Submerged Arc Welding - an overview
Submerged arc welding or SAW is a commonly used welding process for thick steel sheets or long welds. There are four components to this process. The welding head is used to feed flux and filler metal to the area that is being worked on. With the help of the electrode, the filler metal gets energized too. The flux hopper stores and controls the flux.
The granulated flux is an extremely important part. It allows the metal to be cleaned and shields molten atmospheric contamination. The granulated flux can be fused, mixed or bonded materials. It is also mixed with different materials depending on what the project is. The electrode or filler metal is usually in the form of a wire. There are special forms as well. If, a wire of filler metal is twisted it will give the arc an oscillating movement. The types of material that can be added with the electrode is used for are nickel-based alloys, low alloy steel, carbon steel and stainless steel. Other options that can change jobs up are the wire feed speed, travel speed, arc voltage, current type, electrode stick-out and contact tip.
This type of arc welding starts with the flux feeding the filler metal onto the joint. Placing steel wool between the electrode and joint before starting, works just as well as lighting the electrode with a torch to start. Once molten, the flux goes from being an insulator to a conductor. The wasted flux material or slag is removed after the weld. The electrode has several speeds. Predetermined speed is a continuous feeder. Semi-automatic speed allows manual movement of the head. Automatic speed is good for stationary jobs. The arc can be shortened and lengthened manually.
Submerged Arc Welding
There are some pros and cons to all types of welding. Submerged arc welding process is a specific type weld. To start, the job will have higher deposition and high operating factors with mechanized jobs. Sound and deep penetration welds are made possible with the easy control. Thicker sheets of metal is typically used for these welds, but thin sheets can be done. Another pro is the lack of edge preparation needed and little fumes created. The work can be done outside or inside and the welds are uniform and corrosion-resistant. Even with a thick sheet, a single pass is possible. Finally, the arc is always covered to allow no chance of splatter. One great thing is that more than half of the flux can be reused.
When it comes to arc welding, there are a few specific cons. This is due to the fact that it is a very specific weld type. The first obvious con is that the only materials to work on are some types of steel and some nickel-based alloys. The equipment can only be in the position of 1F, 1G and 2F. It is also limited to rotated pipes, vessels or straight seams for welds. The flux can be a bit troublesome to set up and can cause health concerns. A huge con is the fact that only thick welds are workable. There are also requirements for slag removal before you start and backing strips for root penetration.