Submerged Arc Welding (SAW)
Submerged arc welding (SAW) is a type of arc welding process that is commonly used in heavy-duty industrial applications. This welding process involves the formation of an arc between a continuously-fed electrode and the workpiece. The arc is completely submerged under a layer of granular flux, which helps to protect the weld from atmospheric contamination and also provides additional shielding.
The SAW Process
The SAW process typically involves the following steps:
- Preparing the workpiece: The workpiece must be thoroughly cleaned and prepared before welding can begin. This includes removing any dirt, rust, or other contaminants that could interfere with the welding process.
- Setting up the equipment: The welding equipment, including the power source, wire feeder, electrode, and flux hopper, must be set up and configured for the specific welding job.
- Starting the arc: The arc is started by bringing the electrode into contact with the workpiece, and then slowly lifting it up to create a gap between the two.
- Submerging the arc: Once the arc is established, the flux hopper is activated, and the arc is completely submerged under a layer of granular flux.
- Welding the joint: The electrode is continuously fed into the joint, melting both the electrode and the base metal. As the molten metal cools, it solidifies and forms a bond between the two pieces.
Advantages of SAW
There are several advantages to using SAW for welding applications, including:
- High productivity: SAW is a highly efficient welding process that can be used to weld large, thick sections of metal in a single pass.
- Excellent weld quality: The submerged arc process produces high-quality welds with minimal defects, thanks to the protective layer of flux that helps to prevent contamination and oxidation.
- Good penetration: SAW is capable of penetrating deep into the base metal, resulting in strong, durable welds.
- Reduced fumes and spatter: Because the arc is completely submerged, there is less spatter and fumes generated during the welding process, resulting in a cleaner work environment.
Disadvantages of SAW
While there are many advantages to using SAW for welding applications, there are also some drawbacks to consider, including:
- High setup costs: The equipment and materials required for SAW can be expensive, which may not make it a practical choice for small welding jobs.
- Limited mobility: Because the electrode and flux hopper are fixed in place, SAW is not suitable for welding in tight spaces or in hard-to-reach areas.
- Complex setup: The setup and configuration of the equipment required for SAW can be complex and time-consuming, requiring skilled operators to ensure proper setup and operation.
Applications of SAW
SAW is commonly used in heavy-duty industrial applications, including:
- Structural steel fabrication
- Pipe welding
- Mining equipment
- Pressure vessel fabrication