WHAT IS THE TIG OR ARGON PROCESS CALLED?

The acronym TIG stands for “Tungsten Inert Gas,” referring to a welding process carried out in an inert gas shielding atmosphere using a tungsten electrode. This process involves establishing an arc between a theoretically non-consumable tungsten electrode and the workpiece, and can be performed with or without filler material. When filler is used, it is supplied separately, either manually or automatically. The choice of filler material in TIG welding depends on the type of base material, its thickness, the welding position, the energy required at the arc, the desired quality, and the cost of the weld. Due to their inert properties, argon or helium can be used in nearly all TIG welding applications. However, for thin materials, argon is recommended. In practice, helium is only used on materials with high thermal conductivity, such as copper and aluminum.

What do we mean by TIG welding?

The high arc voltage of helium makes it effective for welding heavy thicknesses that require greater heat input and penetration.

Argon-helium mixtures improve weld quality and are used primarily for welding aluminum and copper in heavy thicknesses, unalloyed carbon steels, austenitic stainless steels, and especially in automated welding, where high travel speeds can be achieved. Adding hydrogen to argon increases the arc voltage and produces a more concentrated arc, allowing for greater heat input and a narrower weld bead. Argon-hydrogen mixtures are used mainly for welding austenitic stainless steel and nickel-based alloys. Typical mixture percentages range from 1 to 10% hydrogen; due to the metallurgical effects of hydrogen on the molten metal, these mixtures cannot be used for welding carbon steels, aluminum, copper, or titanium.

Field of application.

The TIG welding process can be used for:

• Joints requiring high weld quality.
• Welding of metals highly susceptible to oxidation, such as titanium and aluminum.
• All weldable materials, except zinc. Its greatest use is in heat-resistant steels, stainless steels, and aluminum.
• Root passes on heavy-wall piping, since subsequent passes can be completed using MIG-MAG.
• Food processing, aeronautical, and aerospace industries. Fabrication of products for the chemical and power generation industries.

Advantages and disadvantages.

The main advantages of the TIG process are as follows:

• Stable and concentrated arc.
• Suitable for use in all positions and on all joint types.
• Good bead appearance with smooth, clean finished surfaces.
• No spatter or slag, eliminating the need for post-weld cleanup.
• Applicable to thin materials (from 0.3 mm).
• Can be used with or without filler material.

Limitations include:

• It is a relatively low-productivity process, particularly for joints in materials thicker than 4 mm.
• There are limitations on its use in outdoor environments.
• It requires a skilled welder to perform.