What are the 4 types of welding and what are they used for? (Part 2)
MIG – GAS METAL ARC WELDING (GMAW)
What is MIG welding?
MIG, also known as gas metal arc welding, is one of the simplest types of welding, and involves molten metal (typically aluminium or steel) being transferred to the weld area through a wire feeder, which either remains stationary during use and moves with the torch head in a mechanised system or moves back and forth over an arc length. The heat from this filler material melts both parts being joined together causing them to form into one piece of molten metal. This process can be very quick depending on the size of the joint gap that needs filling.
What are the 4 types of welding and what are they used for? (Part 2)
Advantages of MIG welding
➤ MIG welding is an economical welding process because the equipment and consumables are relatively inexpensive.
➤ It can be performed with a wide range of skill levels.
➤ The welds made by MIG have good strength properties that can make them suitable for a variety of applications- such as structural steel work.
Disadvantages of MIG welding
One of the disadvantages of MIG welding is that it can’t be used in all positions (vertical or overhead). In addition, the quality of the finished product can vary depending on how well you maintain your equipment.
What does a wire feeder do in metal arc welding (MIG)?
A wire feeder continuously moves the electrode holder along a predetermined path to keep it close enough for welding. The wire is fed through an opening in the front of the welder’s nozzle, where it protrudes from under a protective cap and exits at its tip.
FLUX-CORED ARC WELDING (FCAW)
What is FCAW
Flux-cored arc welding (FCAW) is a technique that has been around for over fifty years. The process, which involves the use of an electrode covered with flux, was developed in response to some disadvantages associated with stick electrodes and shielded metal arc welding methods such as poor joint penetration, high heat input and low deposition rates.
What are the 4 types of welding and what are they used for? (Part 2)
Advantages of FCAW over other welding processes
Some of the advantages of FCAW are that it produces a consistent weld quality even at higher currents; less chance of slag inclusion than other processes like gas tungsten arc welding; provides much more shielding against external contamination than MIG or TIG due to its “all-in-one” design.
Disadvantages of FCAW
One of the biggest drawbacks of flux-cored arc welding is that it produces a lot more weld spatter than other welding processes because the flux coating can burn off quickly and create excess slag on the weld surface. This makes cleanup much more difficult, which in turn wastes time and money. Another disadvantage is that higher heat input tends to mean less concentration on actually creating an even bead; instead, most people focus their attention on avoiding overheating while using this type of welding process.
Applications for FCAW
One of the most common applications for FCAW is in sheet metal fabrication because it’s easy and quick when working with thinner materials that require little filler material. FCAW is also commonly used in joining thin gauge metals together such as strips or sheeting which require less heat input than other methods like TIG would need.
Can FCAW be used to weld steel or aluminium?
Aluminium cannot be welded with FCAW, but steel can. FCAW generally only works well with carbon steel, copper, brass, aluminium-copper alloys, aluminium-brass alloys (sometimes known as Bronzes) and stainless steel alloys such as 304L so don’t try using it unless you’re absolutely sure which metal you are using.
What are the 4 types of welding and what are they used for? (Part 2)
There are a number of different welding processes that can be used to join materials together. The type of process will depend on the thickness and size of the material you need to weld as well as what kind of finish you want or are required by your industry standards. If you need a highly versatile welding process, that covers many materials and applications, then TIG would be your best bet.
