A36, Q235 and S235 are low-carbon structural steels from different standards. They overlap in typical strength and weldability but are not identical. Choose by your design standard first (ASTM, GB/T, EN), then confirm strength class, impact grade and available shapes.
At a glance (typical)
| Grade | Standard | Min yield | Tensile | Notes |
|---|---|---|---|---|
| A36 | ASTM A36/A36M | ~250 MPa | ~400–550 MPa | Plates & shapes common in NA |
| Q235 (A/B/C) | GB/T 700 | ~235 MPa | ~370–500 MPa | Subgrades differ (impact/de-oxidation) |
| S235 (JR/J0/J2) | EN 10025-2 | ~235 MPa | ~360–510 MPa | JR 20 °C, J0 0 °C, J2 −20 °C Charpy |
Values vary with thickness; confirm on the MTC. J-suffix indicates Charpy temperature for EN grades.
When to pick which
- ASTM/AISC route: A36 for shapes and plates; widely available and familiar in North America.
- EU/UK route: S235JR/J0/J2 to match Eurocode and CE; pick J2 for cold sites or dynamic loads.
- GB/T route: Q235B default; use Q235C/D for lower-temperature impact.
Weldability & forming
All three weld with low-hydrogen processes (E7018, GMAW solid). For tight bends in thicker plate, follow the mill’s minimum inside radius; properties shift with thickness and de-oxidation.
Tolerances & shapes
- A36: dimensions per ASTM A6.
- S235: EN 10029 (plates) or EN 10034/10056 (sections).
- Q235: GB/T 709 (plates) or GB/T 706/1591 (sections).
Spec lines (copy/paste)
- ASTM: A36 plate 10 mm × 2000 × 6000; tolerances per A6; 3.1 MTC.
- EN: S235J2 plate 10 mm × 2000 × 6000; impact −20 °C 27 J; EN 10029; 3.1 MTC.
- GB/T: Q235B plate 10 mm × 2000 × 6000; GB/T 709; 3.1 MTC.
Baoli Engineering Team · Reviewed Oct 31, 2025