Galvanized steel pipes are carbon steel pipes coated with a zinc layer, effectively preventing corrosion and rust and extending their service life. They are produced using either hot-dip galvanizing or electro-galvanizing processes, with hot-dip galvanized steel pipes offering stronger rust resistance and zinc coating adhesion. Available in various diameters and shapes, they are widely used in construction, fire protection, and chemical industries.
As an experienced professional steel pipe manufacturer, Glory Steel‘s galvanized steel pipes strictly adhere to international standards such as BS 1387, ASTM A53, and GB/T 3091, boasting a service life of over 20 years. Custom wall thickness and length services are also available.
Specification
| Item | Galvanized steel pipe |
|---|---|
| Place of origin | Tianjin, China |
| Standard | ASTM, EN, JIS, GB, DIN |
| Technique | ERW, LSAW |
| Material | Q235/Q195/Q345(S235JR/S275JR/S355JR), A53 Grade A/B, A500 Grade A/B/C |
| Section Shape | Square tubes, rectangular tubes, round tubes, elliptical tubes |
| Surface Treatment | Hot Dipped Galvanized |
| Zinc layer | 30-275g/m² |
| Thickness | 1mm-30mm |
| Length | 2-12m, customizable |
| Certificate | CE, SGS, ISO9001, BV, API |
Production Video
Features Of Galvanized Steel Pipe
Applications of GI Pipes
- Building Structures: Scaffolding pipes, fire-fighting pipes, I-beam and truss support pipes, as well as streetlight poles and traffic sign poles.
- Fluid Transportation: Water supply and drainage pipes, fire sprinkler pipes, low-pressure gas transportation, oil and gas transportation, and agricultural irrigation water pipes.
- Electrical Applications: Common JDG and KBG conduits, electrical wiring conduits, and conductors for grounding devices.
- Industrial Applications: Warehouse racks, conveyor rails, ventilation and dust extraction ducts, and safety guardrail posts.
Application Recommendations
| Scenarios | Recommended specifications |
| Household railings and handrails | DN25×2.0 ~ DN40×2.5 |
| Agricultural greenhouse frames | DN32×2.5 ~ DN50×3.0 |
| General supports and shelves | DN40×3.0 ~ DN65×3.5 |
| Scaffolding auxiliary pipes | DN48×3.0 ~ DN60×3.5 |
| Factory columns (≤4 meters) | DN80×4.0 ~ DN100×4.0 |
| Heavy-duty beams (large spans) | ≥DN125×4.5 |
Classification Of Galvanized Steel Pipe
1. Classification By Coating Process
- Hot-dip galvanized pipe(HDG): Dipped in molten zinc (~450°C). Thick zinc coating, rough surface, excellent adhesion.
- Electro-galvanized pipe (pre-galvanized): Electrolytic zinc coating applied before tube forming. Thin coating (10‑30μm), smooth surface, tight dimensional tolerance.
2. Classification By Cross-Sectional Shape
- Galvanized round tubes: Most popular, OD 1/2″‑8″. For water, gas and structural support.
- Galvanized square tubes: Side 10‑200 mm. Even stress, for building frames & handrails.
- Galvanized rectangular tubes: e.g.20×40mm,50×100mm. Widely used for curtain walls and machinery parts.
- Galvanized shaped tubes:Custom elliptical, hexagonal profiles for railings & special equipment.
3. Classification By Welding Process
- ERW galvanized pipe (resistance welded): High‑frequency welding from steel coils. High output, consistent wall thickness.
- LSAW galvanized pipe (longitudinal submerged arc welded): Longitudinal seam, heavy wall, high pressure resistance, for large‑diameter industrial projects.
- Spiral-welded galvanized pipe: Welded from Hot Rolled steel strip in a spiral. High flexibility, suitable for long-distance pipeline transportation.
