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What is a GI pipe?
sourceJUNNAN NEWS
publisherGloria
time2026/04/27
- GI pipe (galvanized iron pipe), is a type of metal pipe coated with zinc (a zinc layer) on the surface of ordinary steel pipe, primarily to prevent rust and extend its service life. I
1. The Nature of Galvanized Steel Pipes
Galvanized steel pipe are metal pipes with a layer of zinc coated on the surface of ordinary steel pipes. This layer of zinc acts like a protective suit for the steel pipe, protecting it in two ways:
· Physical Barrier: The zinc layer isolates air and moisture, preventing the steel pipe from rusting.
· Chemical Protection: Even if the coating is damaged, the zinc reacts with oxygen first, protecting the steel pipe from corrosion.
2. Why Choose Galvanization
Coating steel pipes with zinc is not an arbitrary decision; there are solid reasons behind it:
Cost-effective: Compared to stainless steel pipes, it is 30-50% cheaper.
Extended Lifespan: Ordinary steel pipes rust in 3 years, while galvanized pipes can last more than 15 years.
Easy Construction: Retains the weldability of steel pipes while providing rust protection.
3. Applications of Galvanized Steel Pipes
Piping Systems: Galvanized pipe steel are widely used for water supply due to their corrosion resistance, such as urban water supply pipelines and fire protection systems.
Irrigation and Agriculture: They are ideal for water distribution in the agricultural sector, such as sprinkler systems and large-scale farm water supply pipelines.
Construction Applications: GI pipes provide a sturdy framework for construction projects, such as structural supports, greenhouse frames, and guardrails.
Industrial Uses: Galvanized pipe price reliably transport chemicals and gases, such as high-pressure fluids in the petroleum, chemical, and pharmaceutical industries.
Drilling Systems: Their strength makes them suitable for high-pressure drilling applications.
Industry Standards
US: ASTM A53 (hot-dip galvanized seamless and welded pipe)
Europe: EN 10240 (hot-dip galvanized pipe)
China: GB/T 3091-2015 (welded galvanized steel pipe)
Galvanizing treatment
Hot-dip galvanizing
Process flow: Degreasing (alkaline washing) → Pickling (rust removal) → Coating (ammonium zinc chloride) → Hot-dip galvanizing (450℃) → Cooling → Passivation
Zinc layer thickness:
Standard thickness: 65-85μm
Common range: 45-120μm
Galvanizing amount: 320-600g/m²
Advantages:
Thick zinc layer (70-100μm), strong corrosion resistance
Strong bonding of zinc-iron alloy layer
Gi electrical pipe
Process flow: Electrolytic degreasing → Pickling → Electro-Galvanizing (zinc salt solution + current) → Passivation
Zinc Layer Thickness:
Standard Thickness: 5-15μm
Galvanizing Weight: 30-100g/m²
Pipe Size
| Hot Dip Galvanized Round Steel Pipe | |||||
| Specification | Wall Thickness | Length | Specification | Wall Thickness | Length |
| 26.9 | 1.5-3.25MM | 1-12M | 32 | 1.8-4.0MM | 1-12M |
38 | 1.8-4.0MM | 1-12M | 33.7 | 1.8-4.25MM | 1-12M |
42.3 | 1.8-4.25MM | 1-12M | 48.3 | 1.8-4.75MM | 1-12M |
50 | 1.8-7.0MM | 1-12M | 51 | 1.8-7.0MM | 1-12M |
56 | 1.8-7.0MM | 1-12M | 57 | 1.8-7.0MM | 1-12M |
60.3 | 1.8-7.0MM | 1-12M | 76.1 | 2.5-7.0MM | 1-12M |
70 | 2.5-7.0MM | 1-12M | 72 | 2.5-7.0MM | 1-12M |
73 | 2.5-7.0MM | 1-12M | 83 | 2.5-7.0MM | 1-12M |
| 95 | 2.5-7.0MM | 1-12M | 88.9 | 2.5-9.5MM | 1-12M |
102 | 2.2-9.5MM | 1-12M | 108 | 2.3-11.75MM | 1-12M |
114.3 | 2.5-11.75MM | 1-12M | 121 | 2.5-11MM | 1-12M |
127 | 2.5-11MM | 1-12M | 133 | 2.5-9.75MM | 1-12M |
139.7 | 2.5-10MM | 1-12M | 146 | 2.5-10MM | 1-12M |
152 | 2.5-10MM | 1-12M | 159 | 2.5-11.75MM | 1-12M |
166 | 2.5-10MM | 1-12M | 168.3 | 2.75-11.75MM | 1-12M |
177.8 | 2.75-11.75MM | 1-12M | 180 | 2.75-11.75MM | 1-12M |
194 | 2.75-11.75MM | 1-12M | 203 | 2.75-11.75MM | 1-12M |
190.7 | 2.75-12MM | 1-12M | 216.3 | 2.75-12MM | 1-12M |
267 | 2.75-12MM | 1-12M | 219 | 2.75-12MM | 1-12M |
244.5 | 4-12MM | 1-12M | 273.1 | 5-12MM | 1-12M |