Q235B galvanized steel pipe is a carbon steel pipe made from Q235B grade strip steel, enhanced with a protective zinc coating to improve corrosion resistance.
It is widely used in construction, plumbing, liquid transport, and structural applications. Galvanized pipes can be produced as hot-dip galvanized or electro-galvanized, offering options for different budgets and durability requirements.
Hot-dip Galvanized (HDG): Thick and uniform zinc coating, strong adhesion, long service life, superior corrosion resistance.
Electro-galvanized (EG): Lower cost, smoother surface is less uniform, and corrosion resistance is lower than HDG.
Specifications
Q235B galvanized steel pipes are available in a variety of nominal diameters (DN) and wall thicknesses to suit diverse applications:
| Nominal Diameter (DN) | Wall Thickness (mm) | Nominal Diameter (DN) | Wall Thickness (mm) |
|---|---|---|---|
| DN15 | 1.8 – 2.75 | DN80 | 2.2 – 3.25 |
| DN20 | 1.8 – 2.5 | DN100 | 2 – 4 |
| DN25 | 1.8 – 3.25 | DN125 | 2.5 – 4 |
| DN32 | 1.8 – 3.5 | DN150 | 2.5 – 4.5 |
| DN40 | 1.8 – 3.5 | DN200 | 2.75 – 6 |
| DN50 | 1.8 – 3.25 | DN200 | 5 – 6 |
Wall thickness and diameter ranges can be customized to meet project-specific requirements.
Chemical Composition
The chemical composition ensures Q235B steel pipes have good weldability, mechanical strength, and corrosion resistance:
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N |
|---|---|---|---|---|---|---|---|---|---|
| Q235 | – | – | – | – | – | – | – | – | – |
| 304L | 0–0.03 | 0–2 | 0–1 | ≤0.045 | ≤0.03 | 18–20 | – | 9–11 | – |
| 304H | 0.04–0.1 | – | – | 0.045 | – | 18–20 | – | 8–10.5 | – |
Note: 304/304L/304H are stainless steel references for comparison, showing typical tensile and hardness properties.
Mechanical Properties
| Grade | Tensile Strength (MPa) | Yield Strength (0.2%, MPa) | Elongation (% in 50mm) | Hardness (HR B / HB) |
|---|---|---|---|---|
| 304 | 515 | 205 | 40 | 92 / 201 |
| 304L | 515 | 205 | 40 | 90 / 187 |
| 304H | 515 | 205 | 40 | 92 / 201 |
Key Advantages:
Good ductility and plasticity
Excellent weldability
Moderate corrosion resistance (enhanced with galvanization)
Processing Technology
Q235B galvanized steel pipes are produced using high-quality strip steel and advanced processing:
Galvanization:
Hot-dip galvanized (HDG): Thick zinc coating, uniform adhesion, long lifespan.
Electro-galvanized (EG): Cost-effective, thinner coating, moderate corrosion protection.
Pipe Fabrication:
Small-diameter welded steel pipes (oxygen blowing method)
Materials: Q235B steel strips (also 08, 10, 15, 20 steel)
Optional aluminizing treatment to enhance corrosion protection
Applications
Q235B galvanized steel pipes are widely used across industries:
Water and Gas Transportation: Plumbing, pipelines, and industrial fluid systems.
Construction: Structural frameworks, scaffolding, support beams.
Mechanical and Manufacturing: Shafts, rods, hooks, couplers, and mechanical tubing.
General Engineering: Low-pressure containers and non-critical mechanical structures.
Q235B galvanized steel pipe is a versatile, cost-effective solution for industrial, commercial, and civil applications. By selecting the proper galvanization method (hot-dip or electro-galvanized), designers and engineers can balance budget, durability, and corrosion resistance according to project requirements.
