What is the flow rate range for back purging during welding?

The flow rate range for back purging during welding is typically between 2.4 to 9.4 liters per minute (lpm). This range is important to achieve effective back purging, which serves to shield the back side of the weld from atmospheric contamination, particularly oxidation.

At this flow rate, there is enough inert gas, usually argon, to adequately displace air from the purging area without causing excessive turbulence, which could disturb the shielding gas coverage or lead to improper purging. Maintaining a flow rate in this range ensures a steady and controlled flow of gas, providing optimal protection for achieving high-quality welds.

Choosing a flow rate that is too low may result in insufficient purging, leaving the weld area vulnerable to contaminants. Conversely, a flow rate that is too high might create an unstable environment that doesn't allow for proper gas coverage or could lead to excessive turbulence, which can adversely affect the weld quality.