Mechanical Properties Comparison Table
| Standard | Grade | Tensile Strength | Yield Strength | Elongation |
|---|---|---|---|---|
| ASTM A53 | Grade A | 330 – 480 MPa | ≥ 170 MPa | ≥ 30% |
| ASTM A53 | Grade B | 415 – 550 MPa | ≥ 240 MPa | ≥ 20% |
| ASTM A500 | Grade B | ≥ 435 MPa | ≥ 290 MPa | ≥ 20% |
| ASTM A500 | Grade C | ≥ 483 MPa | ≥ 317 MPa | ≥ 23% |
| EN 10219 | S235JR | 360 – 510 MPa | ≥ 235 MPa | ≥ 26% |
| EN 10219 | S275JR | 410 – 560 MPa | ≥ 275 MPa | ≥ 22% |
| EN 10219 | S355JR | 470 – 630 MPa | ≥ 355 MPa | ≥ 21% |
| GB/T 3091 | Q195 | 315 – 430 MPa | ≥ 195 MPa | ≥ 33% |
| GB/T 3091 | Q235B | 370 – 500 MPa | ≥ 235 MPa | ≥ 26% |
| GB/T 3091 | Q345B | 470 – 630 MPa | ≥ 345 MPa | ≥ 21% |
ASTM A53 and GB/T3091 Corresponding Specification Table
| NPS | DN | OD, mm | Astm Sch40 | ASTM Sch80 | GB/T3091 Standard | GB/T3091 Thickened |
|---|---|---|---|---|---|---|
| 1/2″ | DN15 | 21.34 | 2.11 | 3.73 | 2.75 | 3.25 |
| 3/4″ | DN20 | 26.67 | 2.87 | 4.19 | 2.75 | 3.25 |
| 1″ | DN25 | 33.40 | 2.77 | 5.49 | 3.25 | 3.75 |
| 1-1/2″ | DN40 | 48.26 | 3.68 | 6.02 | 3.50 | 4.00 |
| 2″ | DN50 | 60.33 | 3.91 | 5.54 | 3.50 | 4.00 |
| 3″ | DN80 | 88.90 | 5.49 | 8.38 | 4.00 | 4.50 |
| 4″ | DN100 | 114.30 | 6.02 | 10.16 | 4.00 | 4.50 |
| – | DN32 | 42.4 | – | – | 3.25 | 3.75 |
| – | DN65 | 76.1 | – | – | 3.75 | 4.25 |
| – | DN150 | 168.3 | – | – | 4.50 | 5.00 |
| – | DN200 | 219.1 | – | – | 4.50 | 5.50 |
Note:
NPS: American standard nominal diameter, DN: Chinese standard nominal diameter, OD: actual outer diameter. Sch 40: Commonly used wall thickness grade in the American standard, corresponding to “ordinary wall thickness” in the Chinese standard.
Wall Thickness Representation Method
Hot‑dip galvanizing immerses pipe into molten zinc. Though costlier than cold‑dip galvanizing, it delivers superior corrosion resistance. All our galvanized pipes adopt hot‑dip galvanizing.
American Standard – SCH
SCH (Schedule) is the wall‑thickness marking under ASME B36.10/B36.19. Common grades include SCH10, SCH20, SCH40, SCH80, SCH100, SCH120, SCH140, SCH160. For identical NPS, higher SCH number means thicker pipe wall.
National Standard – DN
DN stands for Nominal Diameter, widely used in Chinese and international pipe standards. The DN figure is nominal designation, not the real physical diameter.
Wall thickness and load-bearing capacity table
| NPS | OD(mm) | WT (mm) | Compressive strength (tons) | Central bending strength (kg) |
| DN15 (1/2″) | 21.3 | 2.0 | ~2.5 | ~7 |
| DN20 (3/4″) | 26.9 | 2.0 | ~3.5 | ~13 |
| DN25 (1″) | 33.7 | 2.5 | ~5.2 | ~25 |
| DN32 (1-1/4″) | 42.4 | 2.5 | ~7.0 | ~42 |
| DN40 (1-1/2″) | 48.3 | 3.0 | ~9.0 | ~65 |
| DN50 (2″) | 60.3 | 3.0 | ~11.5 | ~110 |
| DN65 (2-1/2″) | 76.1 | 3.5 | ~16.5 | ~170 |
| DN80 (3″) | 88.9 | 4.0 | ~23.0 | ~260 |
| DN100 (4″) | 114.3 | 4.0 | ~31.0 | ~400 |
| DN125 (5″) | 139.7 | 4.5 | ~44.0 | ~610 |
| DN150 (6″) | 165.2 | 4.5 | ~52.0 | ~860 |
| DN200 (8″) | 219.1 | 6.0 | ~90.0 | ~1600 |
Formula For Weight Of Galvanized Pipe
Note: Calculation unit: mm, output weight per meter (kg/m)
Success Cases
FAQs
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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 hot-dip galvanized pipes; the most popular sizes are 1-inch, 2-inch, and 1 1/2-inch. Including round, square, rectangular, and oval pipes. As well as ASTM A53 Gr.B GI Pipe and GI culverts. With our high-quality products and services, we export to over 120 countries.
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