Q235B Carbon Structural Steel (GB/T 700): Chinese Standard
GB/T 700-2006 · Published: 2026-05-22 · Updated: 2026-07-07
Q235B is China's fundamental carbon structural steel under GB/T 700-2006 and one of the most produced steel grades globally. The 'Q' prefix denotes yield strength of 235 MPa minimum for thicknesses ≤16 mm. Grade B provides guaranteed Charpy...
Q235B is China's fundamental carbon structural steel under GB/T 700-2006 and one of the most produced steel grades globally. The 'Q' prefix denotes yield strength of 235 MPa minimum for thicknesses ≤16 mm. Grade B provides guaranteed Charpy V-notch impact toughness (≥27 J at +20°C), making it suitable for welded building structures and bridges. With approximately 0.12-0.20% carbon, Q235B welds well without preheat for sections under 30 mm.
Quick Facts
| Category | Carbon Steel |
| Standard | GB/T 700-2006 |
| Density | 7.85 g/cm³ |
| Yield Strength | 235 MPa (34 ksi) |
| Tensile Strength | 370-500 MPa (54-73 ksi) |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| ASTM A36 | Compare |
| S235JR | Compare |
| SS400 | Compare |
| E250 | Compare |
| St37-2 | Compare |
Related Comparisons
Related Materials
🧮 Material Weight Calculator
Calculate the weight based on this material's density: 7.85 g/cm³
Frequently Asked Questions
What is the difference between Q235A and Q235B?
Q235B requires guaranteed Charpy V-notch impact values (≥27 J at +20°C), while Q235A has no impact test requirement. Q235B also has tighter limits on sulfur. For welded structural applications, Q235B is the minimum recommended grade.
References & International Standards
- ASTM International. Standard Specifications for Steel & Metal Alloys. astm.org
- International Organization for Standardization (ISO). Metallic Materials — Cross-Reference Database. iso.org
- American Iron and Steel Institute (AISI). Steel Grade Designations & Equivalents. steel.org
- European Committee for Standardization (CEN). EN Steel Standards & Numbering System. cencenelec.eu