GB/T 700-2006 Grade C steel is a recognized material grade for manufacturing Longitudinal Submerged Arc Welded (LSAW) pipes. This corresponds to the Q235C steel grade, which offers enhanced low-temperature performance compared to Grades A and B, making it suitable for more demanding structural applications in colder environments .
| , manufactured using JCOE, UOE, or similar forming processes . | |
| GB/T 700-2006: Carbon Structural Steels . | |
| Q235C. The "Q" stands for Yield Strength, "235" indicates the minimum yield strength in MPa, and "C" denotes the quality grade with specified impact requirements at 0℃ . | |
| 0.17 | |
| 0.35 | |
| 1.40 | |
| 0.040 | |
| 0.040 | |
| >= 235 MPa (for thickness <= 16mm) | |
| 370-500 MPa | |
| Impact Energy (Charpy V-notch): >= 27 Joules at 0℃ | |
| 219 mm to 2500 mm+ (approx. 8" to 100"+) | |
| 5 mm to 25 mm+ | |
| 3 m to 18 m (customizable) | |
| 1. Steel plate selection and edge milling. 2. Edge crimping and forming using JCOE or UOE processes. 3. Internal and external submerged arc welding. 4. Mechanical expanding (for UOE/JCOE). 5. Non-destructive testing (Ultrasonic, X-ray). 6. Hydrostatic testing. 7. End facing and beveling. |
|
| Structural supports in colder climates; building components requiring guaranteed 0℃ impact toughness; bridge components; general engineering structures exposed to low ambient temperatures. | |
| Mill Test Certificate typically provided as per project requirements. |
: In the GB/T 700-2006 standard, the letter C indicates a specific with stricter controls on phosphorus and sulfur compared to Grades A and B. The defining characteristic of Grade C is that it guarantees a minimum impact energy of 27 Joules at 0℃, making it the appropriate choice for applications in colder environments where Grade B's room-temperature impact guarantee (+20℃) is insufficient .
Comparison of Q235 Grades:
| Q235A | General structures, low-pressure fluids, non-critical applications | |
| Q235B | +20℃ (27J min) | |
| Q235C | 0℃ (27J min) | |
| Q235D | -20℃ (27J min) |
: GB/T 700-2006 has been superseded by GB/T 700-2019. It is recommended to confirm which version year is required for your project.
: Q235C maintains excellent weldability due to its low carbon content (0.17% max), typically not requiring preheating under normal conditions, which reduces fabrication costs.
GB/T 700-2006 Grade C (Q235C) LSAW pipe
temperatures around or below freezing (0℃)
guaranteed impact toughness at 0℃
where Grade B's room-temperature guarantee is inadequate
For most general construction in mild climates, Grade B (Q235B) is sufficient and more economical. For severe cold environments below -20℃, Grade D (Q235D) would be required.
GB/T 700-2006 Grade C (Q235C) LSAW pipe is a reliable choice for structural applications requiring guaranteed impact toughness at 0℃, offering an intermediate option between general-purpose Grade B and cold-weather Grade D.
