What is the purpose of the pre-purge process in welding?

The pre-purge process in welding is primarily intended to clear oxygen from the weld zone. This is crucial, especially in Gas Tungsten Arc Welding (GTAW), as the presence of oxygen can lead to the formation of oxides on the weld surface, compromising the integrity and quality of the weld. By purging the area before beginning the welding process, the metal surfaces are better prepared for fusion, ensuring a cleaner weld and reducing the likelihood of imperfections such as porosity and inclusions.

Pre-purge helps create an inert atmosphere around the weld zone, which is particularly beneficial when working with materials like aluminum and stainless steel that are susceptible to oxidation. As a result, the success of the welding project is significantly enhanced by taking this preventative step before the actual welding begins.