Causes of pores in gas shielded welding and methods to prevent them
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Causes: ① Insufficient CO2 gas flow (excessive air). ② Air mixing into the CO2 gas. ③ The shielding gas being blown away by wind. ④ The nozzle being blocked by splatter particles. ⑤ The gas purity not meeting requirements. ⑥ The area to be welded being too dirty, with dirt and paint present. ⑦ Excessive distance between the nozzle and the workpiece. ⑧ The welding wire being bent. ⑨ Air being drawn into the welding area.Solutions: ① Check whether the gas flow rate is appropriate (15–25 L/min); verify there are no leaks in the gas pipes and that the pipe connections are secure. ② Ensure the pressure in the gas cylinder is above 1 MPa. ③ Windbreak measures should be taken where the wind speed exceeds 2 m/s. ④ Remove splatter particles from the nozzle (it is best to use a splatter prevention agent). ⑤ Use qualified CO2 gas. ⑥ Clean off oil, rust, and water from the surface of the workpiece. ⑦ The distance is usually 10–25 mm; it should be adjusted according to the current level and the diameter of the nozzle so that the arc burns at the center of the nozzle. ⑧ Straighten the welding wire. ⑨ When welding in a groove, if the welding torch is tilted, the gas flows in one direction, allowing air to enter from the opposite direction; when welding circumferential seams, the gas also flows in one direction, making it easy for air to enter, so the welding torch should be aligned with the center of the circumferential seam.
The main reasons for pores in gas shielded welding are as follows: 1. Insufficient CO2 gas flow: If the flow rate of CO2 gas is too low, it is not possible to provide effective protection for the weld, which leads to the formation of pores. 2. Air mixing into CO2: During welding, if air enters the CO2 gas, it can affect the quality of the weld and cause porosity issues. 3. The shielding gas is blown away by the wind: If there is a strong wind at the welding site, it will disperse the shielding gas, preventing adequate protection and resulting in pores. 4. The nozzle is blocked by spatter particles: Spatter is generated during welding, and if the nozzle becomes clogged with these particles, it can affect gas flow and lead to pores. 5. Gas purity does not meet requirements: Using CO2 gas that does not meet the standards, which may contain impurities, can also lead to the formation of pores. 6. The area to be welded is too dirty: If the welding area is not cleaned before welding, and if grease, dirt, paint, or similar substances are present on it, it will affect the quality of the weld and cause pores. 7. Excessive distance between the nozzle and the workpiece: A large distance between the nozzle and the workpiece leads to unstable gas flow, preventing adequate protection and increasing the likelihood of porosity. 8. Welding wire bending: If the welding wire is bent, it can affect the stability of the arc and also lead to porosity issues. 9. Air entrainment in the welding area: During welding, if air gets into the area surrounding the weld, it can also lead to the formation of pores. To prevent pores in gas shielded welding, we can take the following measures: 1. Check whether the gas flow rate is appropriate, generally ranging from 15 to 25 L/min ； Check for any leaks in the air tube and ensure that the tube connections are secure. 2. Ensure that the air pressure in the cylinder is greater than 1 MPa. 3. In cases of high wind speeds, wind protection measures should be taken to prevent the protective gas from being blown away. 4. Clean the splatter particles on the nozzle in a timely manner; it is best to use a specialized anti-splatter agent. 5. Use high-purity CO2 gas that meets the requirements. 6. Clean the area to be welded before welding, removing impurities such as grease, rust, and water. 7. Control the distance between the nozzle and the workpiece, which is generally 10~25 mm; adjust it according to the current and nozzle diameter to ensure that the arc burns at the center of the nozzle. 8. Straighten the welding wire to ensure arc stability. 9. Pay attention to the air flow near the welding area to prevent air from being drawn into it and causing pores. .