One of the most common welding techniques is the Submerged Arc Welding (SAW). It is important to note that this was one of the first types of welding to get a patent. To do this type of welding there needs to be an electrode that is either tubular or solid (consumable). This will need a continuous feed as well.
In order to protect the weld and the arc zone they are "submerged" to protect them from contamination from the atmosphere. Fusible flux that includes lime, silica, manganese oxide or calcium fluoride is used under a blanket. Other compounds can be used as well.
As it melts the flux acts as a conductor and creates a path for the current that moves between the electrode and the work that is being done. This creates a thicker layer of the flux and it covers the metal as it melts. By doing this process there is no spatter or sparks because the flux is covering everything. This process will also suppress any ultraviolet radiation or fumes that will from this Submerged Arc Welding (SAW) process.
Most welders will do this process in either an automatic or mechanized mode of operation but some of the other types of guns like the semi-automatic ones (that are hand held) can be used since they have a pressurized or a gravity type of flux feed . Usually you will have to use this in either the flat or horizontal fillet positions.
The SAW technique of welding uses a standard wire and it can also use some of the specialty forms. A good wire for this filler material will be between 1/16 and ¼ inches thick. Sometimes welders have used a wire that is twisted so the arc will begin to oscillate. Sometimes this will be helpful to fuse the bottom of the weld and the base metal together.
There are several advantages to using SAW which include:
-It Has a high deposition rate and it can penetrate the weld deeply.
-When You have designed a good process and you have control over what you are doing you can be sure that you get a strong weld.
-You Can actually do this with thin sheets of steel and they can be done at a higher speed.
-There Are very minimal fumes or arc lights which makes this a safer process.
-You Can do this indoors or outdoors.
-You Do not have a lot of distortion.
-You Do not get any spatter on the weld because the arc is always under the blanket of flux.
-As With any technique there are a few limitations with the SAW method that include:
-You Are limited to only a few positions that you can use this within.
-You Can only use steel, stainless steel or a few nickel based metals.
-The Flux handling systems can be more complex and difficult to use.
-Slag Is a problem in a couple of ways: you can get residue from it that may cause some issues with your health or with safety and it will require a complicated slag removal system.