By Rick Geiger
Most people know that welding is the process of fusing two pieces of metal into one. But they may not know just how prevalent it is in our modern society. According to Howard B. Cary in his book Modern Welding Technology, “Nearly everything we use daily is welded or made by equipment that is welded.” Which is why it's is such a useful skill to have. Whether you’re interested in welding as a career or hobby, your first step is to choose the type of welding you want to learn. According to WelderStation.com, there are more than 30 different kinds of welding the most common and of which is MIG welding. It’s also the most common for beginners. In fact, most people can learn to run a good bead with a MIG welder in just a few hours.
MIG stands for Metal Inert Gas. It’s also called Gas Metal Arc Welding (GMAW). But to understand the MIG welding process, let’s break it down:
MIG welding (along with TIG and Stick) is a type of arc welding. Simply put, arc welders use electricity to melt and bind metals together. An electric arc (thus the name) from an AC or DC power supply heats the metal to around 6500°F. When the metal cools back down, the separate pieces fuse together into one.
As the metal is super-heated, a continuous metal wire electrode is fed through the welding gun into a pool of liquid metal. This wire comes in different sizes and materials depending on the type of weld being performed.
MIG welding gets its name from the gas that is released from an attached tank. Because the metals react chemically to oxygen and nitrogen in the air when heated, the gas or slag is necessary to minimize the contact of the molten metal with the air. The gas forms a barrier to protect the weld from contaminants in the air.
Advantages & Disadvantages
The advantages of MIG welding over TIG and other techniques are:
- High-quality welds can be produced much faster
- Since a flux is not used, there is no chance for the entrapment of slag in the weld metal resulting in high-quality welds
- The gas shield protects the arc so that there is very little loss of alloying elements. Only minor weld spatter is produced
- A MIG welder is versatile and can be used with a wide variety of metals and alloys
- The MIG process can be operated in several ways, including semi and fully automatic
- A MIG welder cannot be used in the vertical or overhead positions because of the high heat input and the fluidity of the weld puddle
- The equipment is complex.
MillerWelding.com has a very thorough how-to on the MIG process that is well worth your time if you are interested in learning more.
Automation Personnel Services regularly has several MIG welder jobs available. Search our Job Board for open MIG welder positions and other jobs.