Contact Platform Support
Help CenterSteel Pipe & Tube & Hot-dip Galvanized Steel Pipe，ASTM A53、ASTM A123、BS1387、EN10255、JIS G3442、ISO65
Related Products
-
Steel Pipe & Tube & Alloy Steel Pipe，15CrMoG、12Cr1MoVG、P12、P22、P91、P92、16MnDG、30CrMo、42CrMoNegotiableMOQ: 5 Metric Tons -
Steel Pipe & Tube & Oil Country Tubular Goods，E75、X95、G105、S135、V150NegotiableMOQ: 5 Metric Tons
-
Steel Pipe & Tube & Cast Steel Pipe， ASTM A216 WCB、A217 C12、GX5CrNi25-21、JIS G5122 SCHNegotiableMOQ: 5 Metric Tons
-
Steel Pipe & Tube & Precision Steel Pipe，DIN 2391、EN 10305-1、ASTM A519、ASTM A269、JIS G3445NegotiableMOQ: 5 Metric Tons
-
Steel Coil & Strip & Hot Rolled Coil，ASTM A36、ASTM A572 Gr50、EN10025、JIS G3101、JIS G3131、API 5LNegotiableMOQ: 5 Metric Tons
1. Product Overview
Hot-dip Galvanized Steel Pipe (HDG Pipe / GI Pipe) is manufactured based on low-carbon straight seam welded pipes or seamless steel pipes via full internal and external hot-dip galvanizing process. Different from electro-galvanized (cold galvanized) pipes, it features thick zinc coating and strong adhesion with long-term rust resistance, serving as the mainstream pipe widely used in low-pressure fluid transportation, steel structure and fire protection projects.
Process Principle
After degreasing, pickling, flux coating and drying, steel pipes are immersed in molten zinc liquid at 450–500°C. Metallurgical reaction occurs between the pipe wall and zinc to form a composite protective layer consisting of zinc-iron alloy layer and pure zinc surface layer. It provides dual anti-corrosion protection including physical isolation and sacrificial anode protection of electrochemistry. When the coating is damaged, zinc will corrode preferentially to protect the steel substrate from rusting.
2. Base Material & Mechanical Properties
Common Steel GradesQ195, Q235B (Main Grade), Q355B; equivalent international grades: A53 Gr.A/B, S235JR, STK400
Mechanical Indicators (GB/T 3091-2015)
Yield Strength: ≥235MPa
Tensile Strength: ≥370MPa
Elongation after Fracture: ≥25%
Bend Test: Pipes DN≤50 shall have no cracks or zinc coating peeling after 90° bending
Hydrostatic Test: Each pipe is tested under water pressure; standard working pressure ≤2.5MPa, thickened pipes support higher pressure grades
3. Implementation Standards
Domestic Standards
GB/T 3091-2015 Welded Steel Pipes for Low-Pressure Fluid DeliveryGB/T 13912 Metallic Coatings — Hot-Dip Galvanized Coatings on Ferrous Articles — Technical Requirements and Test Methods
International Export Standards
ASTM A53, ASTM A123, BS1387, EN10255, JIS G3442, ISO65
4. Complete Specification Parameters
Nominal Diameter: DN15 (1/2") ~ DN300 (12"), customized large diameter DN350~DN500 available
Wall Thickness Grades
Standard Wall SCH40: 1.8mm–8.0mm
Extra Thick Wall SCH80: 3.0mm–10mm for higher pressure resistance
Standard Length: 6 meters fixed length; non-standard length 3m/9m/12m customizable
Pipe End Treatment
Plain End: For steel structure supports and welding connection
Threaded End with Matching Couplings: For water supply, drainage and fire protection threaded installation
Beveled End: For large-diameter welding projects
5. Quality Standards for Zinc Coating
Zinc Coating Thickness: Standard ≥65μm; customized heavy zinc coating ≥85μm
Zinc Coating Weight: Average ≥500g/㎡, no single sample lower than 480g/㎡
Test Requirements
Copper Sulfate Immersion Test: No red rust after 5 consecutive immersions
Neutral Salt Spray Test: Minimum 240 hours without red rust for standard grade, up to 1000 hours for heavy zinc coating grade
Appearance Requirements: Uniform silvery bright surface without missing galvanization, zinc tumors, peeling, scratches or black spots; complete internal and external galvanization without blind areas
6. Core Product Advantages
Superior Corrosion Resistance & Long Service LifeSuitable for outdoor open-air, underground burial, humid and saline-alkali environments with service life of 20–50 years. Its anti-corrosion performance is over 3 times that of electro-galvanized pipes, greatly reducing later maintenance costs.
