What are some common causes of porosity defects in 3D welding?

1. Material Factors
Welding material problems: Welding rods or wires are damp or contaminated with oil, releasing gas when heated.
Base material problems: The workpiece surface contains impurities such as oil, moisture, and rust, which decompose and produce gas during welding.
2. Improper Process Parameters
Mismatched current/voltage: Insufficient current or excessive voltage (too long arc) leads to rapid cooling of the weld pool, preventing gas from escaping.
Excessive welding speed: The weld pool exists for a short time, and the gas is not fully expelled.
3. Insufficient Protection Measures
Shielding gas problems: Insufficient gas purity, inappropriate flow rate (too high or too low), or pipeline leakage, leading to air intrusion into the weld pool.
Environmental interference: High wind speed and high humidity disrupt the gas shielding effect.
4. Operation and Design Problems
Unreasonable groove design: Improper groove angle or gap leads to gas retention.
Non-standard operation: Excessive arc length, unstable welding technique, or lack of preheating affects gas escape.