Q235 steel is a plain carbon structural steel with a yield strength of approximately 235 MPa, which can vary depending on material thickness. The designation "Q" represents the material's yield point, while "235" indicates its approximate yield strength in megapascals.
Galvanized Q235 steel pipes do not require special process treatments, such as preheating or post-welding heat treatment, making them cost-effective and efficient for industrial use.
These pipes exhibit excellent robustness, weldability, and plasticity, retaining strength even under bending at low temperatures. Q235 galvanized steel pipes are widely applied in construction, engineering, and mechanical industries.
Common uses include factory buildings, steel bars, towers, boilers, bridges, containers, automobiles, and various welded structures. They also serve as reliable mechanical components.
All GI Q235 pipes are subject to strict quality control, with available test certificates and third-party inspections to ensure performance across diverse environmental conditions.
Specifications
Standards: ASTM / ASME
Galvanized Coating Types:
Hot-Dip Galvanized
Cold Galvanized / Electric Galvanized
Zinc-Coated
Powder-Coated
Epoxy-Coated
PVC-Coated
Galvanized Standard: EN ISO 1461
Nominal Diameter: 1/2″ – 4″ (DN15–DN100)
Nominal Wall Thickness: 2.0 mm – 4.5 mm
Test Pressure Index:
Dia 10.2 mm – 168.3 mm: 3 MPa
Dia 177.8 mm – 323.9 mm: 5 MPa
Zinc Coating Thickness:
Hot Galvanized: 35 μm – 650 μm
Cold Galvanized: 5 μm – 15 μm
Pipe Grades: ASTM A53 Grade B & C, Seamless; ASTM A36 Grade B, Seamless
Manufacturing Process (Seamless Galvanized Q235 Pipes)
Pickling
Washing
Plating
Drying
Hanging Plating
Cooling
Chemical Treatment
Cleaning & Grinding
Hot-Dip Galvanizing Finish
Coating Appearance Options: Shiny, Spangled, Matte Grey, Shiny & Dull
Testing: Laboratory testing, magnetic gauge test reports
Chemical Composition of Q235 Steel Pipes
| Grade | Quality | C % | Si % | Mn % | P % | S % |
|---|---|---|---|---|---|---|
| Q235A | A | ≤0.22 | ≤0.35 | ≤1.4 | ≤0.045 | ≤0.05 |
| Q235B | B | ≤0.20 | ≤0.35 | ≤1.4 | ≤0.045 | ≤0.045 |
| Q235C | C | ≤0.17 | ≤0.35 | ≤1.4 | ≤0.04 | ≤0.04 |
| Q235D | D | ≤0.17 | ≤0.35 | ≤1.4 | ≤0.035 | ≤0.035 |
Note: Q235B carbon content (C) can be ≤0.22% upon agreement.
Mechanical Properties
| Grade | Thickness (mm) | Yield Strength (MPa) | Tensile Strength (MPa) | Elongation (%) | Impact Energy (J) |
|---|---|---|---|---|---|
| ≤16 | ≤16 | ≥235 | 370–500 | ≥26 | – |
| >16–40 | >16–40 | ≥225 | 370–500 | ≥26 | ≥27 @ 20°C |
| >40–60 | >40–60 | ≥215 | 370–500 | ≥25 | ≥27 @ 0°C |
| >60–100 | >60–100 | ≥215 | 370–500 | ≥24 | ≥27 @ -20°C |
| >100–150 | >100–150 | ≥195 | 370–500 | ≥22 | – |
| >150–200 | >150–200 | ≥185 | 370–500 | ≥21 | – |
Deoxidation Methods: F, Z, TZ depending on grade
International Equivalents of Q235 Steel
| China | USA | Germany | Japan | France | UK | ISO |
|---|---|---|---|---|---|---|
| Q235A | Gr.D (σS230 MPa) | Ust37-2 / RSt37-2 | SS440 / SM400A | 080A15 | E235B | S235JR |
| Q235B | Gr.D (σS230 MPa) | S235JR / S235JRG1 | SS440 / SM400A | 080A15 | E235B | S235JR |
| Q235C | Gr.D (σS230 MPa) | S235JO | SM400A / SM400B | S235JO | 080A15 | E235C |
| Q235D | Gr.D (σS230 MPa) | S235J2G3 / J2G4 | SM400A | S235J2G3 / J2G4 | – | E235D |