Extraordinary Coating AdhesionMetallurgical bonding of zinc-iron alloy ensures the zinc coating will not peel off in large pieces after cutting, threading, bending and welding.
Excellent MachinabilitySupports cutting, threading, tapping, welding, punching and bending; multiple installation methods available including threaded connection, flange connection and welding.
Smooth Fluid TransportationSmooth internal galvanized wall reduces adhesion of limescale and impurities, lowering flow resistance for water and gas delivery and preventing clogging.
High Comprehensive Cost PerformanceOne-step galvanizing forming without on-site anti-rust painting, with lower overall project cost than stainless steel and plastic-lined anti-corrosion pipes.
Wide Application AdaptabilityStable performance for indoor, outdoor, buried, coastal high salt fog and greenhouse humid environments.
7. Main Application Fields
Fire Protection Engineering: Fire sprinkler and fire hydrant water supply pipelines (national standard mandates hot-dip galvanizing)
Municipal Fluid Transportation: Low-pressure pipelines for tap water, gas and sewage
Electric Power & Communication: Cable protection sleeves and substation supports
Agricultural Facilities: Greenhouse frames and farmland irrigation pipelines
Steel Structure Engineering: Factory frames, guardrails, fences, photovoltaic supports and scaffolding
Industrial Equipment: HVAC pipelines, cooling circulation pipelines and equipment support frames
Infrastructure & Bridge: Pipe piles for trestles, road guardrails and foundation pit supports
8. Complete Production Process
Incoming inspection of black steel pipes → Degreasing & Oil Removal → Clean Water Rinsing → Hydrochloric Acid Pickling for Oxide Scale Removal → Neutralization Cleaning → Flux Coating Soaking → Drying → Hot-Dip Galvanizing at 500°C → Internal & External Zinc Blowing & Cleaning → Water Cooling & Passivation → Finished Product Inspection → Spraying Marking & Coding → Bundling & Warehousing
9. Packaging, Shipment & Lead Time
Packaging: Bundled with steel strips, plastic end caps for pipe end protection; export orders wrapped with blue waterproof woven cloth for moisture and rust prevention
Lead Time: 5–7 days for regular stock products; 7–12 days for customized pipes with special wall thickness or length
Minimum Order Quantity: 10 tons; free samples of 20cm length available for testing
Send Inquiry to This Supplier
You May Also Like
-
Steel Coil & Strip & Cold Rolled Steel Coil，JIS G3141、EN 10130、ASTM A1008、DIN 1623NegotiableMOQ: 5 Metric Tons
-
Steel Coil & Strip & Prepainted Galvanized Coil，ASTM A755、EN 10169、JIS G3312、JIS G3322、ISO 9001NegotiableMOQ: 5 Metric Tons
-
Steel Sheet & Plate & Pressure Vessel Steel Plate，Q245R、Q345R、Q370R、Q420R、Q460R、Q690DR、16MnDR、09MnNiDR、06Ni9DRNegotiableMOQ: 5 Metric Tons
-
Steel Sheet & Plate & Shipbuilding Steel Plate，ASTM A131、EN 10025、JIS G3106NegotiableMOQ: 5 Metric Tons
-
Steel Sheet & Plate & Boiler Steel Plate，Q245R、Q345R、Q370R、Q420R、Q460R、15CrMoR、14Cr1MoR、12Cr1MoVRNegotiableMOQ: 5 Metric Tons
-
Steel Sheet & Plate & Steel Sheet Pile，Q235B、SS400、Q355B、Q355C、Q390B、S355GP、Q355NQR、ASTM A690、SMA500NegotiableMOQ: 5 Metric Tons
-
Steel Sheet & Plate & Checkered Steel Plate，Q235B、Q355B、Q355C、CCSA、CCSB、AH36、Q355NH、Q355NQRNegotiableMOQ: 5 Metric Tons
-
Steel Rebar & Hot Rolled Ribbed Bars，HRB400、HRB500、HRB600、HRB400E、HRB500E、HRB600E、HRBF400E、HRBF500ENegotiableMOQ: 5 Metric Tons
-
Steel Wire & High Tensile Strength Steel Wire，Q195、Q235、SWRCH6A、SWRCH8A、SWRCH10A、SWRCH22A、SWRCH35K、45#、SWRH62B、SWRH72B、SWRH77B、SWRH82BNegotiableMOQ: 5 Hectares
-
Flat Steel Bar & Flat Steel，Q235B、SS400、Q355B/Q355C/Q355D、S355JR、20#、35#、45#、65Mn、60Si2MnNegotiableMOQ: 5 Metric Tons
