Submerged Arc Welding (SAW)

Posted on August-08-2020

What is Submerged Arc Welding?

This arc welding process involves the formation of an arc between a continuously fed electrode and a workpiece. This creates a blanket of powdered flux, which helps protect the weld zone. During welding, the arc is submerged beneath the flux blanket and it is not usually visible. This type of weld is a well-established method and extremely versatile.

How does SAW work?

Submerged arc welding, often referred to as ‘SAW’, is normally limited to flat or horizontal-fillet welding positions.

4 Components of Submerged Arc Welding (SAW)

SAW has four common features: a welding head, flux hopper, flux and an electrode. The welding head feeds the flux and the filler metal to the welding joint; this is also where the electrode (e.g. the filler metal) gets energised.

The flux hopper is where the flux is stored and it controls the rate of flux deposition on the welding joint. The flux is the part in which the shields protect the molten weld from atmospheric contamination. This component also cleans the weld metal and can modify its chemical composition.

Lastly, the electrode, or SAW filler material, is a standard wire that can be twisted to give the arc an oscillating movement. This wire helps fuse the weld to the base metal, and its electrode composition is dependent on the material being welded. Generally, electrodes are copper coated; this is to prevent rusting and increase their electrical conductivity.

Advantages vs. Disadvantages of SAW

Pros

SAW has high deposition rates and high operating factors in mechanised applications
It allows for deep weld penetration
With good process design and control, sound welds are readily made
There is minimal welding fume or arc light emitted
It is suitable for both indoor and outdoor works
The arc is always covered under the blanket of flux, meaning there’s no chance of spattering of weld
Between 50% and 90% of the flux is recoverable, recycled and then reused

Cons

This weld is limited to steel, stainless steels and some nickel-based alloys
It is also restricted to set positions (1F, 1G and 2F), as well as limited to long straight seams, rotated pipes or vessels
The flux and slag residue can present a health and safety concern
It is also limited to high thickness materials
It also requires post-weld slag removal and inter-pass
For proper root penetration, it needs backing strips
The flux handling systems it uses can be relatively troublesome

Contact Arc Welding

If you’re looking to buy or hire welding equipment, or for repairs and calibrations, get in touch with our team here at Arc Welding Services. You can give us a call us on 0121 327 2249, or fill out our online contact form and someone will be in touch.

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