27 Jan Backinggas systems
During the welding of steel, oxidation occurs in the weld seam if oxygen reaches this area unhindered (10 ppm, 0.001% or less). The resulting oxidized surfaces are no longer corrosion-resistant, and further treatment is necessary. Removing oxidation by grinding also removes the metal’s passive protection against corrosion. In some cases such as pipe welding, removing oxidation after welding is difficult or impossible to do. Instead of removing oxidation, another solution is to prevent it from occurring in the first place. In essence, this is what purging tries to achieve. With purging, a gas is used to protect the weld seam until it has cooled to the point that oxidation no longer can occur. Usually, an inert gas, such as argon which is heavier than air, is used.
Conventional purge dams such as inflatable rubber bladders or cardboard discs traditionally must be placed far from the weld zone. Remote placement of the purge dams may require large amounts of pure gas to be introduced to fully displace the oxygen in the weld zone. To overcome these limitations, PGE minimizes the amount of gas and time needed to purge the weld zone properly.
The unique design of PGE in combination with the flexible sealing discs makes it the perfect choice in the workshop as well as on site. Use PGE for the welding of pipe to pipe, pipe to bend or pipe to flange.