Hot-dip galvanized steel pipe is made by immersing carbon steel pipe in molten zinc to form a zinc anti-rust layer on the pipe surface, extending the service life of the carbon steel pipe. It can withstand humid and corrosive outdoor environments. It is mainly used for water supply and drainage, fire protection pipelines, scaffolding pipes, and conduit pipes.
Glory Steel is a manufacturer and supplier of hot-dip galvanized steel pipes in China. We specialize in custom-producing Z30-Z275 zinc-coated structure pipes/fluid pipes/gas pipes/oil pipes, offering round/square/rectangular cross-sections, as well as cutting, welding, and bending services.
Specification
| Item | Hot-dip galvanized steel pipe |
| Material | Q195/Q235B/Q345B/Q355B/GR.B |
| Standard | GB/T 3091、ASTM A53 Gr.B、BS 1387、EN 10255 |
| Zinc layer | Z30-Z275 |
| Process | Hot Rolled Based, Cold Rolled Based, ERW |
| Certification | CE/ISO 9001/JIS/UL/MTC |
| Processing services | Welding, cutting, bending, threading, grooving, flange connection |
| Packaging | Bundling, Cardboard Boxes, Pallets |
| Delivery time | 8-14 days |
| MOQ | 10 tons |
Size parameter table
| Item | Q195/Q235B/Q345B hot-dip galvanized pipe |
| Pipe Diameter (Imperial) | 1/2″,3/4″,1″,1-1/4″,1-1/2″,2″-8″ |
| Nominal Diameter | DN15/DN20/DN25/DN32/DN40-DN200 |
| Wall Thickness | 1.0mm-6.0mm, SCH 40/SCH 80 |
| Length | 6 meters, 12 meters |
| Connection | Threaded, Grooved, Welded |
Features of HDG steel pipes
- Superior Corrosion Resistance: The hot-dip galvanized layer is typically 50-120μm thick (electro-galvanized only 5-20μm), ensuring a tight bond between the coating and the steel substrate, maintaining stability in humid, salt spray, and corrosive environments over long periods.
- Excellent Mechanical Properties: Made from high-quality carbon structural steel such as Q235 and Q345, it boasts high strength and toughness, exhibiting excellent impact resistance and high-pressure resistance.
- Long Service Life: Due to the thicker zinc coating, its service life far exceeds that of hot-rolled/cold-rolled carbon steel pipes or cold-galvanized pipes. Service life can reach 20-30 years.
- Convenient Installation and Maintenance: In addition to cutting and welding, it can also be cold-bent, flared, and reduced in diameter. The surface is smooth and clean, with low maintenance costs, eliminating the need for frequent rust prevention treatments. It also features low fluid resistance, enabling long-distance transportation.
Mechanical properties
| Performance Indicators | Parameter Range |
| Yield Strength | 235MPa-420MPa |
| Tensile Strength | 370MPa-550MPa |
| Elongation | 15%-30% |
| Impact Toughness | ≥27J |
| Zinc Coating Hardness | Approximately HV70-HV100 |
Application scenarios
- Building Structures: Used for scaffolding pipes, domestic drainage pipes, ranch and horse farm fence panels and fittings, and handrails.
- Municipal Engineering: Gas and heating pipelines, fire-fighting pipelines, sewage discharge, and underground pipeline protection.
- Industrial Production: Pipelines for transporting crude oil, petroleum, natural gas, and corrosive media; chemical equipment; mezzanine structural frames; and power towers.
- Agriculture & Transportation: Used as guardrails and bollards for bridges, roads, and railways; ventilation and drainage pipes for rail transit; and cable and wire conduits.
What is its production process?
The hot-dip galvanized steel pipe manufacturing process mainly includes black pipe pretreatment, fluxing, hot-dip galvanizing, coating adjustment, cooling, and post-treatment.
In simple terms, it involves first alkaline washing, acid washing, and rinsing to remove oil and iron oxide scale. Then, the pipe is immersed in molten zinc at approximately 450℃-500℃, forming a zinc-iron alloy layer on the steel surface. Excess zinc is removed by blowing from both inside and outside the pipe, followed by water cooling and passivation to prevent the formation of “white rust,” before inspection and packaging.
International standard grade equivalent material
| Chinese GB Grade | ASTM (US Standard) | DIN (German Standard) | EN 10025 (EU Standard) |
|---|---|---|---|
| Q195 | ASTM A53 Gr. A (Grade A) | St33 | S195JR |
| Q235B | ASTM A53 Gr. B (Grade B) | St37-2 | S235JR |
| Q345B (Old GB) | ASTM A53 Gr. C (Grade C) | St52-3 | S355JR |
| Q355B (New GB) | ASTM A53 Gr. C (Grade C) | St52-3 | S355JR |
Grade Mechanical Properties
| Steel Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Application Level |
|---|---|---|---|
| Q195 | ≥195 | 315 – 430 | Light Duty |
| Q235B | ≥235 | 375 – 460 | General Purpose |
| Q345B | ≥345 | 470 – 630 | High Strength |
| Q355B | ≥355 | 470 – 630 | High Strength |
Hot dip galvanized pipe vs electro-galvanized pipe
| Characteristics | Hot-dip galvanized pipe | Electro-galvanized pipe |
|---|---|---|
| Coating | Zinc-iron alloy layer | Physical adhesion |
| Coating Thickness | 50-120μm | 5-20μm |
| Appearance | Rough coating, silver-gray | Thin, bright, precise coating |
| Corrosion Resistance | Excellent | General |
| Cost | High | Low |
| Applications | Fire fighting, gas, steel structure | Automotive, precision instruments |
Why Choose Us?
- Direct-from-source steel pipe manufacturing plant, integrating welding and hot-dip galvanizing production for controllable costs and stable quality.
- Supports OEM/ODM customization, allowing for adjustments to length, wall thickness, pipe end treatment, and packaging markings.
- Rigorous testing of zinc layer thickness, water pressure, and straightness to meet export standards.
- Provides a full set of export documents, including CE, ISO, material certificates, and commodity inspection certificates.
- Suitable for full container load shipments, maximizing container volume and reducing logistics costs; available from ports worldwide.
FAQs
Glory Steel, located in Tianjin, China, is ISO 9001, ISO 14001, and CE certified, with an annual output of 100,000 tons. We specialize in producing galvanized square and round tubes and galvanized culverts. With our high-quality products and services, we export to over 120 countries.
Mon-Fri: 8:00 – 18:00 (GMT+8)
