Q: What are the commonly used welding electrode types for Q235?
A: E43 series (e.g., E4303). For important structures, E4315/E4316 basic welding electrodes offer better crack resistance.
Q: How to prevent porosity when welding Q235?
A: Dry the welding electrodes, clean off oil and rust, control the purity of the shielding gas, and use appropriate welding parameters.
Q: Is preheating required for Q235 welding?
A: For plates ≤40mm thick, preheating is generally not required at room temperature; for thick plates or low-temperature welding, preheat to 100-150℃ to prevent cold cracking.
Q: What are the cold bending properties of Q235?
A: Good cold bending properties, suitable for cold stamping and cold bending of steel sections (such as angle steel and channel steel).
Q: Can Q235 be heat-treated for strengthening?
A: Low-carbon steel has poor hardenability, and the tempering effect is limited; heat treatment is usually not required. For wear resistance, surface carburizing/quenching can be performed.