Short Answer:

TIG welding, also called Tungsten Inert Gas welding, is a process that uses a non-consumable tungsten electrode to produce a weld. The heat generated by the arc between the tungsten electrode and the workpiece melts the base metal and forms a weld joint. An inert gas like argon or helium is used to protect the weld from oxidation.

TIG welding provides very clean, strong, and precise welds. It is suitable for welding thin materials and non-ferrous metals like aluminum, magnesium, and copper alloys. The process requires high skill but gives excellent control over the welding operation and weld quality.

Detailed Explanation :

TIG Welding

TIG welding stands for Tungsten Inert Gas welding, also known as Gas Tungsten Arc Welding (GTAW). In this welding process, a non-consumable tungsten electrode is used to produce the arc that generates the heat necessary to melt the base metal. An inert shielding gas, such as argon or helium, is supplied around the welding area to protect the molten weld pool from atmospheric contamination. TIG welding is known for its precision, cleanliness, and high-quality welds, making it widely used in industries that require accuracy and strength in joining metals.

1. Principle of TIG Welding:
   The basic principle of TIG welding is the creation of an electric arc between a non-consumable tungsten electrode and the workpiece. The arc generates intense heat that melts the metal at the joint, forming a weld pool. If required, a separate filler rod may be manually added into the weld pool to strengthen the joint. The shielding gas, which flows through the torch, protects the weld zone from oxygen, nitrogen, and other contaminants that could weaken the weld.

The tungsten electrode is chosen because it has a very high melting point (around 3400°C) and can withstand the heat of the arc without melting, allowing precise control during the welding process.

2. Equipment Used in TIG Welding:
   A TIG welding setup consists of several essential components, including:

• Power Source: Supplies a constant current, either direct current (DC) or alternating current (AC), depending on the metal type.
• Welding Torch: Holds the tungsten electrode and directs the shielding gas around the weld area.
• Tungsten Electrode: Non-consumable electrode that conducts current and generates the arc.
• Shielding Gas Supply: Generally argon, helium, or a mixture of both, used to protect the molten metal from oxidation.
• Filler Rod (Optional): Added separately to fill gaps and strengthen the weld joint.
• Ground Clamp: Completes the electrical circuit.

3. Working Process of TIG Welding:
   When the welder presses the switch on the TIG torch, the electric current starts flowing through the tungsten electrode. The welder maintains a small gap between the electrode tip and the workpiece surface. This gap allows the formation of an electric arc that melts the base metal.

As the molten pool forms, the shielding gas flows continuously to cover the area and prevent contamination. The welder manually adds filler metal (if needed) into the molten pool to form a stronger weld. The torch and filler rod are moved steadily along the joint to create a smooth and uniform weld bead.

TIG welding can be performed using either DC (Direct Current) or AC (Alternating Current):

• DCEN (Direct Current Electrode Negative): Commonly used for steel, stainless steel, and copper.
• AC (Alternating Current): Used for aluminum and magnesium to clean oxide layers while welding.

4. Features and Characteristics of TIG Welding:

• Uses a non-consumable tungsten electrode.
• Can be used with or without filler material.
• Provides excellent control over heat input and weld bead.
• Produces very clean and precise welds with no slag.
• Suitable for thin materials and critical joints.
• Works well with both ferrous and non-ferrous metals.

5. Advantages of TIG Welding:

• Produces high-quality, clean, and precise welds.
• Ideal for thin materials and delicate parts.
• No flux or slag formation, hence minimal cleaning required.
• Good control over welding heat and filler addition.
• Can be used for almost all metals, including stainless steel, aluminum, and copper.

6. Disadvantages of TIG Welding:

• Welding speed is slower compared to other methods like MIG.
• Requires high skill and steady hand control.
• Equipment setup is more complex and costly.
• Not suitable for outdoor welding due to gas interference by wind.
• Inefficient for thicker materials because of low deposition rate.

7. Applications of TIG Welding:
   TIG welding is commonly used in industries where precision and appearance are important.
   Some major applications include:

• Aerospace and aircraft manufacturing.
• Welding of thin sheets in the automotive industry.
• Fabrication of food and chemical processing equipment.
• Welding of stainless steel pipelines and pressure vessels.
• Repairing molds, tools, and dies.
• Joining non-ferrous metals such as aluminum, copper, and magnesium alloys.

8. Difference Between TIG and MIG Welding:
   Although both are gas-shielded processes, TIG welding differs from MIG welding in several ways. MIG uses a consumable wire electrode and is faster, while TIG uses a non-consumable tungsten electrode and gives better precision. TIG welding requires higher skill but produces finer quality welds, whereas MIG is more suitable for mass production and thicker materials.

Conclusion:

TIG welding is one of the most advanced and precise welding techniques used in modern manufacturing and fabrication. Its ability to produce clean, high-quality, and strong welds makes it ideal for applications requiring accuracy and aesthetic finish. Although the process demands high operator skill and is slower than other welding methods, its versatility and superior weld quality make TIG welding an essential process in aerospace, automotive, and industrial production.