tube 40x40 black steel hollow sections in standardized sizes, with customization options available for specific projects.
| Specification | Parameter Range |
|---|---|
| Outer Side Length | 40mm (fixed) |
| Wall Thickness | 1.5mm, 2.0mm, 2.5mm, 3.0mm, 4.0mm, 5.0mm |
| Length | 6m (standard), 9m, 12m, or cut-to-length (500mm-12000mm) |
| Surface Finish | Black oxide coating (thickness: 5-10μm) |
| Straightness | ≤ 1mm/m |
| Tolerance | Side length: ±0.5mm; Thickness: ±10% |
| Packaging | Bundled with steel straps, wrapped in waterproof paper |
All dimensions comply with EN 10219 (European) or GB/T 3091 (Chinese) standards, ensuring global compatibility.
Key Applications of Tube 40x40 Black Steel Hollow Sections
Tube 40x40 black steel hollow sections are versatile, widely used across construction, machinery, and furniture industries:
- Construction industry:
Structural frames for lightweight buildings
Balustrades, handrails, and staircases
Scaffolding components and support structures
Partition walls and ceiling grids
- Machinery manufacturing:
Machine frames and bases
Conveyor systems and material handling equipment
Agricultural machinery components
- Furniture & display:
Office furniture frames (desks, shelves)
Retail display stands and exhibition booths
Outdoor furniture (park benches, pergolas)
- Other applications:
Automotive chassis components
Electrical cabinet frames
Signage structures
2026 Latest Price of Tube 40x40 Black Steel Hollow Sections
The price of Tube 40x40 Black Steel Hollow Sections Square Tube is influenced by raw material costs, wall thickness, and order quantity. GNEE STEEL's 2026 factory prices are as follows:
| Wall Thickness | Price per Meter (USD) | Price per Ton (USD) | Minimum Order Quantity |
|---|---|---|---|
| 1.5mm | $2.80 - $3.20 | $780 - $830 | 500 meters |
| 2.0mm | $3.50 - $3.90 | $810 - $860 | 500 meters |
| 2.5mm | $4.20 - $4.60 | $840 - $890 | 300 meters |
| 3.0mm | $4.90 - $5.30 | $870 - $920 | 300 meters |
| 4.0mm - 5.0mm | $6.30 - $7.50 | $900 - $950 | 200 meters |
Prices are subject to change based on carbon steel market fluctuations. For customized lengths or large orders, contact us for discounted quotes
Tube 40x40 Black Steel Hollow Sections Square Tube from GNEE STEEL offers an ideal combination of strength, versatility, and cost-effectiveness for construction, machinery, and furniture applications. With our 20 years of manufacturing experience, strict quality control, and competitive pricing, we are your reliable partner for high-quality black steel hollow sections.
Whether you need standard or customized 40x40 black steel square tubes, GNEE STEEL can provide tailored solutions to meet your project requirements. Contact us today to get the latest Tube 40x40 Black Steel Hollow Sections Square Tube quotation and technical support for your upcoming projects.
Square / Rectangular steel tube
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