How is the post flow of shielding gas typically set during GTAW?

In Gas Tungsten Arc Welding (GTAW), the post flow of shielding gas is crucial for protecting the tungsten electrode and the weld pool from contamination during the cooling phase after the arc is extinguished. The correct guideline for setting the post flow time is typically to allow 1 second of gas flow for every 10 amps of welding current used.

This ratio ensures that there is sufficient shielding gas present to prevent oxidation and contamination of the weld area as it cools, which is particularly important in processes involving metals sensitive to atmospheric exposure, such as aluminum or stainless steel. The post flow helps maintain the integrity of the weld and the electrode, providing a protective atmosphere until the weld has cooled to a temperature that is no longer susceptible to reacting with the environment.

This method of determining post flow time provides a reliable and reproducible setting that aligns with the best practices in the industry for achieving high-quality welds.