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Help CenterSteel Pipe & Tube & Galvanized Steel Pipe，GB/T 3091‑2024、GB/T 13793、GB/T 21835
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Steel Pipe & Tube & Galvanized Steel Pipe，GB/T 3091‑2024、GB/T 13793、GB/T 21835NegotiableMOQ: 5 Metric Tons -
Steel Pipe & Tube & Galvanized Steel Pipe，GB/T 3091‑2024、GB/T 13793、GB/T 21835NegotiableMOQ: 5 Metric Tons
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Steel Pipe & Tube & Galvanized Steel Pipe，GB/T 3091‑2024、GB/T 13793、GB/T 21835NegotiableMOQ: 5 Metric Tons
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Steel Pipe & Tube & Galvanized Steel Pipe，GB/T 3091‑2024、GB/T 13793、GB/T 21835NegotiableMOQ: 5 Metric Tons
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Steel Pipe & Tube & Galvanized Steel Pipe，GB/T 3091‑2024、GB/T 13793、GB/T 21835NegotiableMOQ: 5 Metric Tons
Galvanized Steel Pipe - Product Description
1. Product Definition & Classification
Galvanized steel pipe refers to carbon steel pipe coated with a zinc layer on the surface. It adopts the sacrificial anode protection principle to isolate air and moisture, effectively preventing the base metal from rusting and extending service life.
Classification by Galvanizing Process
Hot-dip Galvanized Pipe: The pipe is immersed in molten zinc liquid at 450℃±5℃. Zinc layer thickness ranges from 80–120μm with strong adhesion. It features long service life (30–50 years for outdoor use) and is widely applied in engineering projects.
Electro-galvanized Pipe: Produced by electroplating. The zinc layer is only 10–30μm with poor anti-corrosion performance. It is merely suitable for temporary use in dry indoor environments and prohibited for water supply systems.
Classification by Wall Thickness
Standard Pipe: Applicable for conventional pressure (≤1.6MPa) water supply, drainage and gas delivery.
Extra-heavy Pipe: Designed for high pressure and heavy load occasions with larger wall thickness and unit weight.
Classification by Pipe End
Threaded end: For threaded connection, mainly used for small-diameter pipes.
Plain end: For welding or flange connection, mainly used for large-diameter pipes.
2. Executive Standards
GB/T 3091-2024: Welded steel pipes for low-pressure fluid transportation
GB/T 13793: Straight seam electric resistance welded steel pipes
GB/T 21835: Dimensions and theoretical weights of welded steel pipes
3. Main Specifications (In accordance with GB/T 3091)
| Nominal Diameter | Inch Size | Outer Diameter (mm) | Standard Wall Thickness (mm) | Extra-heavy Wall Thickness (mm) | Weight of Standard Pipe (kg/m) | Weight of Extra-heavy Pipe (kg/m) |
|---|---|---|---|---|---|---|
| DN15 | 1/2" | 21.3 | 2.8 | 3.2 | 1.26 | 1.43 |
| DN20 | 3/4" | 26.9 | 2.8 | 3.2 | 1.63 | 1.85 |
| DN25 | 1" | 33.7 | 3.2 | 4.0 | 2.42 | 2.91 |
| DN32 | 1¼" | 42.4 | 3.5 | 4.0 | 3.14 | 3.58 |
| DN40 | 1½" | 48.3 | 3.5 | 4.0 | 3.58 | 4.10 |
| DN50 | 2" | 60.3 | 3.8 | 4.5 | 4.61 | 5.44 |
| DN65 | 2½" | 76.1 | 4.0 | 4.5 | 5.90 | 6.64 |
| DN80 | 3" | 88.9 | 4.0 | 4.75 | 6.78 | 7.77 |
| DN100 | 4" | 114.3 | 4.0 | 5.0 | 8.21 | 10.20 |
Standard Length: 6 meters per piece; customized length from 3m to 12m is available.
Pressure Rating: Standard pipe ≤1.6MPa; Extra-heavy pipe ≤2.5MPa.
4. Material & Production Process
Base Material
Mainly Q235B, Q345B carbon steel. Yield strength ≥235MPa, tensile strength: 375–500MPa.
Hot-dip Galvanizing Process
Degreasing → Pickling (oxide removal) → Flux treatment → Drying → Hot-dip galvanizing (450℃±5℃, 1–2 minutes) → Cooling → Passivation → Inspection → Packaging
Zinc Layer Requirements
Zinc layer thickness of hot-dip galvanized pipe ≥80μm. Uniform surface without missing plating or peeling.
5. Product Features
Excellent Anti-corrosion Performance: The zinc layer isolates corrosive substances. Zinc will corrode preferentially to protect the steel substrate even if the surface is scratched. Service life reaches 30–50 years in rural areas and 15–30 years in industrial or coastal areas.
High Mechanical Strength: Retain high compression, bending and impact resistance of steel pipes, applicable for structural support.
Easy Construction: Support cutting, welding, threaded connection and flange connection. Smooth surface for easy installation and maintenance.
Cost-effective & Eco-friendly: Although the initial cost is 20%–30% higher than black steel pipe, it requires no maintenance and has a long service life, leading to lower overall cost. The product is 100% recyclable.
6. Application Fields
Building water supply & drainage, fire protection sprinkler and hydrant systems.
Municipal engineering: Water pipeline, gas pipeline, cable conduit and tunnel support.
Industrial pipeline: Delivery of low-pressure fluid such as water, oil and air, anti-corrosion pipelines.
Steel structure: Curtain wall keel, brackets, scaffolding and guardrails.
7. Quality Inspection & Packaging
Inspection Items
Appearance: Smooth surface, free of cracks, missing plating and excessive zinc nodules.
Dimension Check: Outer diameter, wall thickness and length comply with national standards.
Zinc Layer Test: Thickness ≥80μm; no peeling after adhesion test.
Hydrostatic Test: No leakage after holding pressure for 5 seconds (2.0MPa for standard pipes, 2.5MPa for extra-heavy pipes).
Packaging
Standard length 6m per piece. Both ends are fitted with plastic caps. Bundled in sets (50 pieces per bundle). Marked with specification, execution standard, batch number and manufacturer.
8. Selection & Usage Tips
Choose hot-dip galvanized pipe exclusively. Electro-galvanized pipe is forbidden for water supply, fire protection and municipal projects due to poor anti-corrosion ability.
Verify the product complies with GB/T 3091 and check specifications including diameter, wall thickness and length as required.
Inspect zinc layer quality: uniform and bright surface without missing plating or peeling. Use thickness gauge to confirm the zinc layer is over 80μm.
Connection suggestion: Threaded connection for pipes below DN50; welding or flange connection for large-diameter pipes to ensure tight sealing.
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