Contact Platform Support
Help CenterSteel Pipe & Tube & HDG Galvanized Steel Pipe，ASTM A53 Gr.A/B、EN 10255、BS1387、JIS G3452、ISO65
Related Products
-
Steel Pipe & Tube & Alloy Steel Pipe，P5/P9/P11/P22/P91、T11/T22/T91NegotiableMOQ: 5 Metric Tons -
Steel Pipe & Tube & High Pressure Boiler Tube，20G / 20MnG、15CrMoG / 12CrMoVG、P11/P22 / T11/T22、P91/T91、P92/T92NegotiableMOQ: 5 Metric Tons
-
Steel Pipe & Tube & Precision Steel Tube，20#、45#、Q345B、16Mn、40Cr、42CrMo、20CrMoNegotiableMOQ: 5 Metric Tons
-
Steel Pipe & Tube & Cast Tube，QT420-10、QT450-12，GB/T13295、ISO2531、HT200、HT250、ZG40Cr25Ni20（2520/HK40）、ZG3Cr24Ni7SiN、ZG40Ni35Cr26Si2NegotiableMOQ: 5 Metric Tons
-
Steel Coil & Strip & Hot Rolled Coil HRC，EN10025、ASTM A36、A572、JIS G3101 / G3131NegotiableMOQ: 5 Metric Tons
1. Product Overview
Hot-dip galvanized steel pipe (HDG GI pipe) takes low-carbon straight seam welded pipe or seamless steel pipe as substrate and is processed by complete internal and external hot-dip galvanizing for anti-corrosion. Different from outdated cold galvanized (electro-galvanized) pipe, it achieves long-lasting anti-corrosion effect through zinc-iron alloy composite coating. As standard general pipe for low-pressure fluid transportation and steel structure engineering, it is widely applied in domestic and overseas construction, municipal works, fire protection, agriculture and industrial projects.
Product Classification
(1) Classified by Forming Technology
High-frequency straight seam galvanized welded pipe (mainstream type): Cost-effective with full range of specifications, widely used for water supply & drainage, fire fighting and greenhouses.
Galvanized seamless steel pipe: Seamless structure with higher pressure resistance, suitable for high-pressure fluid delivery, chemical industry and heavy machinery.
(2) Classified by Galvanizing Technology
Hot-dip galvanizing (recommended): Thick coating with strong adhesion, service life up to 30-50 years, designated material for national standard engineering projects.
Cold galvanizing (electro-galvanizing): Thin coating easy to peel off, only for temporary light structures, forbidden in municipal and fire protection projects.
2. Applicable Standards
Domestic Standards
GB/T 3091-2025 Welded Steel Pipes for Low-pressure Fluid Service (implemented in March 2026, mandatory standard for fire protection and water supply)
GB/T 13912-2020 Metallic Coatings - Technical Requirements and Test Methods for Hot-dip Galvanized Coatings on Iron and Steel Articles
GB/T 13793 Straight Seam Electric Resistance Welded Steel Pipes
International Export Standards
ASTM A53 Gr.A/B, EN 10255, BS1387, JIS G3452, ISO65. We can provide corresponding material certificates, inspection reports and complete export inspection documents.
3. Base Material & Mechanical Properties
Common Steel Grades
Q235B (main grade), Q195, Q355B (high-strength thickened grade), equivalent to S235JR and ASTM A53 Gr.B internationally.
Core Mechanical Parameters
Yield strength: ≥235MPa (Q235B); ≥355MPa (Q355B)
Tensile strength: 370–500MPa
Elongation: ≥21%, excellent bending and welding performance
Hydrostatic test: DN15-DN165 bears 3.0MPa; DN200-DN300 bears 5.0MPa, no leakage after pressure holding.
4. Production Process Flow
Steel pipe substrate → Degreasing & oil removal → Pickling & rust removal → Water washing & flux coating → Drying & preheating → Hot-dip galvanizing in molten zinc at 450-500℃ → Internal & external zinc trimming and leveling → Water cooling & passivation → Cleaning & drying → Marking → Inspection & packaging → Warehousing & delivery
Key Galvanized Coating Parameters (National Standard)
Double-sided zinc coating weight: Standard type ≥300g/㎡; heavy anti-corrosion type ≥500g/㎡
Coating thickness: 30–100μm, forming double protective layers: outer pure zinc layer + inner zinc-iron alloy layer
Coating inspection: No red rust after at least 5 times copper sulfate immersion test; no peeling or missing coating after impact and bending adhesion tests.
5. Complete Specification Parameters
Nominal Diameter Range
DN15(1/2") ~ DN300(12"), outer diameter: 21.3mm~323.9mm
Wall Thickness Series
Standard wall thickness and thickened wall thickness, thickness range 2.0mm–10.0mm, customized non-standard wall thickness available.
Standard Fixed Length
6 meters (universal national standard length); customized lengths of 5.8m, 9m, 12m and special cut lengths are acceptable.
Pipe End Treatments
Four options: plain end, threaded end (with coupling), beveled end and flanged end.
Weight Conversion Formula
Theoretical weight of galvanized pipe = weight of black pipe × galvanizing weight gain coefficient (coefficient ranges 1.064~1.028 for wall thickness 2.0~4.5mm)
6. Core Product Advantages
Outstanding anti-corrosion performance & long service lifeThe zinc layer provides sacrificial anode protection. When the coating is scratched, zinc rusts first to protect steel substrate. The service life exceeds 50 years in rural atmospheric environment and over 30 years in buried soil and humid outdoor conditions, greatly reducing later maintenance cost.
