1 1/4″ Galvanized Steel Pipe (Commonly known as 1.25-inch galvanized pipe), Nominal Diameter DN32, Standard Outer Diameter 42.4mm. It is ERW high-frequency longitudinal welded carbon steel pipe with hot-dip zinc coating on the surface for superior rust resistance, widely used for steel structures, supports and low-pressure fluid transmission as a medium-diameter steel pipe.
Glory Steel is a direct export manufacturer of 1 1/4 inch hot-dip galvanized steel pipe. We strictly control weld quality, dimensional tolerance and zinc coating uniformity. We maintain stock for multiple wall thicknesses and support custom dimensions and deep processing.
Specification Table
| Item | 1 1/4″ Galvanized Steel Pipe |
|---|---|
| Nominal Size | 1 1/4″ (DN32) |
| Outer Diameter | 42.4 mm |
| Material Grade | Q195, Q235B, Q355B; ASTM A53 Grade A/B; EN S235JR / S355JR |
| Manufacturing Process | ERW Longitudinally Welded Pipes/Seamless Pipes, Hot-Dip Galvanized |
| Wall Thickness | 1.5mm – 3.75mm (Customizable) |
| Length | 1–12m fixed cut length |
| Zinc Coating | Standard 80–120g/㎡; High zinc coating available up to 200–300g/㎡ |
| Pipe Ends | Plain end / Threaded (BSPT/NPT) / Grooved / Beveled |
| Applicable Standards | ASTM A53/A53M, EN 10255, GB/T 3091 |
| MOQ | 10 Metric Tons |
Product Classification
- By manufacturing process: ERW welded galvanized steel pipe and seamless galvanized steel pipe. ERW welded galvanized pipe features higher cost performance and is the most popular option for project procurement. Seamless galvanized pipe is adopted for higher pressure and harsh working conditions.
- By wall thickness grade: Sch 40 standard wall thickness (approx. 3.56mm), the most commonly used grade; maximum reinforced wall thickness in stock up to 3.75mm.
- By pipe end type: Plain end pipe, threaded pipe, beveled pipe. Plain end is the most common and widely selected.
Mechanical Properties Reference
| Material Grade | Min Yield Strength | Min Tensile Strength | Min Elongation |
|---|---|---|---|
| Q195 | 195 MPa | 315 MPa | 26% |
| Q235B / S235JR | 235 MPa | 370 MPa | 26% |
| Q355B / S355JR | 355 MPa | 470 MPa | 21% |
Advantages
- Long-Term Corrosion Protection: The metallurgical bond layer formed by hot-dip galvanizing ensures more than 10 years of service in typical outdoor environments. A high-zinc coating is recommended for areas with high humidity and high salinity.
- Universal Compatibility: With tight tolerances and good roundness, these pipes provide excellent sealing when connected to fittings and threaded joints, and can be cut and drilled directly.
- Stable Pressure Resistance: High-frequency resistance longitudinal welding ensures pinhole-free welds, enabling the pipes to reliably withstand fluid pressure and meet the bending requirements of steel structures.
- Multiple Sizes in Stock: Standard wall thicknesses are kept in stock, and large orders can be quickly scheduled for production with on-time delivery.
Technical Reference Data
1. Theoretical Working Water Pressure for Different Wall Thicknesses
| Wall Thickness | Outer Diameter | Theoretical Working Water Pressure (MPa) | Application Note |
|---|---|---|---|
| 1.5mm | 42.4mm | 1.0 MPa | Low-pressure irrigation, static water delivery, not recommended for buried installation |
| 2.0mm | 42.4mm | 1.3 MPa | Open-air irrigation, low-pressure water supply & drainage |
| 2.5mm | 42.4mm | 1.6 MPa | Buried water transmission, common irrigation main pipe |
| 3.0mm | 42.4mm | 1.9 MPa | Working conditions with relatively high water pressure |
| 3.75mm | 42.4mm | 2.4 MPa | Reinforced pipe with optimal pressure resistance |
2. Theoretical Axial Compressive Bearing Capacity
Application: Greenhouse / fence posts, 6m full length, fixed at both ends, no eccentric load.
