Before going to Arc welding we first discuss welding So, Welding is defined as
It is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence.
This is often done by melting the workpiece and adding a filler material from a pool of molten material that cools to become a strong joint,
but sometimes the pressure is used in conjunction with heat, or by itself, to produce the weld.
This is in contrast with soldering and brazing which involves melting a lower-melting-point material between the workpiece to form a bond between them, without melting the workpiece.
Another definition is,
The welding process is a material joining process which produces coalescence of Material by heating them to suitable temperature with or without application of pressure or
by the application of pressure alone and with or without the use of filler materials.
Arc Welding Definition:
Arc welding is a welding process that is used to join metal to metal by using electricity to create enough heat to melt metal,
and the melted metals when the cool result in a binding of the metals.
Arc welding is one of several fusion processes for joining metals.
By applying intense heat, metal at the joint between two parts is melted and caused to intermix directly, or more commonly, with an intermediate molten filler metal.
Upon cooling and solidification, a metallurgical bond is created.
Since the joining is an intermixture of metals the final weldment potentially has the same strength properties as the metals of the parts.
A problem that arises in arc welding is the contamination of the metal with elements in the atmosphere (O, H, N, etc). There can also be a problem with the surface that is not clean.
The solution to this Includes,
- Gas shields: An inert gas is blown into the weld zone to drive away other atmospheric gases.
- Flux: A material that is added to clean the surface may also give off a gas to drive away unwanted gases.
Let’s understand by an Arc welding circuit or Working diagram:
Arc welding working or circuit diagram:
An AC or DC power sources, fitted with whatever controls may be needed, is connected by work cable to the workpiece and by an electrode cable to electrode holder of some type,
which makes electrical contact with the welding electrode.
An arc is created across the gap when the energized circuit and
The electrode tip touches the workpiece and is withdrawn yet still within close contact.
The arc produces a temperature of about 6500-degree centigrade at the tip.
This heat melts both the base metal and the electrode producing a pool of molten metal sometimes called a creator.
The creator solidifies behind the electrode as it is moved along the joint. This result is a fusion bond.
Arc Welding Types:
- Carbon Arc
- Flux-cored Arc
- Gas Metal-Arc
- Gas Tungsten Arc
- Plasma Arc
- Shielded Metal Arc
- Stub Arc
- Submerged Arc
- Atomic hydrogen
- Electroslag Welding (ESW)
- Electrogas Welding (EGW)
Arc Welding Parts or Basic Equipment:
From the Diagram Some equipment or parts used in the Arc welding process you can see and Some are not shown in the diagram which also I am going to explain. So,
The main parts are:
- Welding Machine (Power Supply)
- Hand Gloves
- Chipping Hammers
- Wire Brush
Welding Machine (Power Supply):
Electric or Power is supplying from Direct Board to Welding Machine to Electrode cable to Electrode Holder.
The main function is to deliver the current to the electrode holder from the machine.
The function is to hold the Electrode.
This electrode creates a spark when contacting the work.
While performing welding operation safety comes first so for the hand we use here Hand gloves.
As the welding operation temperature is too high we can see the operation with the naked eye but after some time the eye gets damaged.
The eye can not sustain with high temperature therefor here we use Goggles.
Aprons are like clothes. We wear this for safety purposes.
This instrument is for holding the workpiece whenever required.
To remove unwanted material from the welded workpiece that is slag we use a wire brush.
Arc Welding Temperature / Working:
The Arc welding temperature ranges from a minimum 3000-degree centigrade to up to 20000-degree centigrade.
So as the Diagram is shown above in which set up has been shown.
Now supplying the power from machine to the electrodes by the electrode cable and holder. So,
the workpiece is mounted there than before electrode touches the workpiece we have to maintain 2 to 3 mm gap because when you directly touch it,
It might get sticks and do vibrates.
Arc Welding Advantages, Disadvantages, and Application:
- The process gives high deposition rates.
- Welding speed is high.
- Wire consumption is low.
- The consumption of electrical energy is low, as a maximum of 97 % of heat energy can be utilized.
- Any length can be welded without any interruption.
- High-quality Welds are achieved with no fusion defects, no porosity and slag inclusions.
The main disadvantages are
- High skilled operator required to perform an operation.
- Arc is invisible, it can be controlled only by measuring arc voltage and current.
- It can be used only in the down hand welding position.
- The application of Arc welding in the various department like:
- Industries Construction
- Farm equipment
- Lawn and Garden
- Highway Equipment
- Institutional Equipment
- Railways Department
- and There are various other places there also this arc welding is used.
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