Tianjin Brisk Steel is one of the manufacturers of Hot Dip Galvanized Steel Pipe / HDG Pipe / HDG Steel Pipe Galvanized Iron Pipe / Zinc Coated Steel Tube in China. Our products are mainly exported to the Middle East, Southeast Asia, Europe, New Zealand, and other regions.If you would like to learn more about our products, feel free to contact us and send your purchase list.
Brisk Steel Core Processes of Hot-Dip Galvanizing
Overall zinc immersion
- Cleaned carbon steel pipe is fully immersed in molten zinc at ~450°C.
- The entire bundle of steel pipes is fully immersed in the molten zinc bath, with the immersion time adjusted according to pipe diameter and wall thickness: 1–3 minutes for thin-walled pipes and 3–8 minutes for large, thick-walled pipes.
- This process triggers a metallurgical-chemical reaction between the steel pipes and the molten zinc, resulting in a metallic bond rather than a simple coating.
Controlled-Speed Withdrawal & Coating Thickness Control
- Coating thickness is controlled by the lifting speed: a slower lift results in a thinner coating, while a faster lift produces a thicker coating, meeting various anti-corrosion requirements ranging from 200 to 750 g/m².
Internal and External Blowing (Critical Step for Steel Pipes)
- Outer Surface: High-pressure air blasts remove excess zinc from the exterior, eliminating zinc nodules and lumps to ensure a smooth, aesthetically pleasing finish;
- Internal Bore: High-pressure steam or compressed air is blown through the pipe interior to remove excess zinc, preventing internal diameter reduction or blockages and ensuring unobstructed fluid flow.
ERW PROCESS
Mainstream international standards
Fluid Conveyance Piping (Water Supply & Drainage, Fire Protection, Gas)
- ASTM A53 Gr.A/Gr.B (Standard specification for low-pressure fluid piping)
- ASTM A795: Dedicated for fire sprinkler systems (UL/FM certified)
- EN 10255 (EU series: light, medium, and heavy wall thicknesses)
- BS 1387 (British Standard threaded galvanized pipe)
Structural / Scaffolding Piping
- EN 39: HDG steel pipe for scaffolding
- EN 10219 / ASTM A500: Cold-formed structural circular hollow sections
- JIS G3444: Galvanized pipe for structural applications
Coating Inspection Standards
- ASTM A123 / ISO 1461 (Inspection of hot-dip galvanized coating thickness and adhesion)
Why choose HDG Pipe of Brisk Steel
Dual anti-rust protection: Barrier protection + sacrificial anode protection. Even minor scratches/cut edges will not rust, zinc corrodes first to shield steel.
Ultra-long service life: 20–50 years outdoor service; 25–30 years urban atmosphere, 15–20 years coastal salt-spray environment.
Low maintenance cost: No repainting required for decades, ideal for outdoor infrastructure.
Full-size compatibility Support threading, grooving, welding, all standard pipe fittings match perfectly.
End Process
Support threading, grooving, plain end
Application of HDG Pipe
Municipal Engineering：Domestic water supply, fire sprinkler pipeline, natural gas low-pressure transport
Construction & Structure：Scaffolding, guardrail, fence, building steel frame
Agriculture：Farm irrigation pipeline, greenhouse support
Infrastructure：Highway guardrail, cable conduit, underground buried pipeline
Industrial Factory：Compressed air piping, outdoor equipment support
Frequently Asked Questions (FAQ)
Q: What's the difference between HDG pipe and pre-galvanized pipe?
A: HDG pipe is post-galvanized after pipe forming, thick zinc coating 200–750g/m², inner & outer full coating, suitable for outdoor & corrosive areas. Pre-galvanized is galvanized steel coil then rolled into pipe, thin zinc layer only for indoor dry use.
Q: Can hot dip galvanized steel pipe be welded?
A: Yes. Remove local zinc coating before welding, then touch-up anti-rust zinc paint on weld joint after welding to restore protection.
Q: What sizes can Brisk Steel supply?
A: OD range DN15 (1/2") ~ DN500 (20"), wall thickness SCH20–SCH80 / 1.5–10mm; standard length 6m/12m, customized length available.
Q: Is HDG pipe suitable for coastal salt water environment?
A: Yes, thick zinc layer provides reliable anti-salt-spray performance, service life 15–25 years under coastal climate.
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