Welding is one of the most widely used manufacturing process in the industrial world. Welcome back to The Mechanical Post ! Today let’s see, what is GMAW or MIG welding starting with their full forms:
MIG – Metal Inert Gas welding.
GMAW – Gas Metal Arc Welding.
GMAW is a type of manufacturing process in which two workpieces are joined togther by the application of electric arc. This electric arc causes the wire electrode to melt and form a part of the weld. Upon solidification of the weld, the two workpieces are joined together.
Unlike TIG welding which uses a non-consumable tungsten electrode, MIG uses a consumable metal electrode for welding purposes.
What is meant by consumable electrode?
What is an electric arc?
An electric arc is a continuous stream of electrons flowing through a medium between two conductors of an electric circuit and accompanied by intense heat generation and radiation.
MIG or GMAW are one of the types of ” electric arc welding “. The electric arc welding is the most extensively used method of joining components of metallic parts using the heat produced due to electric arc.
Construction of MIG.
- control switch for controlling the gas flow and power supply,
- contact tip,
- power supply cable for producing the arc,
- gas nozzle for shielding gas,
- electrode conduit and liner
- gas hose.
|By Mysid, TTLightningRod.-Vectorized by Mysid on a JPEG by TTLightningRod.,|
The control switch, or trigger, when pressed by the technician, starts the wire feed, electric power, and the shielding gas flow, producing an electric arc.
Why are inert gases used in MIG or GMAW welding?
Working of the MIG welding.
|Nathaniel C. Sheetz (User:Spangineer) / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)
The electrode is made up of metallic alloy wire, called a MIG wire, whose alloy and size, is depends on the composition of the metal being welded, Depending on the base material being welded the diameters of the electrodes used in MIG or GMAW range from 0.7 to 2.4 mm (0.028 – 0.095 in). For heavy duty operations, the electrode size could be upto 4mm in diameter.
In GMAW the technician doesn’t need to maintain a precise arc length, as well as feeding filler metal at the weld site this eases the welding process. In GMAW the operator is required to guide the torch properly over the area being welded, and also maintain the torch’s gas nozzle to remove spatter buildup after regular time intervals.
Any type of welding process which uses Electric Arc can be hazardous if proper precautions are not taken. Technicians or operators must wear suitable protective gear to prevent any harm.
You might also like to read :
Advantages of MIG or GMAW welding :
In GMAW not having to constantly change electrodes as done in TIG or chip away slag, as well as not having to brush the weld repeatedly saves the operator lot of time. Thus he can complete more work in less time.
Easy to Learn
It is so simple thanks to the semi-automated processes that one can learn GMAW in a very short time.
Good quality Welds
MIG provides better weld pool visibility. And with better control offered by the auto-feed wire, GMAW makes it simple to produce a great looking weld.
Less slag produced
GMAW uses a shielding gas to protect the arc, thus there is very little loss of alloying elements as the metal transfers across the arc. This reduces the amount of slag produces.
MIG welding is very flexible as it can weld a wide variety of metals and alloys, while operating at a variety of ways, such as semi and fully automatic. This gives a lot of option to choose from.
Faster Welding Speed
Due to semi and fully automatic processes possible time taken is reduced significantly.
Disadvantages of MIG Welding :
High initial as well as maintainance cost
The machines used in GMAW are complex and are expensive. Also the replacement cost of the shielding gases, feed wire electrode and electricity costs come along with the already expensive price tag.
Not suitable for Outdoor Welding
GMAW isn’t portable and can’t be used outdoors as the wind could scatter away the shielding gas.
Cannot be used for Thick Metals
While MIG welding is good for thin metals, it does not deliver proper penetration for thicker steel that requires a solid weld.
Applications of GMAW :
- For welding pipe joints.
- In ship building process.
- For Welding railway tracks.
- For Welding in automobiles etc.
If you like this post, do let us know about it in the comments and share with friends and family with social links given below.