The welding practices commonly used in manufacturing coiled tubular products are described below.
- Gas Metal-Arc Welding
The welding process that produces coalescence of metals through heat generated by an arc (or arcs) created between a continuous consumable electrode and the work product. All gas used for shielding during the welding process is externally supplied and may be pure inert gas or a mixture of inert gases. Gas metal-arc welding does not require pressure, and the electrode provides the filler metal.
- Gas Tungsten Arc Welding
The welding process that produces coalescence of the metals through heat generated by an arc created between a single tungsten electrode and the work product. Gas tungsten arc welding does not require pressure, and filler metal may or may not be used. Pure inert gas is used for shielding during the welding process.
- High-Frequency Induction Weld (Seam)
A longitudinal seam weld produced through electric induction welding, where the heat for welding is generated by resistance to flow of electric current, and the edges to be welded are mechanically pressed together. This process does not use filler metal.
- Plasma Arc Welding
The welding process that produces coalescence of metals through heat generated by a constricted arc created between a continuous consumable electrode and the work product, or the continuous consumable electrode and a constricted nozzle. The gas used for shielding during the welding process is provided by the hot ionized gas discharging from the torch and may be supplemented by additional pure inert gas or a mixture of inert gases. Plasma arc welding may or may not use pressure in creating the weld, and the electrode provides the filler metal.
- Skelp-End Weld
A weld which is used to join skelp ends together. Skelp-end welds are performed on flat skelp and are typically made using plasma arc welding methods in accordance with qualified welding procedures.