TIG welding offers excellent control over the welding arc, heat input, and weld appearance. Depending on the material, thickness, and application, modern TIG welders may provide different welding modes to meet different requirements.

1 TIG DC — Standard DC TIG Welding

TIG DC is one of the most common TIG welding modes. It uses direct current and is widely used for materials such as: Stainless steel, Carbon steel, Mild steel, Copper, Titanium and other metals

DC TIG provides a stable arc and precise heat control, making it suitable for both general fabrication and precision welding.

Best for:stainless steel, carbon steel, thin and medium-thickness metal.

TIG DC = Stable arc + Precise control + Versatile applications

2 TIG AC — TIG Welding for Aluminum

TIG AC uses alternating current and is mainly designed for welding aluminum and aluminum alloys.

During AC welding, the current alternates between different polarities. This helps break through the oxide layer on aluminum while maintaining effective penetration.

Many advanced AC TIG welders also allow users to adjust:

AC Frequency – controls arc characteristics and arc focus

AC Balance – controls the balance between cleaning action and penetration

AC Waveform – adjusts the shape and characteristics of the AC output

Best for: aluminum and aluminum alloys.

TIG AC = Aluminum welding + Oxide cleaning + Excellent arc control

3 TIG Pulse — Better Heat Control

TIG Pulse alternates between a higher peak current and a lower base current at a set frequency.

This allows the welder to control the average heat input more effectively while maintaining arc stability.

Typical pulse parameters include: Peak Current, Base Current, Pulse Frequency, Pulse Duty Cycle

Pulse TIG is particularly useful for thin materials and applications where heat control and weld appearance are important. 

Best for: thin sheet metal, stainless steel, precision welding and applications requiring reduced heat input.

TIG Pulse = Controlled heat input + Better weld pool control + Reduced distortion

4 TIG Spot — Fast and Controlled Spot Welding

TIG Spot allows the user to set a specific welding time.

Once the torch trigger is activated, the machine produces welding current for the preset time and then automatically stops.

For example: Spot Time: 1.0 second 

The machine will automatically complete the welding cycle after approximately one second.

This is useful for: Tack welding, Thin sheet metal, Repetitive welding, Small components, Applications requiring consistent weld duration

TIG Spot = Fixed welding time + Repeatability + Easy operation

5 TIG Cold Welding — Ultra-Low Heat Input

TIG Cold Welding is designed to minimize heat input by using very short and controlled current pulses.

Despite its name, Cold Welding does not mean welding without heat. It refers to a welding process with significantly lower heat input compared with conventional TIG welding.

This can help reduce: Burn-through, Workpiece distortion, Heat-affected areas, Discoloration on thin stainless steel

It is particularly useful for very thin materials and precision applications.

Best for: thin stainless steel, decorative metalwork, precision welding and heat-sensitive components.

TIG Cold Welding = Short welding time + Low heat input + Less distortion

6 TIG Repeat / Interval Welding — Controlled Intermittent Welding

Some advanced TIG machines provide Repeat, Interval, or similar intermittent welding functions.

Instead of keeping the arc continuously on, the machine repeatedly switches between welding and non-welding periods according to preset parameters.

For example: Welding Time → Pause Time → Welding Time → Pause Time

This can help control overall heat input and is useful when making a series of repeated welds.

It can also be useful for applications where continuous welding would introduce excessive heat.

TIG Repeat = Repeated welding cycles + Better heat management + Consistent operation

How to Choose the Right TIG Mode?

Different TIG modes are designed for different welding requirements.

A Simple Way to Remember

General welding → TIG DC

Aluminum → TIG AC

Thin metal / heat control → TIG Pulse

Fixed-time spot welding → TIG Spot

Ultra-low heat input → TIG Cold Welding

Repeated intermittent welding → TIG Repeat / Interval

Important Note: Welding Modes vs. Trigger Modes

It is important to distinguish welding functions from torch trigger modes.

Welding functions determine how the welding current is generated and controlled, such as:

* DC

* AC

* Pulse

* Spot

* Cold Welding

* Repeat / Interval

While 2T and 4T mainly control how the torch trigger operates.

Therefore, 2T/4T should generally be described as Trigger Modes or Torch Control Modes, rather than independent TIG welding processes.