What is Metal Inert Gas (MIG) Welding Process : Introduction, Working Principle, Equipment's of MIG, Advantages, Dis-Advantages, Application

Introduction:-

Metal Inert Gas (MIG) welding definition:-

It is a welding interaction wherein an electric curve structures between a consumable wire anode and the workpiece. This cycle utilizes idle gases or gas blends as the safeguarding gas. Argon and helium are normally utilized for the MIG welding of non-ferrous metals like aluminum.

Gas Metal Arc Welding (GMAW) is an arc fusion process that joins metals. It does this by warming the metals with an electric bend the curve is between a constant, consumable cathode wire and the workpiece. They are protected from impurities in the environment by a safeguarding gas.

 

Working:-

Parallel to MIG welding, TIG welding is conducted using inert gases.

The arc is drawn between the melting wire conductor and therefore the work.

The current to the positively poled wire is provided through a contact nozzle (tip). Here it is practicable to work with high current densities (> 100 A/mm²)

In comparison, the potential current densities used for TIG welding with AC lie around 20 to 30 A/mm²

The melting power of MIG welding is therefore considered high with the TIG process.

Contact nozzle and therefore the comparatively short wire end are enclosed by noble gas.

This gas serves to safeguard the melt pool, wire, and arc in addition on cool the contact nozzle.

The filler wire from 0.8 to 2.0 mm diameter is carried as rolls and fed to the welding zone with the cooperation of wire feed rolls.

 

Major Equipment's of MIG:-

The major equipment's of MIG is as follows:

• Power supply

• Welding control and wire feed motor

• Welding gun

• Welding wire

• Shielded gas

• Power Supply: Most GMAW welding is completed with DC (DC) reverse polarity. The primary source is normally either 230 V or 460 V AC current input powers, which is changed by a rectifier unit to secondary circuit DC The power source should be a constant voltage welding machine (CV). This contrasts with SMAW welding that uses constant current (CC) power supplies.
• Welding control and wire feed motor: For MIG machines with constant voltage, current (amperage) is controlled by wire feed speed. Wire feed speed (WFS) refers to the speed at which the extended electrode wire is fed out of the gun into the weld bead. The speed is usually measured in meters per minute. If wire speed is increased, tamper age is also increased and inverse the same.
• Welding Gun: As compared to a TIG electrode holder, the MIG gun is more expensive and complex. This is often a result of there's a lot of need for it than simply carrying electric power to the conductor wire.

A weld power line cable connection brings electrical energy to the gun's contact tube area. The weapon(Gun) guides protecting gas into the weld zone.

The gun has conjointly a affiliation for obtaining the conductor wire from a drive rolls, to the contact tube inside the gas nozzle.

A trigger switch association permits to control weld beginning and ending.

• Electrode Wire: Contrasted with different anodes, for example, those utilized for SMAW, the cathode wire for GMAW is little in size. Also, the current utilized for GMAW wires can be very high.

• Shielded Gas: Shielding gases for semiautomatic MIG flow from the welding gun nozzle. They shield the melting conductor and weld zone from the encompassing atmosphere, which might contaminate the weld. choosing the right shielding gas will depend on the metal being welded, the weld quality or metal properties desired, method performance, and price of the gas.

 

Advantages of MIG:-

The advantages of  MIG welding are as follows:

• Higher welding speeds.

• Greater deposition rates.

• Less post welding cleaning (e g. no slag to chip off weld).

• Better weld pool visibility.

• No stub edge losses or wasted man-hours caused by changing electrodes.

• Unskilled labor required to operate M.I.G / M.A.G.S welding torch.

• Positional welding offers no issue when correlated to other processes.

• The process is easily automated.

• No fluxes required in most cases.

 

Disadvantages of MIG:-

The disadvantages of  MIG welding are as follows:

• Higher initial setup cost.

• The climate encompassing the welding interaction must be steady (thus the safeguarding gasses); subsequently, this cycle is restricted to sans draft conditions.

• Higher support costs because of extra electronic segments.

• The setting of plant variables needs a high ability level.

• Less capable where high duty cycle requirements are necessary.

• Radiation effects are more severe.

 

Applications of MIG:-

The applications of  MIG welding are as follows:

• MIG is best useful for the fabrication of sheets.

• Mostly all available metals can be weld.

• It can be used for deep groove welding.