Which is Hotter MIG or TIG Welding

The heat generated during welding is a crucial factor as it can affect the process and result. High heat improves penetration and enhances fluidity. This makes it easy for the molten metal to mix and solidify. However, excessive welding temperature also has negative effects. Too much heat can introduce residual stresses and lead to different types of welding defects.

Is MIG hotter than TIG welding? The answer to this question is an undebatable yes. MIG welding has a higher heat input which affects the temperature of the welding area. This article will explain the factors affecting the temperature of MIG vs TIG weld and the reasons why you will find MIG welding hotter. 

What is MIG Welding 

Metal inert gas (MIG) welding is a semi-automatic process that uses electricity and consumable wire to join two or more parts together. MIG welding is fast and simple to operate. You don’t need to have special skills and years of experience to operate a MIG welder. During MIG welding, an electric arc forms between the wire electrode and the workpiece. This arc heats them to produce a weld pool. They mix and solidify into a single piece. 

In MIG welding, you do not need an extra filler material as the wire electrode acts as one. When welding, a shielding gas, usually CO2, is used to protect the weld pool from contamination. This ensures deep penetration and gives final welds that are strong and smooth. MIG welding is versatile and you can use it for many metal types including copper, aluminum, steel, and nickel alloys. 

Factors Affecting MIG Welding Temperature

The MIG welding process is hot and generates a high amount of heat. However, several factors interact with one another and affect MIG welding temperature. Some of these factors include 

Wire Feed Speed

The rate at which you feed the electrode into the weld zone determines the temperature of the welding operation. Based on the material type and thickness you are working with, it is important to balance the speed to avoid excessive heat input. Using a higher-than-required feed speed increases electrode deposition and raises the temperature. However, a lower feed rate decreases the weld pool’s temperature. 

Voltage

The voltage you use also plays a huge role in determining the welding temperature. Voltage directly influences the arc length and maintains it during welding. When you use a high voltage, this raises the arc energy and increases the temperature of the joint. On the other hand, lower voltages reduce the arc energy and the size of the weld pool. 

Gun Angle and Movement

You should properly position the welding gun at an angle that gives you access to the operation. The gun should be about 45 degrees to control the arc length. Furthermore, the gun movement has a direct relationship with the welding temperature. Slow and steady movement ensures proper heat distribution and prevents overheating. 

Shielding Gas Type

The shielding gas you are using is also important. When MIG welding, you can work with argon, CO2, helium, and argon/CO2 mix. Pure argon cools the electric arc more and generates less heat. On the other hand, helium and CO2 lead to greater heat input and deeper penetration. With argon/CO2 mix, you have a stable balance between the properties of argon and CO2. 

What is TIG Welding

TIG welding is an arc welding process that permanently joins two or more workpieces. It uses a non-consumable tungsten electrode that gets hot but doesn’t melt or become a part of the weld. Just like MIG welding, an electric arc forms between the base metal and the electrode. The arc heats up and joins the pieces of metal together. The final welds are aesthetically pleasing and may not need to be further finished. You have control over the heat input and can work on thin materials efficiently. 

Factors Affecting TIG Welding Temperature

The following are some factors that affect the temperature of a TIG welding operation.

Current Type and Intensity

In TIG welding, you can either use a direct or alternating current based on the project’s requirements. In DC, the current flows in only one direction and generates more heat on the workpiece. There is a balance in heat distribution with AC TIG welding. Furthermore, using a high current increases the arc energy and the process temperature. 

Arc Length

The length of the arc significantly affects the TIG welding temperature. The arc length and temperature have an inverse relationship. A longer arc length dissipates the heat over a large area which reduces the temperature of the joint. However, shorter length increases heat intensity and input. 

Shielding Gas Flow Rate

The most common type of shielding gas in TIG welding is argon, helium, and argon/helium mixture. They help create a protective environment during the welding operation. A decreased flow rate increases the welding temperature. On the other hand, you should expect a lower temperature when the flow rate is increased.

Material Type

The properties of the metal you are working with also determine the welding temperature. Metals with a high thermal conductivity such as aluminum and copper require a higher processing temperature. The melting point of the metal is important as well. Those with a lower melting point need a low welding temperature to achieve the desired outcome. 

MIG Vs TIG Weld: Which is Hotter?

When comparing MIG and TIG welding in terms of hotness and heat generation, MIG welding is hotter because of many reasons. 

Heat Input

The heat input in MIG welding is higher than that of TIG. MIG welding works with more voltage and amperage which increases the temperature of the weld pool and surrounding material. Furthermore, you continuously feed in the electrode which results in higher heat. In TIG welding, you apply less heat and have more precise control over the process. 

Arc Temperature

The arc temperatures of both processes differ. TIG welding arc temperature is usually between 4,000°C to 5,000°C. This is because the heat input is more focused and controlled. However, the arc temperature of MIG welding goes as high as 6,000°C in some instances.

Heat Affected Zone (HAZ)

The total area of the heat-affected zone determines how hot the welding area will be. MIG welding results in a higher HAZ and affects the surrounding material. The lower heat input in TIG welding results in a smaller HAZ. Hence, TIG welding has a less pronounced impact on the base material with lower atmospheric temperature.

Cooling Rate

The time it takes for a TIG weld to cool down differs from that of MIG welds. The joint and surrounding material in TIG welding has a faster cooling rate and does not overheat. On the other hand, MIG welding cools down slowly and steadily. This is because of the higher heat input and larger weld pool. 

Material Thickness

The material thickness plays a significant role in determining the welding temperature. MIG welding deals more with thicker metals that require more heat. Furthermore, it may be necessary to preheat thick metals before welding which further raises the temperature. With TIG welding, the metal materials are thinner and do not need a lot of heat. 

Table 1: MIG welding vs TIG welding in terms of hotness and heat generation.

Conclusion

The debate about the heat difference between welding TIG vs MIG is nothing new. MIG welding produces a hotter arc which affects the overall welding temperature. The reasons for this are not far-fetched.  MIG welding has a higher heat input and arc temperature. Additionally, the heat affected zone is more with a slower cooling rate. However, you should consider other factors such as the material properties, quality of the final weld, and cost before using any welding process. 

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