TIG Welding VS. MIG Welding

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TIG Welding VS. MIG Welding

Welding is a process used to join materials, usually metals or thermoplastics, by causing fusion. It involves melting the workpieces and adding a filler material to form a stong joint.

What is Metal Inert Gas (MIG) Welding?

MIG stands for “metal inert gas,” and it’s also known as gas metal arc welding (GMAW). MIG welding machines generate a powerful electrical current that runs through a handheld torch. The torch supplies the welding gas and automatically feeds the MIG welding wire. This wire creates an electrical arc that melts the metal being joined and provides filler material to strengthen the joint. A ground clamp is attached to the workpiece to protect the welder from shocks.

Welding Gas

Not all MIG welders require a separate gas supply. With gasless MIG (or flux-core welding), the welding wire is coated with chemicals that form their own shield as the wire melts.

Weld Speed

Speed is an important factor when it comes to the question of TIG vs. MIG welding, and the latter is by far the faster of the two. A MIG welding machine feeds welding wire through the torch automatically, at a speed set by the user. Beginners can slow the wire to suit their skill level, while professionals can speed it up to maximize productivity.

One drawback of MIG welding is that it doesn’t produce such a neat weld, so extra time may be required to clean things up for painting or electroplating.

Weld Strength

Any properly formed weld is extremely strong. As an old adage says, the weld is actually stronger than the original metal. This is true of any good MIG weld, but care is required. Although MIG welding produces a comparatively large and easy-to-manage pool of molten metal, trying to weld too quickly can produce uneven penetration that leads to weaknesses.

What is Tungsten Inert Gas (GTAW or TIG) Welding?

Tungsten Inert Gas (TIG) welding, also known as Gas Tungsten Arc Welding (GTAW), is a welding process that uses a tungsten electrode to produce the weld. It involves creating an arc between the tungsten electrode and the workpiece while shielding the weld area with an inert gas, typically argon or helium. This process is known for its precision and ability to weld a wide range of metals, including stainless steel, aluminum, and titanium, producing high-quality, clean, and strong welds. TIG welding requires a high level of skill due to its manual nature and control over the filler material and arc.

Welding Gas

As with MIG welding, TIG welding requires gas to shield the weld from impurities. It also helps prevent the fixed TIG electrode from overheating. TIG welding gas is normally composed of argon or a mix of argon and helium (another inert gas). Argon and hydrogen are used when TIG welding stainless steel.

Argon and argon/helium shields are heavier than the argon/carbon dioxide mix commonly used with MIG welding, so it’s possible to TIG weld outdoors in calm conditions. However, it can still be a challenge. One widely available solution is a combo machine designed for outdoor use that includes stick welding, another option among the different types of welding.

Weld Speed

TIG welding is a slower process than MIG welding. This is partly due to welders’ need to coordinate the actions of both hands. There’s also the physical restriction of manually feeding the filler rods into the weld pool one at a time. For these reasons, it isn’t possible to TIG weld as quickly as with MIG’s automated wire.

The upside of TIG welding is greater control. The weld pool is comparatively small, making TIG a better choice when the appearance of a weld is important. This process also makes it possible to weld thinner material than can be done with MIG.

Weld Strength

Because TIG welding produces smaller and neater welds than MIG, it’s ideal for welding thinner materials. Also, the intensity of the welds penetrates material more deeply, so TIG weld strength is greater.

The process starts with the wire electrode and shielding gas being fed through the welding gun or torch. Remember, the wire diameter and composition will vary depending on the joint configuration, part thickness, and types of metal being joined. Furthermore, the wire feed speed (WFS) settings determine the pace and the amount of the wire being fed.

MIG Welding Benefits

1. Good for thicker metals

2. Less complex

3. Lower overall costs

What Happens During the TIG Welding Process?

The TIG welding technique also incorporates an arc. However, it uses a non-consumable tungsten electrode and a separate filler material to create the weld. The filler is mostly a rod manually fed into the weld pool. It means both hands are used during this process, one for the tungsten electrode and the other for the filler material.

