GUIDE TO DISTINGUISHING TIG WELDING AND MIG WELDING
Thursday, 24/03/2022 | 22:12 13245 Views
Below Weldcom will present the differences between TIG welding and MIG welding, guide you on when to use a TIG welder, when to use a MIG welder, and the applications of these two welding methods in manufacturing.
1. What is TIG Welding?
TIG Welding (Tungsten Inert Gas), also known as Gas Tungsten Arc Welding (GTAW), is arc welding using a non-consumable tungsten electrode in a shielding gas environment, commonly called Argon welding or WIG (Wolfram Inert Gas). Various shielding gases are used such as: Argon, Helium, Argon+Helium, Argon+Hydrogen, or Argon+Oxygen.
Features of TIG Welding
Non-consumable electrode. Does not create slag because no welding flux is used. The arc and weld pool can be easily observed and controlled. Concentrated heat source with high temperature. Can weld thin or thick metals due to the wide adjustment range of welding parameters (from a few amps to several hundred amps).
Can weld most metals and alloys with high quality. Weld joints are clean and beautiful, without slag inclusion and spatter. Penetration depth and weld pool shape can be easily controlled.
Can use or not use filler rod to create the weld joint.
Applications of TIG Welding
The TIG welding method is applied in many manufacturing fields, especially suitable for welding high-alloy steels, non-ferrous metals and their alloys. This welding method is usually operated manually and can automate both arc movement and filler wire feeding. It is commonly used in the aerospace industry and space vehicle manufacturing.
Used for welding thin sheets and thin-walled tubes in the bicycle industry. Commonly used in the restoration and repair process of damaged parts, especially parts made of aluminum and magnesium.
TIG welding is particularly applied in difficult welding details requiring high-quality weld joints, such as small, hard-to-reach corners in machine parts, photocopier casings, refrigerators, air conditioners, various hospital machines such as X-ray machines, projectors, etc. Widely applied in ship welding, pipe welding, gas and oil pipeline welding.
Can weld thin or thick metals due to the wide adjustment range of welding parameters (from a few amps to several hundred amps). Can weld metals and alloys with high quality. Weld joints are clean and beautiful, without slag inclusion and spatter. Penetration depth and weld pool shape can be easily controlled. Can use or not use filler rod to create the weld joint.
Disadvantages of TIG Welding
– Low productivity.
– Requires highly skilled welders.
– Relatively high cost due to low productivity, and equipment and materials are expensive.
Laser welding has high productivity and does not require high skill levels → Learn more: Handheld Mini Laser Welding Machine
Materials Suitable for TIG Welding
Steel alloys: stainless steel (inox), low carbon alloys (mild steel or black steel)
Aluminum alloys, Copper alloys, Magnesium, Alloy cast iron, Nickel, Zinc alloys, Zirconium alloys...
For beginners entering the welding profession, it can be simply understood as follows: To fill the arc into the welding location, we use TIG welding equipment including: Welding machine, Welding gas, Power source, Welding torch... Connected together according to a standard system, after checking that the system operates well, we start welding. The simple principle is that under the effect of electric current, an important part in the welding torch called the non-consumable electrode (Welding tungsten) will emit a very large amount of heat. When we feed the filler rod into the arc area, the heat from the arc will melt the filler rod and fill the weld joint.
2. What is MIG Welding?
MIG (MAG) welding is a welding method belonging to the GMAW process group, using heat from the arc burning between a solid electrode wire continuously fed by a wire feeder at a constant speed. The molten pool formed is protected by inert gas flow (MIG) or active gas flow (MAG). This method is also called semi-automatic welding, however that name is not accurate. In industry, MAG welding with CO2 shielding gas is commonly called wire welding or CO2 welding.
MIG Welding Equipment
The most important equipment is the welding torch, which handles functions such as supplying welding current to the welding wire through the contact tube, shielding gas through the nozzle, and cooling system for the welding torch when needed.
The second piece of equipment is the wire feeder with stable speed at set values. Depending on the welding wire type, 2-roll or 4-roll wire feeders can be used. The wire feeder can be separate or built into the welding power source. The function of the wire feeder is to maintain the automatic burning process of the arc after ignition.
Shielding Gas for MIG Welding
Shielding gas can be inert gas (Ar, He or mixture Ar + He) that does not react with liquid metal during welding, or active gas types (CO2; CO2 + O2; CO2 + Ar, ...) that displace and push air out of the welding area to limit its harmful effects.
– CO2 is a gas that is easy to find, easy to produce, and low cost. Welding productivity in CO2 is high, more than 2.5 times compared to manual arc welding. The technological properties of welding in CO2 are higher than submerged arc welding because it can be performed in various spatial positions.
– High welding quality. Welded products have less deformation due to high welding speed, concentrated heat source, high heat utilization efficiency, and narrow heat-affected zone. MIG weld joints are usually well-penetrated and beautiful; if the welder is skilled, very beautiful weld beads can be produced.
– Can weld various metals: steel, stainless steel, aluminum... Working conditions are better compared to manual arc welding and the welding process does not generate toxic gases.
Application Scope of MIG Welding
Not only can it weld common structural steels, but it can also weld various stainless steels, heat-resistant steels, high-temperature steels, special alloys, aluminum alloys, magnesium, nickel, copper, and alloys with strong chemical affinity for oxygen.
This welding method can be used in all spatial positions and is widely used in manufacturing various products such as furniture, motorcycles, bicycle frames, or used in shipbuilding, automobile body assembly, mechanical workshops, manufacturing production lines...
Material thickness from 0.4 - 4.8mm only requires single-layer welding without beveling; from 1.6 - 10mm requires single-layer welding with beveling; and from 3.2 - 25mm requires multi-layer welding.
Not suitable for outdoor welding, because surrounding air movement can affect the shielding gas and the weld joint.
Therefore, its use in the construction industry is quite limited. Widely used in automatic and semi-automatic welding.
Simply put: In MIG welding, the arc from the welding wire will melt and form an arc that fills the weld joint.
MIG and MAG welding machines are essentially the same type of machine. But when used for different work, they differ. With MIG welding, people use welding wire without flux core inside, so 100% inert gas such as argon or helium must be used. This way, the weld joint does not have gas porosity and will be very shiny, with no slag after welding.
Meanwhile, when we see people welding with that type of machine using flux-cored welding wire and CO2 or Ar + CO2 gas, that is MAG welding. Because even though there is flux inside, CO2 or Ar + CO2 must be used to push impurity gases out of the weld joint, otherwise the weld joint will have gas porosity.
3. When to Use MIG Welding and When to Use TIG Welding?
This question actually depends on the welder's purpose: prioritizing weld joint quality or prioritizing production efficiency. However, there are some basic differences for choosing MIG or TIG welding:
Very thin materials around 0.6mm - 0.8mm, such as various machine casings: printer casings, X-ray machine casings, projector machines, or various machines with thin and delicate structures, are difficult to apply MIG welding. In this case, TIG welding must be used to avoid deformation and material damage.
Additionally, difficult-to-weld details such as small, hidden corners requiring internal welding where the MIG welding torch cannot reach - in this case, TIG welding is mandatory.
– For welding thick materials, we can choose either TIG or MIG welding. Usually, for these materials, MIG welding is mostly applied to increase productivity and reduce product welding time.
– Currently, the application of industrial welding robots in production is becoming widespread, helping increase work productivity, with uniform and beautiful weld joints. Many mechanical workshops and manufacturing plants have been using them and provide very positive feedback when using welding robots.
Click time： Update time：2020-08-13 13:21:46 【print】 【close】