I. Overview of BS 1387 Galvanized Steel Pipes
BS 1387 is a British standard specifically regulating the dimensions, wall thickness, tolerances, and mechanical properties of galvanized welded steel pipes. This standard is widely used in water supply pipelines, gas pipelines, compressed air systems, and building structural supports.
Main Features:
- Manufacturing Process: Uses ERW high-frequency welding (small diameter) or SAW submerged arc welding (large diameter) to ensure weld quality.
- Outer Diameter and Wall Thickness: Standard outer diameters of 15 – 219 mm, wall thickness of 1.2 – 12.5 mm (light/medium/heavy).
- Surface Treatment: Hot-dip galvanizing (GI), with optional painting, rust-proof oil, or anti-corrosion coating to ensure long-term corrosion resistance.
- Tolerances and Quality: Outer diameter ±0.8%, wall thickness ±12.5%, length ±10 mm; material certificates (MTC) are provided, meeting the mechanical performance requirements of the steel grade.
- Application Areas: Industrial water supply, gas, air transportation, building supports, and mechanical structure installation; simple and reliable construction.
Advantages:
- Corrosion resistant, long service life
- Standardized dimensions, facilitating engineering design and installation
- Multiple wall thicknesses and lengths available to meet different working conditions
II. Common Steel Grades and Materials for BS 1387 Galvanized Steel Pipes
| Common Steel Grade | Material Description | Typical Applications |
|---|---|---|
| ST37 / S235 | Ordinary carbon structural steel, low carbon, moderate strength | Suitable for general water, gas, and air pipelines, as well as light structural applications |
| ST44 / S275 | Medium carbon structural steel, higher strength | Medium-pressure pipelines, general machinery structures, and supports |
| ST52 / S355 | High-strength low-alloy steel | High-pressure pipelines, building structures, and heavy machinery frameworks |
| 16Mo3 | Low-alloy carbon steel with molybdenum | High-temperature medium-pressure fluid transport, such as steam, water, and air |
| 13CrMo44 | Low-alloy chromium-molybdenum steel | High-temperature, high-pressure pipelines, chemical and industrial boiler systems |
III. Chemical Composition and Mechanical Properties of BS 1387 Galvanized Steel Pipes
i. Chemical Composition (Common Steel Grades)
| Steel Grade | C Carbon (%) | Mn Manganese (%) | P Phosphorus (%) | S Sulfur (%) | Others |
|---|---|---|---|---|---|
| ST37 | ≤ 0.17 | 0.30 – 0.60 | ≤ 0.045 | ≤ 0.045 | — |
| ST44 | ≤ 0.20 | 0.30 – 0.80 | ≤ 0.045 | ≤ 0.045 | — |
| ST52 | ≤ 0.22 | 0.70 – 1.20 | ≤ 0.035 | ≤ 0.035 | — |
| 16Mo3 (Low Alloy Steel) | 0.12 – 0.20 | 0.30 – 0.60 | ≤ 0.035 | ≤ 0.035 | Mo 0.25 – 0.35 |
| 13CrMo44 (Low Alloy Steel) | 0.08 – 0.15 | 0.40 – 0.70 | ≤ 0.035 | ≤ 0.035 | Cr 0.80 – 1.10, Mo 0.25 – 0.35 |
ii. Mechanical properties
| Steel Grade | Yield Strength Re (MPa) | Tensile Strength Rm (MPa) | Elongation A (%) | Impact Toughness KV (J) |
|---|---|---|---|---|
| ST37 | ≥ 235 | 360–500 | ≥ 22 | ≥ 27 (20℃) |
| ST44 | ≥ 275 | 410–560 | ≥ 20 | ≥ 27 (20℃) |
| ST52 | ≥ 355 | 490–630 | ≥ 18 | ≥ 27 (20℃) |
| 16Mo3 | ≥ 280 | 360–500 | ≥ 20 | ≥ 40 (20℃) |
| 13CrMo44 | ≥ 300 | 400–550 | ≥ 20 | ≥ 40 (20℃) |
IV. BS 1387 Galvanized Steel Pipe Selection and Procurement Recommendations
- Determine Application and Operating Conditions
- Water supply pipelines: Lightweight or medium-weight ST37/ST44 galvanized pipes are sufficient.
- Gas pipelines, compressed air systems: Medium-weight or heavy-weight ST44/ST52 galvanized pipes are recommended.
- High-temperature and high-pressure fluids: Choose low-alloy steel 16Mo3 or 13CrMo44.
- Outdoor or corrosive environments: Hot-dip galvanized (GI) or additional anti-corrosion coating is mandatory.
- Select the Appropriate Specifications
- Outer diameter: Choose 15–219 mm based on flow rate and installation requirements.
- Wall thickness: Lightweight 1.2–3.2 mm, medium-weight 3.25–6.3 mm, heavy-weight 6.5–12.5 mm.
- Small-diameter pipes are usually ERW welded, while large-diameter pipes can use SAW submerged arc welding.
- Material and Steel Grade Selection
- Confirm pressure capacity and operating temperature, and select the appropriate steel grade.
- Provide material certificates (MTC) to ensure that the steel pipes meet standard requirements.
- Surface Treatment
- Indoor: Rust-preventive oil is sufficient.
- Outdoor: Hot-dip galvanizing, painting, or anti-corrosion coating.
- Surface treatment directly affects the service life of the pipes.
- Suppliers and Quality Assurance
- Select qualified suppliers to ensure the steel pipes comply with BS 1387 standard.
- Testing items include dimensions, wall thickness, mechanical properties, non-destructive testing of welds, and chemical composition.
- Pressure testing or special anti-corrosion testing can be added according to project requirements.
- Packaging and Transportation
- Bundling, palletizing, or protective corners to prevent damage.
- Waterproof and rustproof packaging; customized packaging or special transportation methods can be arranged if necessary.
