Q: What are the core performance differences between Q235 and Q355?
A: Q235 has a yield strength ≥235MPa and a tensile strength of 370-500MPa; Q355 has a yield strength ≥355MPa and a tensile strength of 490-570MPa. Q355 has higher strength and better low-temperature toughness.
Q: Can Q235 be used in pressure vessels?
A: Only Q235D, after special certification, can be used in low-pressure cryogenic vessels. Special steels such as Q345R are commonly used.
Q: What is the difference between Q235 and 45 steel?
A: Q235 has low carbon (≤0.22%), good plasticity/weldability, and is used for structural components; 45 steel has medium carbon (0.42%-0.50%), high strength/hardness, and is used for shafts, gears, and other parts.
Q: What European/American grades correspond to Q235?
A: Approximately EN S235JR and ASTM A36.
Q: How is the weldability of Q235?
A: Low carbon content, excellent weldability, suitable for manual arc welding, CO₂ gas shielded welding, and submerged arc welding.