What is Carbon Arc Welding Process?
Carbon Arc Welding (CAW) is an old welding process in which the arc is produced between the carbon electrode and workpiece or between the two carbon electrodes by using low voltage and high ampere current.
There are two types of Carbon Arc Welding
Having said that, let’s discuss single carbon arc welding as well as twin carbon arc welding one by one in detail.
#1) Single carbon arc welding
What is single carbon arc welding process?
The single carbon arc welding process is a type of carbon arc welding process in which the arc is produced between the carbon electrode and the workpiece.
In single carbon arc welding process, the welding power source used is a direct current (DC current power source).
This process has various benefits in welding galvanized sheet metal because the heat concentration is very less which ultimately minimizes the distortion of the sheet metal.
The single-carbon torch used in the carbon arc welding process is designed in such a way that it can withstand the higher temperature of the electrodes.
The main disadvantage of using single carbon arc welding is that the small amount of carbon from the electrode may be added to the weld puddle which is a contamination to the weld.
But his contamination of carbon can be avoided by using twin carbon arc welding.
#2) Twin carbon arc welding
What is twin carbon arc welding process?
The twin carbon arc welding process is a type of carbon arc welding process in which the arc is produced between the two carbon electrodes.
The torch used in twin carbon arc welding is different from the other welding torches.
It has two arms which hold the two carbon electrodes at specific angles.
These carbon electrodes are operated by the welder during the welding operation. The welder varies the distance (or gap) between the tip of the two carbon electrodes during the ongoing welding process.
The welding power source used for twin carbon arc welding is the alternative current source (AC source).
During this process, the welder touches the tip of both the carbon electrodes for initiating the current flow, and then moves the electrodes apart to some gap.
Because of this, the arc is produced at the top of the electrodes which produces a high temperature that is enough to heat the weld surface and melt a filler rod.
The carbon electrodes are not consumed during the welding process, but they gradually erode. So these carbon electrodes must be replaced after their erosion.
The length of the electrodes is generally 6″ and has a diameter ranging from 3/16″ to ½”.
In twin carbon arc welding process, the arc temperature reaches up to 5000 °C and it emits bright light.
To protect the eyes from such extreme bright light, welding helmet must be worn. To protect the body from the ultraviolet rays from the arc, protective clothing is essential for the welded.
Important things to know about Carbon Arc Welding Process
Here are the few important things that you should know about the carbon arc welding process.
- The electrodes used in carbon arc welding are made up of Non-consumable graphite (carbon).
- CAW process is easily adoptable for automated welding of simple shapes which require higher weld deposition.
- The advantage of carbon arc welding process is that the temperature of the weld puddle can be controlled by varying the arc length.
- The disadvantage of carbon arc welding process is that it requires separate filler material to fill the weld groove.
- The heat source in CAW process is obtained from the arc itself.
- Carbon Arc Welding process is sometimes confused with Arc air gouging process. The arc air gouging process and CAW process are exactly opposite to each other. CAW is a metal joining process, while arc air gouging is a metal removal process.
- Arc-air process has a single carbon electrode and it is used for removing defective welds, gouging out cracks, etc.