The submerged arc welding (SAW), the welding are shielded by thick layer of granular flux fed into weld that cover the weld zone. The prevents spatter, sparks and radiation are other arc welding process.
The granular flux composite of silica, manganese oxide, lime and calcium fluoride. It flux is introduced to weld joint slightly ahead of arc by gravity from hopper. The granular flux is covered to arc shielding.
The flux are slightly arc is melted and mixed with molten metal to remove impurities and solidify on top of weld joint to form a glass like slag. When the weld area, the slag and infused flux granules are provide in top with good protection from atmosphere and then good thermal insulate permit deeper heat penetration. This result slowly cooling and give high quality welds joint. The recovered after welding process treated and reuse together.
In this process require a continuous fed consumable solid electrode and use a continuous bare wire electrode. The electrode wire is automatically fed from coil to arc.
Now the power source switched on and electrode touch on the work piece or placed some steel wool between electrode and work piece, so arc is struck and continuously under flux. The flux is melted and become conductive, provide electric current path between electrode and work piece.
The weld balking strips are providing for make butt welds. Thus strips are placed underside of weld joint, require for butt weld in material. If need faster speed of welding, thicker section steels are possibility. It provides high welding productivity and 4-10 time as shielded than metal arc welding.
Advantages of submerged arc welding:
- High disposition rate 45 kg/h possible
- No arc flash
- High speed welding, suitable for steel sheet at over 2.5 m/min
- Sound weld are readily made
- Deep weld penetration.
Limitation of submerged arc welding:
- Limited for ferrous metal
- Flux and slag residue can present health and safety issue.
- Require post weld slag removal and inter pass.
- It requires flux handling system.
Application of submerged arc welding:
- Stainless steel
- Nickel- base alloy
- Low alloy steel
- Carbon steel
- chromium molybdenum steels