01 / PRODUCT OVERVIEW & KEY PARAMETERS
| Item / Parameter | Specification |
| Product Name | Galvanized Steel Pipe (HDG & Pre-Galvanized GI Pipe) |
| Manufacturing Types | Hot Dip Galvanized (HDG), Pre-Galvanized (GI), Electro-Galvanized (EG) |
| Outer Diameter (OD) | 1/2" to 24" (21.3 mm – 610 mm) | Square: 20x20 – 400x400 mm |
| Wall Thickness (WT) | SCH 10 to SCH 80, Class A / B / C, Light / Medium / Heavy (1.0 mm – 15.0 mm) |
| Zinc Coating Mass | • Pre-Galvanized: 40 – 120 g/m² (5 – 17 μm)
• Hot-Dip Galvanized (HDG): 220 – 600 g/m² (35 – 85 μm) |
| Standard Specifications | ASTM A53 Gr. A/B, BS 1387, EN 10255, ASTM A795, JIS G3444, DIN 2440, AS 1074 |
| Length Options | 5.8m, 6.0m, 11.8m, 12.0m, or Precision Cut Lengths (1m - 12m) |
| End Preparation | Plain End (Square Cut), Threaded & Coupled (NPT / BSPT), Roll Grooved |
02 / TECHNICAL COMPARISON: HOT-DIP VS. PRE-GALVANIZED
| Feature / Parameter | Hot-Dip Galvanized (HDG Pipe) | Pre-Galvanized (GI Pipe) |
| Galvanizing Process | Formed black pipe immersed in 450°C molten zinc bath | Roll-formed from continuous galvanized steel strip |
| Zinc Layer Weight | 220 – 600 g/m² (35 – 85 μm) - Heavy Duty | 40 – 120 g/m² (5 – 17 μm) - Regular Duty |
| Corrosion Resistance | ⭐⭐⭐⭐⭐ (20 – 50+ Years outdoor / underground) | ⭐⭐⭐ (5 – 15 Years indoor / mild outdoor) |
| Welding Seam Protection | 100% full coverage inside and outside after welding | Zinc spraying repair on external seam |
| Typical Applications | Firefighting, water gas transmission, solar frames | Greenhouse frames, furniture, scaffolding, conduit |
03 / ENGINEERING ADVANTAGES & KEY FEATURES
| ?️ Extreme Corrosion Protection | ? Diverse End Processing Options |
| Thick metallurgical zinc-iron alloy layer provides dual sacrificial cathodic protection and physical barrier against severe weather, moisture, and chemical exposure. | Accurate CNC threading (BSPT / NPT) fitted with galvanized socket couplings, or precision roll grooving for ultra-fast, clamp-based fire protection piping installation. |
| ✨ Smooth Surface & Bright Spangle | ? 100% Pressure & Adhesion Tested |
| Smooth inner bore reduces fluid friction loss and scale buildup; bright regular spangle finish ensures premium commercial appearance. | Rigorous hydrostatic testing and zinc layer adhesion bend tests ensure zero peeling, flaking, or cracking during field fabrication. |
04 / 6-STAGE QUALITY CONTROL & GALVANIZING WORKFLOW
| ① BLACK FORMING | ② ACID PICKLING | ③ HOT-DIP DIPPING | ④ ZINC THICKNESS | ⑤ CNC THREADING | ⑥ PACKAGING |
| High-frequency ERW welding & sizing. | Degreasing and acid washing surface. | 450°C molten zinc bath immersion. | Magnetic gauge audit for zinc coating. | Thread coupling or roll grooving. | Hexagonal bundling with caps. |
05 / PACKAGING, MARKING & EXPORT STANDARD
| Packaging Category | Standard Handling & Protection |
| Bundling (≤ 4" OD) | Hexagonal seaworthy bundles tightly bound with steel straps and fitted with 2 nylon lifting slings for crane loading. |
| End Protection | Threaded ends equipped with plastic caps and galvanized couplings; grooved ends protected with rubber ring wraps. |
| Surface Protection | Passivation oil treatment to prevent white rust (wet storage stain) during ocean transit. |
Standard Pipe Stencil Marking Format:
============================================================
[BRAND NAME] ASTM A53 GRADE B HDG ERW
OD 2" (60.3MM) SCH 40 WT 3.91MM L=6000MM
ZINC COATING: 500 G/M2 HYDRO TEST PASS
MADE IN CHINA
============================================================
06 / FREQUENTLY ASKED QUESTIONS (FAQ)
Q1: What is the lifespan of hot-dip galvanized steel pipe outdoors?
A: With a zinc coating of ≥ 500 g/m² (approx. 70–85 μm), our HDG steel pipes provide an expected maintenance-free service life of 25 to 50+ years in rural and urban environments, and 15–25 years in harsh coastal/industrial atmospheres.
Q2: What is the difference between BS 1387 Class A, B, and C?
A: They denote wall thickness and pressure ratings: Class A (Light, brown color-band), Class B (Medium, blue color-band, most popular for general water/gas piping), and Class C (Heavy, red color-band, for high-pressure industrial lines).
Q3: How do you prevent "White Rust" during ocean transportation?
A: We apply automated environmental chromate passivation or light anti-rust oil post-galvanizing, store bundles in ventilated indoor warehouses, and pack them in waterproof woven wraps on request.
Q4: Can you provide customized threaded ends with couplings and roll grooves?
A: Yes. We can furnish one end threaded with coupling and the other end with plastic cap per ASTM A53, or supply precision roll grooved pipes compliant with AWWA C606 for rapid fire sprinkler installations.
? FACTORY TRUST & GUARANTEE
? DIRECT MILL PRICING (Massive Ready Stock) | ?️ ZINC COATING ≥500G/M² (Long Lifespan Guarantee) | ? CNC THREAD & GROOVE | ? EN 10204 3.1 MTC