| Wall Thickness | Section Parameter | Axial Compressive Bearing Capacity (kN) | Selection Tip |
|---|---|---|---|
| 1.5mm | Thin wall | 11 kN | Only for transverse tie rods in low-wind zones. Not recommended for 6m high posts due to buckling risk |
| 2.0mm | Thin wall | 19 kN | Conventional farm greenhouse posts, low wind pressure areas |
| 2.5mm | Medium wall | 29 kN | Greenhouses in high wind areas, livestock fence posts |
| 3.0mm | Medium wall | 40 kN | Coastal projects with high wind pressure for posts |
| 3.75mm | Reinforced wall | 57 kN | Heavy-duty supports, high-load projects |
3. Theoretical Pipe Weight Table (6m per piece)
| Wall Thickness | Theoretical Weight per Meter | Total Weight per 6m Piece |
|---|---|---|
| 1.5mm | 1.97 kg/m | 11.8 kg |
| 2.0mm | 2.58 kg/m | 15.5 kg |
| 2.5mm | 3.18 kg/m | 19.1 kg |
| 3.0mm | 3.76 kg/m | 22.6 kg |
| 3.75mm | 4.62 kg/m | 27.7 kg |
4. 20GP Container Loading Reference (Standard length 6m/pc)
| Wall Thickness | Weight per 6m Piece | Reference Quantity for 20GP |
|---|---|---|
| 1.5mm | 11.8kg | Approx. 820 pcs |
| 2.0mm | 15.5kg | Approx. 620 pcs |
| 2.5mm | 19.1kg | Approx. 500 pcs |
| 3.0mm | 22.6kg | Approx. 420 pcs |
| 3.75mm | 27.7kg | Approx. 340 pcs |
Main Applications
- Irrigation & low-pressure fluid transmission for water supply & drainage (farm & park water pipelines).
- Greenhouse frame, support frame for livestock farm fencing.
- Light steel structure brackets, guardrails, balustrades and prefab house frames.
- Construction pipelines, mechanical components, outdoor engineering supports and conduit pipes.
Recommended Wall Thickness by Project Application
| Application Scenario | Recommended Wall Thickness | Description |
|---|---|---|
| Greenhouse tie rods, simple fence transverse supports | 1.5mm | Light load, indoor / low wind area, optimal cost |
| Greenhouse posts, orchard fence posts | 2.0mm | Outdoor normal wind load, most popular choice for farm projects |
| Greenhouses in high wind zones, livestock fence posts | 2.5mm | Resist strong wind, long-term outdoor service, better bending resistance |
| Low-pressure irrigation water supply, water supply & drainage pipes | 2.5~3.0mm | Guarantee fluid pressure resistance, reduce deformation, suitable for buried / open water delivery |
| Heavy-duty supports, coastal high wind pressure projects, Sch 40 conditions | 3.75mm | Reinforced wall, best bending & pressure performance |
FAQ
Q1: What is the outer diameter of a 1 1/4-inch galvanized steel pipe?
A: The standard outer diameter is 42.4 millimeters, with a nominal diameter of DN32; it is commonly referred to as a 1.25-inch pipe. BSPT and NPT thread specifications are available.
Q2: Can you provide material certificates?
A: We can provide EN 10204 Part 3.1 material certificates and galvanized coating test reports for every batch of products. We support third-party inspections.
Q3: Can the galvanized coating be customized?
A: The standard galvanized coating is 80–120 grams per square meter. For coastal projects with high salt fog exposure, it can be upgraded to 200–300 grams per square meter.
Glory Steel Plant, located in Tianjin, China, is an ISO 9001, and CE‑certified factory with an annual output of 100,000 tons. We specializing in the manufacture of galvanized pipes in a full range of sizes and cross-sections. Our best-selling products include 1-inch, 2-inch, and 3-inch round pipes, as well as galvanized square and rectangular pipes. Supply OEM/ODM solutions. With stable quality and comprehensive service, we export to over 120 countries.
