What is the purpose of post purge in welding?

The purpose of post purge in welding is primarily to protect the weld pool and the tungsten electrode from contamination, which is crucial for ensuring the integrity of the weld. During the welding process, especially with techniques like Gas Tungsten Arc Welding (GTAW), the weld area is vulnerable to atmospheric contamination from oxygen and nitrogen, which can lead to defects such as porosity or oxidation in the weld.

Post purge involves continuing the flow of an inert shielding gas (like argon) around the weld area after the arc has been extinguished. This helps to displace any contaminants that might settle on the weld bead while it cools, effectively shielding the newly formed weld metal from the surrounding environment. Without this protective gas envelope, the quality of the weld can be compromised, affecting strength and corrosion resistance.

The other options do not accurately capture the primary function of post purge. Enhancing welding speed, cooling equipment, and controlling power source accuracy are not directly related to the benefits provided by post purge.