| Tolerance | ±1% |
| Surface Treatment | galvanized |
| Standard | ASTM, GB, BS, EN, DIN |
| Alloy Or Not | Non-Alloy |
| Section Shape | Square, Rectangular can be customized |
| Out diameter ： | 30*30mm-200*400mm, can be customized |
| Length | 1-12m, can be customized |
| Thickness | 1.5mm-12mm, can be customized |
| Model number | 30*30mm-200*400mm, can be customized |
| Application | Structure Pipe, Construction, Steel structure engineering, Curtain wall construction etc. |
Product overview
Galvanized rectangular tubes are hollow long strips of steel with a rectangular cross-section. They belong to cold-formed hollow steel sections. They are made from strip steel and are processed through unpacking, flattening, coiling, welding into round tubes, which are then rolled into square rectangles. The surface zinc coating can form an oxide protective layer, and they are widely used as pipelines for transporting fluids.
Material & Chemical compostion
The material of galvanized rectangular pipes can be mainly classified into two categories: plain carbon steel and low alloy steel. Common grades of plain carbon steel include Q195, Q215, Q235 (such as Q235A, Q235B), SS400, 20# steel, 45# steel, etc.; common grades of low alloy steel include Q345 (such as Q345A, Q345B, Q345C, Q345D, Q345E), 16Mn, Q390, ST52-3, etc. Among them, Q235 and Q345 are the most widely used materials.
Dimensional Range & Tolerances
The dimensional tolerance follows the GB/T309-201 standard. The allowable deviation of the side length is from ±0.5mm to ±2.0mm. The thickness deviation is controlled within ±10%, the bending degree per square meter does not exceed 1.5mm, and the diagonal difference of the square and rectangular tubes should be less than 1.5% of the side length.
Rigorous Manufacturing Process
Our galvanized rectangular tubes go through 6 key steps to guarantee quality:
Raw Material Selection: We use high-quality low-carbon steel coils (Q235/Q355 grade) with stable chemical composition, ensuring base tube strength.
Forming & Welding: Steel coils are cold-formed into rectangular shapes via precision rollers, then welded using high-frequency induction welding (HFIW) for tight, smooth joints.
Deburring & Trimming: Welded tubes are deburred internally and externally, then cut to standard or custom lengths (max 12 meters) with laser precision.
Hot-Dip Galvanizing: Tubes are immersed in a 450℃ zinc bath, forming a 80-120μm thick zinc coating-this step ensures excellent corrosion resistance.
Cooling & Passivation: Galvanized tubes are cooled rapidly, then treated with a passivation solution to enhance zinc coating adhesion and prevent white rust.
Quality Inspection: Each tube undergoes dimensional checks, zinc coating thickness tests, and pressure tests (for leak resistance) before packaging.
3.Quality Inspection Stage
All our products undergo rigorous inspection processes and come with reliable quality assurance.
-Geometry-Inspection
English Caption: Check the side length, wall thickness, and diagonal tolerance of galvanized rectangular pipes with professional measuring tools to ensure compliance with international standards.
-Coating Thk Test
English Caption: Use a magnetic thickness gauge to detect the galvanized layer thickness of pipes, ensuring uniform coverage and excellent corrosion resistance.
-Hydrostatic Testing
English Caption: Conduct water pressure tests on pipes to verify pressure resistance and sealing performance, guaranteeing safe application in fluid transportation scenarios.
3. Product Highlights of Galvanized Rectangular Tubes
Our galvanized rectangular tubes excel in performance and versatility:
Corrosion Resistance: The hot-dip zinc coating protects against rust and oxidation, making them suitable for outdoor (e.g., building facades, fences) and humid environments (e.g., agricultural greenhouses).
Structural Strength: With wall thickness ranging from 1.2mm to 6mm and side sizes from 20×40mm to 200×300mm, they offer strong load-bearing capacity for structural frameworks.
Easy Installation: Smooth surfaces and precise dimensions allow quick assembly with bolts or welding, reducing on-site construction time.
Long Lifespan: Under normal use, the tubes have a service life of 15-20 years, minimizing maintenance and replacement costs for clients.
Why Choose Us for Galvanized Square Pipes?
We are a leading factory specializing in galvanized rectangular tubes, with over 10 years of experience in steel product manufacturing. Our 50,000-square-meter production base is equipped with 8 advanced production lines, enabling an annual output of 80,000 tons-capable of meeting large-volume orders from global clients (e.g., construction firms, hardware distributors). We hold ISO 9001 quality certification and comply with ASTM, EN, and GB standards, ensuring every batch of products meets strict quality requirements. As a direct manufacturer, we cut out middlemen, offering competitive factory-direct prices while providing customizable solutions (e.g., specific sizes, thicknesses) to fit unique project needs.
Quality is our top priority. Every galvanized square pipe undergoes strict inspection, from raw material selection to hot-dip galvanizing finish, meeting international standards for corrosion resistance, structural strength and durability. What you see is what you get-consistent dimensions, smooth surfaces and reliable performance for construction, scaffolding and industrial applications.
Packing and delivery
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