The shielding gas mixture is 100% argon. CO2 isn't utilized in TIG welding because of its reactive properties that cause tungsten oxide formation. Tungsten oxide breaks down the tungsten electrode, which contaminates the weld.

TIG Welding Benefits

1. Joins a wide variety of small and thin metals

2. Greater control over the welding operation

3. TIG welds are precise and more robust

MIG vs TIG Welding Distinctions

The differences between MIG and TIG welding don't stop there. Many other factors differentiate their weld characteristics. Below is a breakdown of these distinctions:

1. Weld strength: TIG welds are stronger than welds produced through MIG. It's mainly due to the narrow arc used in TIG welding that's better at penetrating the metal. In addition, TIG beads have fewer defects than MIG beads, so the joints are more resilient.

2. Weld speed: MIG welding is faster than TIG welding, which is why the latter is more expensive. Since welders must use two hands to operate the TIG process, it's more time-consuming than MIG welding.

3. Welding gas: TIG welding uses argon gas to prevent tungsten deterioration. Meanwhile, MIG welding uses a blend of argon and CO2 because carbon dioxide stabilizes the arc and provides better penetration.

4. Weld aesthetics: TIG beads are professional and good-looking because there are fewer splatters and discolorations, which can be solved with light polishing.

However, it doesn't mean that MIG welds are ugly because a good welder can produce beads that match the project's requirements.

MIG Welding Applications

The high speed, low cost, and relative simplicity of MIG welding have helped push it to the top of the pile when it comes to metal-joining processes. It's used everywhere, from component repairs and automotive manufacturing to pipe-welding and ship building.

For thicker metals and larger parts, MIG welding is the only choice: TIG welding can't penetrate deep enough to heat the material for a good weld. MIG welding is also found where a low defect rate is important: As a simpler welding process which operates continuously, without the foot-operated stop-and-start approach of TIG welding, severe defects become less likely.

TIG Welding Applications

The complexity of TIG welding means it's relatively expensive, a problem exacerbated by its slow weld rate and the need for an experienced operator. It's not a process you'd typically use for something as simple as welding together lengths of pipe, but it certainly has its applications.

The aesthetics of TIG welds, particularly when carried out on well-fitting parts with no filler rod, make it ideal for user-facing projects and luxury goods - but the technology isn't all about looks. TIG welds are found on sheet metal parts in the aerospace and automotive industries where their smooth finish improves efficiency, while their higher weld strength compared to MIG welds make them ideal for high-risk environments - which is why nuclear waste storage containers are manufactured and sealed using TIG, rather than MIG, welding.

MIG welding is best for joining thick or large materials, while TIG welding is better for thin or small pieces.

Both MIG and TIG can produce a variety of different types of welds in steel, stainless steel, and aluminum. Generally speaking, however, the speed and power of MIG welding is better suited to more substantial projects. MIG is a great choice for hobby welders interested in auto repair, building steel furniture, or creating steel sculptures for the garden.

While MIG welding stainless steel and aluminum is possible, TIG welding is generally considered the better option with these materials. Stainless steel and aluminum are more susceptible to heat variations and can be tricky to weld well. When thin stock is used, TIG offers a higher degree of control and results in smaller, neater welds. Once the technique is mastered, TIG welders can achieve a fine finish requiring little or no clean-up work before finishing.

Because TIG welding is more technically demanding, MIG is easier to learn for beginners.

MIG welding is invariably considered the best type of welding for beginners. The technique is easier to learn and more forgiving. Most welders start out working with ordinary steel (aka mild steel), which the MIG welding process is ideal for. High quality MIG welding equipment suitable for beginners is usually less expensive than TIG welding equipment.

TIG welding requires both hands, and while the power control may be located on the main unit, many machines use a foot pedal. This, of course, involves increased coordination. The reward for learning TIG welding is the ability to weld a wider range of materials and produce more precise, higher quality work. However, patience is required and the TIG process cannot be rushed. Taking a welding course is always a good idea for beginner welders and highly recommended for those who want to learn how to TIG weld.

Conclusion

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Contact IDEAL today to see how we can assist with your next project!