Smooth inner wall with low fluid resistanceNo rust burrs inside after galvanization, low water/gas transmission loss, less scaling and blockage, ideal for long-term delivery of fire sprinkler water and tap water.
Easy construction with multiple connection methodsSupports threaded connection, flange connection, welding and grooved clamp connection. Complete matching pipe fittings improve on-site installation efficiency.
Safe, eco-friendly and recyclableNon-toxic zinc layer complies with drinking water pipeline hygiene standards. Discarded pipes can be 100% recycled without heavy metal pollution.
Lower comprehensive cost in full life cycleAlthough the initial purchase cost is higher than black pipes, painting and anti-corrosion maintenance are unnecessary, cutting total life-cycle cost by over 40%.
7. Main Application Fields
Fire protection engineering (core application)Fire hydrant main pipes, automatic sprinkler pipe networks, water supply pipes for fire pump houses, meeting national fire acceptance standards with stable pressure resistance and no pipe burst risk.
Building water supply and drainageCold & hot water pipelines, rainwater and sewage pipes for residences, shopping malls and factories; heating, ventilation and compressed air pipelines.
Municipal gas infrastructureUrban medium & low-pressure natural gas and coal gas transmission pipelines; road guardrails, street lamp supports and bridge steel structures.
Agricultural facilitiesGreenhouse frames, breeding shed supports and farmland irrigation pipes, resistant to high humidity, wind and snow corrosion.
Industrial fluid transportationDelivery of clean water, engine oil, sewage and low-pressure air; cable protection sleeves and equipment supports.
Temporary structuresConstruction scaffolding, protective fences and steel structural supports.
8. Packaging, Storage & Delivery Instructions
Packaging Method
Small-diameter pipes DN15-DN100 bundled with steel strips in fixed quantity per bundle; large-diameter pipes packed separately with plastic end caps to avoid collision damage and foreign matter entering.
Storage Requirements
Store in dry and ventilated warehouses, avoid long-term outdoor rain exposure; do not stack with acid, alkali and corrosive materials. Handle gently during loading and unloading to prevent impact scratches on zinc coating.
Delivery Information
Sufficient factory stock, delivered from Tianjin Port with production and shipment cycle of 5-7 days. Full container export supported; full set of foreign trade documents including packing list, certificate of origin, material certificate and commodity inspection report can be provided.
9. Quality Assurance & Acceptance Standards
Every batch of pipes undergoes full hydrostatic test, random zinc coating inspection and full appearance inspection.
Appearance standard: Uniform bright silver-gray surface, no missing galvanization, black spots, burrs or zinc tumors; smooth welds without cracks.
Third-party test reports (zinc coating thickness, mechanical property, hydrostatic pressure, salt spray test) are available, supporting customer on-site inspection.
Quality warranty: Under standardized normal use, the zinc layer will not peel off or suffer large-area corrosion within 5 years excluding man-made damage.
Send Inquiry to This Supplier
You May Also Like
-
Steel Coil & Strip & Cold Rolled Steel Coil，HC220YD、HC260YD、HC300LA、HC340LA、HC420LANegotiableMOQ: 5 Metric Tons
-
Steel Coil & Strip & Prepainted Steel Coil，DX51D+Z、DX52D+Z、DX53D+Z、DX51D+AZ、DX52D+AZ、DX53D+AZ、SPCC、SPCD、DC01NegotiableMOQ: 5 Metric Tons
-
Steel Sheet & Plate & Pressure Vessel Plate，Q245R、Q345R、Q370R、Q420R、Q460R、16MnDR（-40℃）、09MnNiDR（-70℃）、15CrMoR、14Cr1MoR、12Cr1MoVRNegotiableMOQ: 5 Metric Tons
-
Steel Sheet & Plate & Checkered Plate，BCP270、BCP340、BCP400、1060、3003、5052、5083NegotiableMOQ: 5 Metric Tons
-
Steel Sheet & Plate & Shipbuilding Steel Plate，A、B、D、E（CCS A/CCS B/CCS D/CCS E）、AH32、DH32、EH32、AH36、DH36、EH36NegotiableMOQ: 5 Metric Tons
-
Steel Sheet & Plate & Boiler Steel Plate，Q245R、Q345R、15CrMoR、12Cr1MoVR、P265GH、16Mo3、13CrMo44、SA516 Gr60/70、SA387 Gr12/Gr22NegotiableMOQ: 5 Metric Tons
-
Steel Sheet & Plate & Steel Sheet Pile，Q235B、Q355B/SY295/SY390、S275JR、S355GP、S430GP、A328 Gr50、A572 Gr50、A690NegotiableMOQ: 5 Metric Tons
-
Steel Rebar & Deformed Steel Bar，Φ12/14/16/18/20/22/25/28/32mmNegotiableMOQ: 5 Metric Tons
-
Steel Wire & Electro Galvanized Wire，Q195、Q235、Q235B、SWC、SWP-BNegotiableMOQ: 5 Metric Tons
-
Flat Steel & Flat Steel Bar，20×3、25×4、30×4、40×4、40×5、50×5、50×6、60×6、80×8、100×10NegotiableMOQ: 5 Metric Tons
