What can grossly unequal pressure of gases lead to in welding?

Grossly unequal pressure of gases in welding, particularly when using oxy-fuel equipment, can lead to a flashback. A flashback occurs when the flame from a welding or cutting torch travels back into the gas supply line, potentially reaching the gas cylinder. This situation can create very dangerous conditions, as it can ignite flammable materials or cause an explosion if the backflow is not adequately controlled.

The equipment typically has safety mechanisms, such as flashback arrestors, designed to prevent this occurrence. Maintaining equal pressure helps ensure proper combustion and reduces the risk of the flame moving in the reverse direction. Understanding this is crucial for safe practices in welding operations, as improper gas flow can lead not only to flashbacks but also to severe injuries or equipment damage.