
Galvanized square pipe is made from hot-rolled or cold-rolled steel strips, processed through welding or cold bending to form square-section pipes. A galvanized coating forms a corrosion-resistant layer, commonly available in cold-dip galvanizing and hot-dip galvanizing methods. The corrosion protection lifespan can reach 50 years. It possesses excellent mechanical properties and corrosion resistance, and is widely used in construction, machinery, transportation, and other fields.
Glory Steel supplies hot-dip Square GI pipes with zinc coatings ranging from Z30 to Z275. As a top-tier supplier in China, we can customize and produce square tubing in all sizes.
Specification
| Item | Galvanized Square Tubes |
| Country of Origin | Tianjin, China |
| Surface Treatment | Galvanized |
| Coating | Z30-Z275 |
| Cross-sectional Shape | Square, Rectangular |
| Material | Q195, Q215, Q235 (A/B), Q345 (B/C/D/E), S275/JR, S355JR, A53, st37, 10#-45#, etc. |
| Standards | GB, ASTM, JIS, BS, AISI, EN, DIN, API |
| Certifications | ISO9001, API, CE, JIS, GS, etc. |
| Length | 1-12m (6m/6.4m/12m) |
| Wall Thickness | 0.5-25mm |
| Production Process | ERW, Cold-rolled, Hot-rolled/Cold-rolled |
| Packaging | Standard Airworthiness |


Features
- Excellent Corrosion Resistance: The zinc layer formed on the surface through the galvanizing process provides rust and oxidation resistance, significantly extending service life. Service life can reach over 20 years in suburban, urban, and coastal areas.
- Good Mechanical Properties: The base material is carbon steel square tubing, which inherently possesses high strength and rigidity, impact resistance, and can withstand large loads. It can be used for structural support.
- Excellent Processing Performance: It can be welded, cut, and bent, making installation simple. It is suitable for everything from door and window frames to large steel structure projects, offering a variety of sizes and high construction efficiency.
- High Cost-Effectiveness: The galvanized layer has a smooth surface and uniform color, allowing for direct exposed use. It has low maintenance costs, a long service life, and overall cost-effectiveness.


Application areas
- Construction Engineering and Steel Structure Products: Columns, beams, and support pipes for steel structure buildings, stadiums, and bridges; pipe racks for plumbing systems, drainage pipes, and stair handrails; curtain wall frames; door and window fabrication; underground pipe support and wiring.
- Industrial Manufacturing and Supports: Manufacturing of agricultural and chemical machinery; materials for oil well drilling and pipelines in the oil and gas industry; photovoltaic supports; advertising racks, etc.
- Transportation and Municipal Engineering: Automobile frames and chassis; subway and highway guardrails; street light poles; pipes for charging stations.
- Furniture and Agriculture: After welding, it can be used as animal and field fences; table, chair, and shelf materials; water supply, drainage, and pipeline materials.


Production process
Hot-dip galvanized square tube
Hot-rolled/cold-rolled steel sheet/strip → Cold bending + high-frequency welding → Pickling and rust removal → Neutralization and cleaning → Drying → Hot-dip galvanizing (450-500℃ zinc bath) → External blowing for zinc removal/Internal blowing for slag removal → Water cooling and curing → Passivation treatment → Eddy current testing + hydrostatic testing → Finished product inspection → Packaging and warehousing.
Electro-galvanized (cold galvanizing) Square tube
Surface pretreatment → Electro-galvanizing (zinc salt solution electrolytic deposition) → Water washing → Drying → Finished product inspection → Packaging and warehousing.


Quality Inspection Process
- Raw Material: Verify steel grade, certificates, and surface quality.
- Production: Control forming dimensions, ensure sound welding, and maintain uniform zinc coating.
- Finished Product: Check dimensions, zinc layer thickness, pressure tightness, and surface finish.


Galvanized square pipe weight chart
| Outer side length (mm) | WT(mm) | Weight (kg/m) |
| 20×20 | 1.0 / 1.2 / 1.5 | 0.59 / 0.69 / 0.83 |
| 25×25 | 1.0 / 1.2 / 1.5 / 2.0 | 0.75 / 0.88 / 1.08 / 1.40 |
| 30×30 | 1.5 / 2.0 / 2.5 | 1.33 / 1.73 / 2.11 |
| 40×40 | 1.5 / 2.0 / 2.5 / 3.0 | 1.81 / 2.37 / 2.91 / 3.43 |
| 50×50 | 2.0 / 2.5 / 3.0 / 4.0 | 3.02 / 3.72 / 4.40 / 5.69 |
| 60×60 | 2.0 / 2.5 / 3.0 / 4.0 | 3.67 / 4.53 / 5.37 / 6.98 |
| 80×80 | 3.0 / 4.0 / 5.0 | 7.31 / 9.56 / 11.73 |
| 100×100 | 3.0 / 4.0 / 5.0 / 6.0 | 9.21 / 12.09 / 14.91 / 17.66 |
| 120×120 | 3.0 / 4.0 / 5.0 / 6.0 | 11.11 / 14.62 / 18.06 / 21.43 |
| 150×150 | 4.0 / 5.0 / 6.0 / 8.0 | 18.32 / 22.68 / 26.98 / 35.34 |


Theoretical weight formula
Weight per meter (kg/m) = 0.02466 × (side length + side length – wall thickness × 2) × wall thickness × (1.03~1.06).
Zinc Coating Comparison Table for Different Standards
| Standard | Commonly used levels | Zinc coating weight (g/m²) | Zinc layer thickness (μm) |
| ASTM A653 / A1011 | G60 | ≥180 | ≥45 |
| G90 | ≥275 | ≥67 | |
| G120 | ≥365 | ≥90 | |
| EN 10346 / EN 10219 | Z275 | ≥275 | ≥67 |
| Z350 | ≥350 | ≥85 | |
| Z450 | ≥450 | ≥110 | |
| GB/T 6728 / GB/T 2518 | DX51D+Z275 | ≥275 | ≥67 |
| DX51D+Z350 | ≥350 | ≥85 | |
| JIS G3302 | Z275 | ≥275 | ≥67 |
| AS/NZS 1365 | Z275 | ≥275 | ≥67 |


Why Choose Us?
- Automated Production: Full-process intelligent equipment coverage ensures short delivery cycles, high dimensional accuracy, and batch consistency.
- Flexible Customization: Supports non-standard specifications; samples of irregular cross-sections/special zinc coatings are available within 72 hours; customized solutions have been provided to over 200 industries.
- Guaranteed Quality: 12 inspection processes from raw materials to finished products ensure zinc coating uniformity is 1.5 times higher than national standards; products have passed EU CE certification.
- High Cost-Effectiveness: Professional export services, factory direct sales, no middlemen. Flexible minimum order quantities for trial orders; supports FOB/CIF/CFR/Ex-Works and other trade terms.

FAQs


Glory Steel Plant, located in Tianjin, China, is an ISO 9001, ISO 14001, and CE certified factory with an annual output of 100,000 tons. We specialize in producing galvanized pipes, stainless steel pipes, and alloy steel pipes. With our high-quality products and services, we export to over 120 countries.
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