Page 84 - CITS - Fitter - Trade Theory

FITTER - CITS

5 Thin and Thick Metal Fabrication Work:
Gas Metal Arc Welding (GMAW/MIG), Gas Tungsten Arc Welding (GTAW/TIG), and Flux-Cored Arc Welding
(FCAW) are versatile processes suitable for both thin and thick metal fabrication.

6 Welding of Thick-Walled Large Diameter Pipes, Pressure Vessels, Storage Tanks, Ships:
Submerged Arc Welding (SAW) and Flux-Cored Arc Welding (FCAW) are preferred for their high deposition
rates, deep penetration capabilities, and suitability for welding thick materials.

7 Rail Welding:
Thermite Welding is commonly used for welding railroad tracks due to its ability to produce high-strength welds
in situ without the need for electricity.
8 Shipbuilding, Pressure Vessel Fabrication Work:

Submerged Arc Welding (SAW) and Gas Metal Arc Welding (GMAW/MIG) are commonly used for their high
productivity and ability to weld thick materials in various positions.
9 Thicker Pipe, Camshaft, Cutting Tools:

Gas Tungsten Arc Welding (GTAW/TIG) and Shielded Metal Arc Welding (SMAW/ Stick Welding) are preferred
for their ability to produce high-quality welds on thicker material.
10 Highly Reactive Material Welding Aerospace:

Electron Beam Welding (EBW) and Laser Beam Welding (LBW) are preferred for their ability to weld highly
reactive materials with precision in a controlled environment.

Different Types Of Arc Welding Machine

• Introduction Of an ARC Welding Machine:
An arc welding machine is a device used to create an electric arc between an electrode and the workpiece to
generate the intense heat required for welding. This heat melts the base metal and the filler material (if used),
creating a strong bond between the pieces being joined. Arc welding machines come in various types, such as
stick welding, MIG welding, TIG welding, and others, each tailored for specific welding applications and materials.
These machines are vital tools in fabrication, construction, manufacturing, and repair industries, offering versatility,
efficiency, and precision in joining metal components.
• Necessity Of an ARC Welding Machine:
The necessity of an arc welding machine is evident in its ability to fulfil several crucial functions and meet
various requirements essential for arc welding processes. Here’s why an arc welding machine is indispensable:
1 AC or DC Welding Supply: Arc welding machines provide either AC (Alternating Current) or DC (Direct
Current) welding supply, allowing flexibility to weld different types of materials and accommodate various
welding techniques.
2 Higher Voltage for Arc Striking: Arc welding machines deliver a higher Open Circuit Voltage (OCV) to initiate
the arc, providing the necessary energy for arc formation and ignition.
3 Lower Voltage for Arc Maintenance: After striking the arc, the machine adjusts the voltage to a lower level
(Arc Voltage - AV), ensuring a stable arc and consistent welding performance.
4 Voltage Conversion: Arc welding machines are equipped with transformers or rectifiers to convert the high
voltage from the main power supply (AC) into a lower voltage suitable for welding operations. In the case of
DC welding, rectification converts AC to DC.
5 Relationship between Arc Voltage and Welding Current: Arc welding machines establish a direct
relationship between Arc Voltage and Welding Current, ensuring proper arc stability, penetration, and control
during the welding process.
6 Control and Adjustment of Welding Current: The welding machine allows operators to control and adjust the
welding current as needed, ensuring optimal performance and weld quality for different welding applications
and materials.

69

CITS : CG & M - Fitter - Lesson 12 CITS : CG & M - Fitter - Lesson 12