9.1 Submerged Arc Welding (SAW) Explained

Key Concepts of Submerged Arc Welding (SAW)

1. Definition

Submerged Arc Welding (SAW) is an arc welding process that uses a continuous wire electrode and a granular flux to produce a molten pool that joins metal. The arc and the weld pool are completely covered by the flux, which protects the weld from atmospheric contamination.

2. Principle of Operation

SAW operates by creating an arc between the wire electrode and the workpiece, which melts the wire and the base metal. The granular flux, which is fed onto the weld area, melts and forms a slag that covers the weld pool. This slag protects the molten metal from oxidation and provides a stable environment for the weld to solidify.

3. Equipment

The primary equipment used in SAW includes:

• Wire Feeder: Supplies the continuous wire electrode to the weld area.
• Flux Feeder: Delivers the granular flux to the weld area.
• Power Source: Provides the electrical energy to create the arc.
• Torch or Gun: Holds the wire electrode and flux delivery system.

4. Advantages

Advantages of SAW include:

• High Productivity: SAW can produce high deposition rates, making it suitable for high-volume production.
• High Quality Weld: The use of flux provides excellent protection against atmospheric contamination, resulting in high-quality welds.
• Reduced Fume and Spatter: The flux covers the weld area, reducing the amount of fume and spatter produced.
• Automation: SAW is highly suitable for automation, which can improve consistency and reduce labor costs.

5. Applications

SAW is widely used in various industries, including:

• Structural Steel: Used in the construction of buildings, bridges, and other large structures.
• Pipeline Construction: Suitable for welding large-diameter pipes used in oil and gas transportation.
• Heavy Equipment Manufacturing: Used in the fabrication of heavy machinery and equipment.
• Shipbuilding: Commonly used in the construction of ship hulls and other marine structures.

Examples and Analogies

Imagine SAW as a cooking process where the ingredients are protected by a layer of flour. Just as the flour prevents the ingredients from drying out, the flux in SAW prevents the weld from oxidizing.

Think of the wire feeder as a pasta machine. Just as the pasta machine continuously feeds dough through rollers, the wire feeder continuously feeds the wire electrode to the weld area.

Consider the flux feeder as a salt shaker. Just as a salt shaker evenly distributes salt, the flux feeder evenly distributes the granular flux over the weld area.

Visualize the power source as an oven. Just as an oven provides heat to cook food, the power source provides electrical energy to create the arc and melt the metal.

Picture the torch or gun as a chef's tool. Just as a chef's tool is used to handle ingredients, the torch or gun is used to handle the wire electrode and flux delivery system.