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Electro gas welding

Joining process resulting from the continuous supply of a metal electrode, which is melted in the presence of a protective gas.

Illustration of Electro gas welding

The process

Before machining commences two water-cooling shoes [1] are placed on each side of the weld zone to prevent the melt flowing out during the welding process. The welding area is fed continuously with a wire [2], which also acts as electrode. To protect the melt against pollution a protective gas [3] is added, usually consisting of carbon dioxide. The workpiece and the electrode are connected to a power source, and this causes an electric arc. This creates high amount of heat energy, which leads to the electrode and parts of the workpiece to be melted [4]. The wire and its control mechanism is then raised as the melt solidifies and finally leave behind the desired weld joint.

In cases where a small weld is desired, and the accessibility exists, finishing in the form of grinding is applied.

Advantages and disadvantages
In comparison with alternative methods
Better visibility at the welding process
Faster start welding
better mechanical properties
High efficiency in the welding process
lower angle distortion
heat affected zones can be softened
heat affected zones can be brittle
The weld seam is less clean than the electro-slag welding
The weld seam has lesser cracks than electroslag welding
More porosity for thicker works
The overlap of liquid metal flows