SubArc Welding Machines for Sale

Submerged arc welding (SAW), often referred to as sub arc welding, is a high-output welding process primarily used for thick steel sections and long, continuous welds.

It is most commonly found in heavy fabrication environments such as pipe manufacturing, pressure vessels and large structural components, where consistent weld quality and speed are essential.

In submerged arc welding, an electric arc forms between a continuously fed wire electrode and the workpiece.

A layer of granular flux is fed over the weld area, and as the flux melts, it forms a protective slag layer that shields the weld pool from contamination and helps stabilise the arc. Resulting in cleaner welds with less operator intervention and deeper penetration.

To learn more, read our submerged arc welding and applications guide.

The process is called “submerged” because the welding arc and molten weld pool are covered by a layer of granular flux during welding.

This flux shields the arc from the surrounding atmosphere, reducing spatter, fumes and arc visibility.

Advantages:

• High deposition rates - submerged arc welders can achieve high weld metal deposition rates, making them suitable for welding thick sections.
• High productivity - particularly effective for long, repetitive welds where speed and consistency are important.
• Good weld quality - SAW typically produces sound and high-quality welds with good mechanical properties. 

Disadvantages:

• Limited joint access - the process is mainly for flat and horizontal welding.
• Less flexible - most setups are fixed or semi-fixed (e.g. column & boom systems), so they’re not suited to site work.
• Initial set-up costs - due to the amount of equipment required, initial investment costs for SAW can be high compared to manual welding.

Submerged arc welding is commonly used for heavy fabrication applications involving thick steel plates and large-diameter components.

Typical applications include:

• Pressure vessel manufacturing
• Structural steel fabrication
• Pipe and pipeline welding
• Shipbuilding
• Wind tower production

The process is valued for its high deposition rates and consistent weld quality.

It is particularly suited to production environments where repeatability and throughput are more important than flexibility.

A typical submerged arc welding setup includes several components:

• A welding power source
• A wire feed system and welding head
• Granular welding flux
• A travel mechanism such as a welding tractor or column & boom system

Additional equipment, such as flux recovery systems, welding rotators or positioners, may also be used depending on the application.

The exact configuration will depend on whether the application involves flat plate welding, cylindrical components, or automated production lines like those for beam welding, for example.

Most submerged arc welding systems are mechanised or automated. Equipment such as welding tractors, column & boom systems, and automated beam lines allow the welding head to travel along the joint automatically.

Depending on the setup, systems can be configured for semi-automatic or fully automatic welding.

Common troubleshooting tips for sub arc welding include:

• Insufficient penetration - can be caused by low current or voltage settings, excessive travel speed, and inadequate joint preparation.
• Excessive penetration - can occur when current or voltage settings are too high, travel speed is too slow, or excessive joint preparation.
• Weld bead irregularities - occurs when there is uneven flux distribution, incorrect wire feed or voltage settings, or poor wire alignment.
• Porosity in the weld bead - can be caused by contaminated flux, moisture in the flux, or insufficient preheating.
• Arc instabilities or arc blow - can occur when there is magnetic interference, incorrect electrode polarity, or insufficient or excessive flux coverage.
• Slag inclusions – caused by improper flux coverage or incorrect travel speed.

Always refer to the equipment manuals and welding specifications to ensure all settings and parameters are correct.

To help you achieve success in your submerged arc welding process, take a look at these tips! 

• Joint preparation - ensure proper joint preparation, including bevel angle, root gap, and cleanliness. Good joint fit-up is crucial for achieving high-quality welds.
• Proper voltage and current settings: set the welding parameters, including voltage and current, according to the material thickness and joint configuration. Refer to welding procedure specifications (WPS) and adjust parameters as needed.
• Flux handling: store flux in a dry environment to prevent moisture absorption, which can lead to porosity and other welding defects. Use a flux recovery system to collect and recycle unused flux, reducing material waste.
• Wire alignment: ensure the welding wire is properly aligned and centred in the joint. Misalignment can lead to irregular weld beads and poor penetration.
• Preheat for thick materials: preheat the workpiece, especially for thicker materials, to reduce the risk of hydrogen-induced cracking and improve weldability. View our range of heating equipment.

The cost of a submerged arc welding machine depends on the type of system and configuration required.

Standalone power sources or welding tractors are typically less expensive, while complete systems with column & boom manipulators or automated welding lines involve a higher investment.

Used and refurbished submerged arc welding equipment can significantly reduce upfront costs, particularly for businesses looking to increase capacity without investing in new automated systems.

Choosing the right setup is usually a balance between material thickness, weld length, and how automated your process needs to be.

For example:

• Welding tractors are commonly used for long, straight welds on large plates or beams.
• Column & boom systems are typically used for pressure vessels, tanks, and cylindrical fabrications.
• High-output power sources (800–1500A) are required for thicker materials and high-deposition welding.

Additional equipment, such as flux recovery systems, manipulators, and automated welding lines, may also be used depending on the application.

If you’re unsure which configuration is best for your workshop, our team can help recommend suitable submerged arc welding equipment from our current stock; get in touch.

Submerged arc welding is typically used for automated welding of thick steel sections, while MIG welding is more commonly used for manual or semi-automatic welding of thinner materials.

Submerged arc welding provides higher deposition rates and deeper penetration, making it ideal for heavy fabrication.