Welding is an essential component of many essential manufacturing processes, and back purging is an essential element of welding that helps improve the quality of the welds. According to the 2019 report of the American Welding Society, nearly 7 million people in the United States are employed in the field of welding, with over 17% of them holding Bachelor’s, Master’s or doctoral degrees in the specialty.
Despite the prevalence, there are still some who don’t know much about the technicalities of welding. One such important process, is back purging.
Back purging is a crucial approach in welding that helps reduce the defects in the weld joint, improves the integrity and quality of the weld, and thus aids in decreasing potential accidents and liabilities. In this article, we’re going to explore the idea of back purging in detail, discussing why is it done, how it’s performed, and its various applications.
What Is Back Purging In Welding?Welding is an important industrial process used to join two or more pieces of material together.
Welders use a variety of techniques to ensure that their welding is as strong and reliable as possible. One of these techniques is back purging, a process in which the backside of a weld is purged with an inert gas in order to prevent it from becoming contaminated. Back purging is used in welding processes such as GTAW (TIG Welding), GMAW (MIG Welding) and SMAW (Stick Welding).
It is also used in many other welding processes, such as oxy-fuel welding. The process involves using an inert gas, such as argon or nitrogen, to purge the back side of the weld. This prevents air from entering the weld, which can lead to contamination, cracks, and other issues.
Why Is Back Purging Necessary?Back purging is necessary because air contains oxygen, which can cause significant problems when welding.
Oxygen reacts with the molten metal and can form oxides, which will reduce the strength of the weld. It can also cause welding spatter and create porosity, or small holes in the weld.
All of these things can significantly reduce the strength and quality of the weld. In addition, air can also cause the weld to discolor or oxidize. This discoloration can be unsightly and make it difficult to judge the weld quality.
All of these issues can be avoided by purging the back side of the weld with an inert gas.