Galvanized square tube is a hollow square section steel pipe with a square cross-sectional shape and size, which is made by cold bending processing of hot-rolled or cold-rolled galvanized strip steel or galvanized coil as raw material, and then high-frequency welding. Alternatively, it is made by hot-dip galvanizing processing of pre-made cold-bent hollow section steel pipes into galvanized square and rectangular tubes.
Classification of Galvanized Square Tubes
Galvanized square tubes are divided into hot-dip galvanized square tubes and cold-dip galvanized square tubes based on their production processes. It is precisely because of the different processing methods of these two types of galvanized square tubes that they possess many distinct physical and chemical properties. In general, they have many differences in terms of strength, toughness, and mechanical properties.
Hot-dip Galvanized Square Tubes
Hot-dip galvanized square tubes are made by welding steel plates or steel strips into square tubes after bending and forming. These square tubes are then placed in a hot-dip galvanizing bath, where they undergo a series of chemical reactions to form another type of square tube. The production process for hot-dip galvanized square tubes is relatively simple and has high production efficiency, with a wide variety of specifications. The equipment and capital required for this type of tube are minimal, making it suitable for production by small galvanized square tube manufacturers. However, in terms of strength, this type of steel tube is significantly lower than that of seamless square tubes.
Cold-dip Galvanized Square Tubes
Cold-dip galvanized square tubes, on the other hand, use the principle of cold-dip galvanizing to give the square tubes anti-corrosion properties. Unlike hot-dip galvanizing, the cold-dip coating primarily prevents corrosion through electrochemical principles. Therefore, it is essential to ensure that the zinc powder makes sufficient contact with the steel to create an electrode potential difference, making the surface treatment of the steel very important.
Differences Between Hot-dip and Cold-dip Galvanized Square Tubes
Galvanized square tubes are categorized into hot-dip galvanized square tubes and electro-galvanized square tubes. Hot-dip galvanized square tubes include wet, dry, lead-zinc, and redox methods. The main differences between these hot-dip galvanizing methods lie in the activation of the tube surface after acid pickling of the steel pipes to improve the quality of the galvanizing. In current production, the dry method and the redox method are mainly used, with their characteristics shown in the table. Electro-galvanized zinc layers have a very smooth and dense surface, uniform structure, good mechanical properties, and corrosion resistance; zinc consumption is 60% to 75% lower than that of hot-dip galvanizing. Electro-galvanizing has a certain degree of technical complexity, but it is necessary for single-sided coating, double-sided coating with different thicknesses on the inner and outer surfaces, and galvanizing of thin-walled pipes.
Application of Galvanized Square Tubes
Due to the galvanizing process applied to square tubes, galvanized square tubes have greatly expanded their application range compared to regular square tubes. They are mainly used in curtain walls, construction, mechanical manufacturing, steel construction projects, shipbuilding, solar power steel structure projects, electrical projects, power plants, agriculture, and chemical machinery, glass curtain walls, automobile chassis, airports, and more.
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Square tube Specifications
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16×16×0.4～1.5
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380×380×8.0～14.0
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18×18×0.4～1.5
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400×400×8.0～14.0
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20×20×0.4～1.5
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420×420×10.0～14.0
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25×25×0.6～2.0
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450×450×10.0～14.0
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30×30×0.6～4.0
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480×480×10.0～14.0
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34×34×1.0～2.0
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500×500×10.0～14.0
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35×35×1.0～4.0
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38×38×1.0～4.0
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550×550×10.0～40.0
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40×40×1.0～4.5
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600×600×10.0～40.0
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44×44×1.0～4.5
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700×700×10.0～40.0
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45×45×1.0～5.0
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800×800×10.0～50.0
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50×50×1.0～5.0
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900×900×10.0～50.0
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60×60×1.5～5.0
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1000×1000×10.0～50.0
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70×70×2.0～6.0
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75×75×2.0～6.0
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80×80×2.0～6.0
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85×85×2.0～6.0
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95×95×2.0～8.0
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100×100×2.0～8.0
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120×120×4.0～8.0
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150×150×6.0～10.0
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180×180×6.0～12.0
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200×200×6.0～12.0
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220×220×6.0～14.0
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250×250×6.0～14.0
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280×280×6.0～14.0
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300×300×8.0～14.0
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320×320×8.0～14.0
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350×350×8.0～14.0
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Strict Quality Control:
1) During and after production, 4 QC staffs with more than 5 years experience inspect products in random.
2) National accredited laboratory with CNAS certificates
3) Acceptable inspection from third party appointed/paid by buyer, such as SGS, BV.
4) Approved by Malaysia, Indonesia, Singapore, Philippines, Australia, Peru and UK. We own UL /FM, ISO9001/18001, FPC certificates
Packing and Delivery:
Packing Details : in hexagonal seaworthy bundles packed by steel strips, With two nylon slings for each bundles.
Delivery Details : Depending on the QTY, normally one month.
