what is mig welding?
Metal Inert Gas (MIG) welding, also known as Gas Metal Arc Welding (GMAW), is a widely used arc welding process that offers versatility and high productivity for joining various types of metals. In MIG welding, a continuous solid wire electrode is fed through a welding gun and into the weld pool, where it melts and fuses the base materials together. This process is commonly used in industries such as automotive, construction, and manufacturing due to its efficiency and effectiveness in creating strong weld joints.
The history of MIG welding dates back to 1949 when it was first patented in the USA for welding aluminum. Initially, helium gas was used as a shielding gas to protect the arc and weld pool. However, in the early 1950s, the process gained popularity in the UK for welding aluminum with argon as the shielding gas and for welding carbon steels using CO2. The use of CO2 and argon-CO2 mixtures in the process led to the development of metal active gas (MAG) welding processes. MIG welding quickly became an attractive alternative to Manual Metal Arc (MMA) welding due to its high deposition rates and productivity.
MIG welding is a versatile technique that can be used for welding both thin sheets and thick sections of metal. The process involves striking an arc between the wire electrode and the workpiece, melting them to form a weld pool. The wire electrode acts as both a heat source, through the arc at the wire tip, and a filler metal for the welding joint. A shielding gas, selected based on the material being welded, is fed through a nozzle surrounding the wire to protect the weld pool from atmospheric contaminants. The wire is continuously fed from a reel by a motor drive, while the welder moves the welding torch along the joint line to create the weld.
The process characteristics of MIG welding make it suitable for various applications. The wire diameter and feed speed determine the welding current, as the burn-off rate of the wire balances with the feed speed. The process can be manual, semi-automatic, or fully automatic, depending on the level of control required during welding. Manual MIG welding involves manual control of travel speed and wire position, while mechanized welding may require some manual adjustments during the process.
One of the key aspects of MIG welding is the metal transfer mode, which determines the operating features of the process. There are three principal metal transfer modes: short-circuiting or dip transfer, droplet or spray transfer, and pulsed transfer. Short-circuiting and pulsed transfer are used for low current operations, while spray transfer is employed with high welding currents.
In conclusion, MIG welding is a versatile and efficient welding process that offers high productivity and strong weld joints. With its ability to weld a wide range of materials and thicknesses, MIG welding continues to be a popular choice in various industries for joining metal components.