Tungsten Inert Gas (TIG) welding is a precision welding process used extensively in various industries to create high-quality, strong, and aesthetically pleasing welds. Unlike other welding methods, TIG welding uses a non-consumable tungsten electrode to produce the weld. This protects the welding area from contamination by an inert shielding gas, typically argon or helium. This technique known for producing clean, high-quality welds with superior control over the welding process. It ideal for joining thin sections of aluminum, stainless steel, magnesium, and other non-ferrous metals.
This distinctive guide aims to provide a comprehensive overview of TIG welding, exploring its definition, the detailed process, and the materials best suited for this method.
What Is a Tig Welder?
A TIG welder a specialized piece of equipment used in the Tungsten Inert Gas (TIG) welding process. This welding technique utilizes a non-consumable tungsten electrode to create the weld. The TIG welder comprises several key components, including a power supply, a TIG torch, a tungsten electrode, a shielding gas supply, and sometimes a filler metal.
The power supply generates the electric arc necessary to heat and melt the metal, with the capability to use either alternating current (AC) or direct current (DC), depending on the material being welded. AC is usually used for aluminum and magnesium, while DC is preferred for steel and other metals. The TIG torch holds the electrode and directs the shielding gas to the weld area. It is designed to offer precise control of the weld, and in many cases, it water-cooled to prevent overheating during prolonged use.
The tungsten electrode, with its exceptionally high melting point, maintains its shape and integrity while providing a stable arc essential for the welding process. The shielding gas, usually argon or helium, is supplied through the torch to protect the weld area from atmospheric contamination, thereby preventing oxidation and other impurities from compromising the weld quality.
Components of a Tig Welder
Here are the components of a TIG welder:
Power Supply
The power supply is the heart of the TIG welder. It provides the required electrical current to create the arc between the workpiece and tungsten electrode. TIG welders can operate on either alternating current (AC) or direct current (DC), depending on the material being welded. AC is usually used for welding aluminum and magnesium, while DC is used for steel, stainless steel, and other metals. The power supply allows for precise control of the welding current and voltage, which is crucial for producing high-quality welds.
TIG Torch
The TIG torch is a handheld device that houses the tungsten electrode and delivers the shielding gas to the weld area. The torch design enables the welder to manipulate the electrode with precision and control. It often includes a cooling mechanism, either air-cooled for lighter applications or water-cooled for more demanding tasks. The TIG welding torch parts also features a ceramic nozzle that focuses on shielding gas flow and protecting the electrode.
Tungsten Electrode
The tungsten electrode is a non-consumable rod made of tungsten or a tungsten alloy. Its high melting point allows it to maintain its shape and integrity while conducting the welding arc. Depending on the specific requirements of the job, the electrode can be sharpened to a fine point for DC welding or rounded for AC welding. Tungsten electrodes come in various types, such as pure tungsten, thoriated, created, and lanthanide, each suitable for different materials and applications.
Shielding Gas Supply
The shielding gas, usually argon or a mixture of argon and helium, is supplied through the TIG torch to protect the weld area from atmospheric contamination. The gas creates an inert environment around the weld pool, preventing oxidation and other impurities that could weaken the weld. The gas flow rate could be adjusted to ensure optimal coverage and protection.
Filler Metal
In many TIG welding applications, a filler metal rod fed into the weld pool to add material and reinforce the weld. The filler metal used depends on the desired properties of the finished weld and the base materials welded. While TIG welding can be performed without filler metal (autogenous welding) on certain joints, using filler metal standard for creating strong, durable welds.
Foot Pedal or Hand Control
The foot pedal or hand control allows the welder to adjust the welding current in real time, providing precise control over the heat input. This feature is handy for delicate or intricate welding tasks, where fine adjustments are necessary to avoid overheating or burning through the material.
Ground Clamp
The ground clamp completes the electrical circuit between the welder TIG and the workpiece. It allows a stable and consistent flow of electricity, which is essential for maintaining a steady arc and producing a quality weld. The ground clamp must be secured to the workpiece or welding table to function properly.
Cooling System
For more demanding welding tasks, a cooling system is integrated into the TIG welder to prevent overheating of the torch and components. Water-cooled torches are common in industrial applications, where prolonged welding can generate significant heat. The cooling system circulates water or coolant through the torch, maintaining a manageable temperature and extending the equipment’s lifespan.
How to Tig Weld
TIG welding process
To start TIG welding, you first need to gather your equipment and safety gear. Essential items include a TIG welder, tungsten electrodes, filler rods, and an inert gas supply, typically argon. Safety is paramount, so ensure you have a welding helmet, gloves, apron, and safety glasses. Adequate ventilation or an exhaust system is also crucial to avoid inhaling harmful fumes.
Next, prepare the workpiece by cleaning it thoroughly. Using a wire brush, grinder, or chemical cleaner, remove any rust, oil, paint, or other contaminants. Proper preparation is vital for achieving a clean, strong weld. Position the pieces to be welded and secure them with clamps or fixtures to ensure stability during welding.
Set up the TIG welder by adjusting the power settings to the appropriate amperage based on the thickness and type of material. Set the argon flow rate, typically between 15-20 cubic feet per hour (CFH). Prepare the tungsten electrode by sharpening it to a point for precise control, especially for DC welding. For AC welding, commonly used for aluminum, a balled tip might be preferred.
