Introduction
Black Square Pipe refers to square steel pipes featuring a black or dark gray surface resulting from hot-dip blackening or galvanization. It was widely used in construction, steel structure engineering, and mechanical manufacturing.
| Tolerance | ±1% |
| Surface Treatment | black, galvanized Surface can be customized |
| Alloy Or Not | Non-Alloy |
| Oiled or Non-oiled | Non-oiled or as required |
| Out diameter | 30*30mm-200*400mm, can be customized |
| Technique | ERW or seamless, customizable |
| Thickness | 1.5mm-12mm, can be customized |
| Application | Structure Pipe, Construction, Steel structure engineering, Curtain wall construction etc. |
Features
- Strict Dimensional Tolerance
Length deviation of ±0.5 mm; wall thickness deviation of ±10%, guaranteeing precise fitting in applications.
- Dual Manufacturing Techniques
Available in ERW (electric resistance welding) or seamless manufacturing processes, meeting industrial quality standards and ensuring stable structural performance of the pipe body.
- High Strength
Engineered with a low carbon content (≤0.20%), this steel combines high strength and rigidity with excellent weldability and formability.
- Long Service lifespan
Black square pipes are often coated with anti-corrosive finishes or painted to extend their lifespan in outdoor or harsh environments.
Customization Options
- Steel Grade Customization
Mainstream carbon steel grades, including Q235, Q345, etc.
- Length Customization
Standard lengths cover 1-12 m (6 m/12 m are conventional standards), and non-standard lengths can be customized via professional laser-cutting technology.
- Surface Treatment
Customizable black oxide coating or galvanized surface treatment.
Mechanical properties
Tensile strength 520~680 MPa, wall thickness ≤ 16 mm, yield strength ≥ 420 MPa when the wall thickness is 16 mm to 30 mm, yield strength ≥ 400 MPa when the wall thickness is ≥ 30 mm, impact test Q420E, impact energy ≥ 27 J at -40°C.
Chemical composition: Carbon: ≤0.20, Silicon: ≤0.50, Manganese: ≤1.70, Phosphorus: ≤0.025, Sulfur: ≤0.020, Niobium: ≤0.07, Vanadium: ≤0.20, Titanium: ≤0.20, Chromium: ≤0.30, Nickel: ≤0.50, Copper: ≤0.20, Nitrogen: ≤0.015, Molybdenum: ≤0.20, Aluminum: ≥0.015.
FAQ
Q: How are Black Square Pipes packaged and stored before shipment?
A: Qualified pipes are packaged in wooden crates or bundles and stored in a moisture-controlled warehouse to avoid damage.
Q: What quality inspections are performed on Black Square Pipes?
A: Each pipe is tested for dimensional accuracy, weld strength, and coating adhesion using ultrasonic and pressure tests.
Q: How are Black Square Pipes formed and welded during production?
A: Steel coils are rolled into square shapes via cold forming, then welded using high-frequency induction welding for strong joints.
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