Definition - What does Girth Welds mean?
Girth welds are the different types of arc welding processes applied in the joining of two pipes along the circumference during a phase construction of a pipeline depending on the ease of implementation and the environmental factor.
They are used in making circumferential welds in pipeline and underground systems. They are used in the pipeline industry in the following activities:
- Main-line welding
- Tie-in welding
- Repair welding
- Fabrication welding
Corrosionpedia explains Girth Welds
In girth welds, the welder has to make several passes to make it a perfect and sealed joint. The welder has to first make a root pass—the most difficult pass—at a specified speed. The second pass is a hot pass that increases the thickness of the fill. Finally, the third pass is the fill and cap pass that is made to finish the welding process by covering the joint.
The selection of the welding method begins at the mode of application such as:
- Manual arc welding – gas tungsten arc welding & shielded metal arc welding
- Semi-automatic arc welding – gas metal arc welding, flux-cored arc welding & submerged arc welding
- Mechanized arc welding
- Automatic arc welding – forge welding (friction welding & flash-butt welding), laser-beam welding
The mode of welding or the standards set for girth welds are determined by:
- The joint strength of the pipes based on the base material
- The joint strength based on the external conditions
- The method of pipe manufacturing process
- The pipe wall thickness and its diameter
- The length of the pipeline/cost
- The terrain and environmental factors
- The workmanship of the welder
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