What is a recommended guideline for setting post flow rates in GTAW?

In Gas Tungsten Arc Welding (GTAW), post flow is crucial for protecting the tungsten electrode and the weld area after the arc has been extinguished. Maintaining an adequate gas coverage during this period prevents contamination and oxidation of the weld pool and electrodes. The recommended guideline for setting post flow rates is to use 1 second of post flow for every 10 amps of operating current. This ratio ensures that the torches and weld pools receive sufficient shielding gas to cool effectively without introducing impurities.

This guideline is particularly important as it balances adequate cooling with a minimized risk of contamination. If the post flow time is too short, there may not be sufficient protection, leading to defects in the weld or damage to the electrode. Conversely, excessively long post flow may waste shielding gas unnecessarily and could potentially cool the weld too rapidly, impacting the final properties of the weld. Thus, adhering to the 1 second for every 10 amps of operating current allows for optimal results in GTAW processes.