Position the tungsten electrode correctly, ensuring it extends about 1/4 inch from the gas nozzle. Hold the torch at 15-20 degree angle from vertical, pointing in the direction of travel. To initiate the arc, use a foot pedal or torch switch. For scratch start or lift start techniques, touch the tungsten to the workpiece and then lift it slightly to initiate the arc. Once the arc is started, a small molten weld pool will form at the base material.
Add the filler rod into the leading edge of the weld pool, feeding it steadily. To prevent contamination, avoid touching the tungsten with the filler rod. Maintain a consistent arc length, keeping a steady hand and a distance of about 1/8 inch between the tungsten and the workpiece. Control the weld pool by adjusting your travel speed and using the foot pedal to modulate the amperage. This allows you to control the size and penetration of the weld pool.
As you complete the weld, gradually reduce the current to taper off the arc. This helps fill the crater at the end of the weld and prevents cracking. Allow the shielding gas to flow for a few seconds after stopping the arc to protect the weld as it cools. Finally, inspect the weld visually for a smooth, even bead with no cracks, porosity, or other defects. Clean up any slag or oxide buildup from the weld area.
Difference Between a Mig Welder and a Tig Welder
TIG welder
Here is a table and a brief note to explain the differences between MIG welder and TIG welder:
| Feature | MIG Welding | TIG Welding |
| Electrode Type | Consumable solid wire | Non-consumable tungsten electrode (separate filler rod needed) |
| Shielding Gas | Mixture of Argon and CO2 (or other) | Pure Argon or Helium |
| Process | Arc welding with continuously fed electrode | Arc welding with separate filler rod manipulated by hand |
| Material Thickness | Good for thicker materials | Better for thinner materials |
| Cost | Generally lower initial cost | Generally higher initial cost |
Welding Process
MIG welding involves feeding a continuous consumable wire electrode through a welding gun. The wire melts and links with the base material to form the weld. An inert gas, typically argon or a mix of carbon dioxide and argon, shields the weld pool from atmospheric contamination.
However, TIG welding employs a non-consumable tungsten electrode to produce the weld. The welder may manually add filler metal by feeding a separate rod into the weld pool. An inert gas, usually argon or helium, protects the weld area from contamination.
Ease of Use
MIG welders are generally easier to learn and use, making them suitable for beginners and less experienced metal sheet welders. The continuous wire feed allows for a more straightforward and faster welding process, which is beneficial for larger projects and production work.
TIG welding needs a higher level of skill and precision. The process is slower and more intricate, involving manual control of the filler rod and the TIG welding torch components. TIG welding is ideal for experienced welders who need to make precise, high-quality welds.
Control and Precision
MIG welding offers less control over the welding process compared to TIG welding. It is well-suited for welding thicker materials and for applications where speed is a priority. However, it may not produce as clean or aesthetically pleasing welds as TIG welding.
TIG welder provides excellent control over the welding process, allowing for precise adjustments to the arc length, heat input, and filler material. This makes it wonderful for welding thin materials and for projects requiring high-quality, visually appealing welds.
Materials
MIG welding is popular and can be used on several materials, including steel, stainless steel, and aluminum. It is particularly effective for thicker materials and is commonly used in automotive and industrial uses
TIG welding is also versatile but excels in welding thin sections of non-ferrous metals such as aluminum, magnesium, and copper alloys. It is commonly used in aerospace, art metalwork, and applications where weld quality and appearance are critical.
Shielding Gas
The shielding gas for MIG welding often includes argon mixed with carbon dioxide or oxygen, depending on the material and desired weld properties. The choice of gas can affect the weld quality and spatter levels.
TIG welding typically uses pure argon or helium as the shielding gas. Argon is the most common choice due to its effectiveness in protecting the weld pool and providing a stable arc.
Cost
MIG welding equipment and consumables are generally less expensive than those for TIG welding. The lower cost and ease of use make MIG welding a cost-effective option for many applications. However, TIG welding equipment can be more expensive, and the process is more time-consuming, leading to higher labour costs. However, the investment justified for projects requiring the highest quality and precision.
Common Materials for Tig Welder
Aluminum TIG welding
Here some of the most common materials used in TIG welding:
Aluminum
Aluminum is a popular choice for TIG welding because of its high corrosion resistance and lightweight nature. However, welding aluminum can be difficult hallenging because of its high thermal conductivity and the presence of an oxide layer with a higher melting point than the base metal. To TIG weld aluminum effectively, welders typically use alternating current (AC) to break up the oxide layer and achieve good penetration.
Stainless Steel
Stainless steel commonly used in industries that require strong, durable, and corrosion-resistant welds. TIG welding is ideal for stainless steel because it allows for precise heat control, minimizing the risk of distortion and oxidation. Direct current (DC) with a negative electrode commonly used for TIG welding stainless steel, along with a ceriated or thoriated tungsten electrode.
Copper
Copper and its alloys are good conductors of electricity and heat, making them useful in electrical and heat exchange applications. TIG welding copper can be challenging due to its high thermal conductivity, which requires higher heat input to achieve proper fusion. Direct current (DC) used with a thoriated tungsten electrode, and pure argon or a mix of argon and helium the preferred shielding gas. Preheating the workpiece helps achieve better weld penetration and reduces the risk of cracking.
Conclusion
TIG welding is a versatile and highly precise process essential for joining various metals, including aluminum, stainless steel, and copper alloys. Understanding the fundamentals of TIG welding, from its definition and process to the materials involved, is crucial for producing high-quality welds. With the right equipment, meticulous preparation, and practiced technique, TIG welding offers unmatched control and finesse, making it an invaluable skill in the field of metal fabrication and repair.
