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Welding is the process of joining two materials together by the application of heat through an external (electric arc or heaters) or internal entity (friction). Many believe that Welding is a term that is reserved for metals.
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However, that is not true as a material like plastic can also be welded. In this article, we will discuss some of the most common weld techniques used in the industry and where they are used.
The types of welding mentioned here are quite comprehensive but apply only to metals. The following are the most popular metalworking weld methods we use today.
As the name suggests, arc welding uses an electric arc to melt materials before joining them together. The electric arc is brought between the two materials using an electrode (mostly non-consumable electrode).
This electric arc can create temperatures upwards of 3500°C, which is sufficiently high to melt high strength metals like carbon steel. This method also uses shielding gas in conjunction with arc welding.
This is because the atmospheric air can interact with the weld pool and cause oxidation.
There are different types of arc welding such as Shielded Metal Arc Welding (SMAW), Flux-Cored Arc Welding (FCAW), Submerged Arc Welding (SAW), Plasma Arc welding (PAW), etc.
Applications of Arc Welding:
- Automotive industries
- Construction industries
- Mechanical industries
Advantages of Arc welding:
- Suitable for high-speed welds
- Simple welding apparatus
- Portability as a result of the simple equipment
- Can work on AC or DC
- Superior temperatures
Disadvantages of Arc Welding:
- Not suitable for welding thin metals
- Requires skilled welders
- Cannot be used for reactive metals like Al or Ti
MIG or Metal Inert Gas Welding is another welding method that uses an electric arc to create welds. However, when compared with arc welding, MIG requires a consumable electrode to join metals.
A consumable electrode is a metal that supplies electricity to the weld joint. However, the electrode itself undergoes melting when it is near the weld pool.
Hence it gets consumed during the welding process.
In MIG welding, the melted electrode facilitates the joining of the two metals. Hence, MIG is ideal for joining dissimilar metals. Shielding gas is also supplied through the weld gun to ensure that the weld pool does not interact with the atmospheric air.
Some of the popular applications of MIG welding:
- Used for most types of sheet metal welding
- Fabrication of pressure vessels and steel structures
- Automotive industry and home improvement industry
Advantages of MIG welding:
- Creates high-quality welds
- Minor weld splatter
- Can be used to join dissimilar metals
- Can be fully or semi-automatic
- Good weld speed
Disadvantages of MIG welding:
- Unsuitable for outside welding
- Unsuitable for thick metals
- Needs metal preparation
Tungsten Inert Gas welding uses a tungsten electrode to create an arc between the metals. TIG welding is a non-consumable electrode welding method, therefore the tungsten doesn’t get consumed with the process.
TIG welding also doesn’t use any form of flux or slag for shielding. Instead, an inert gas is used as a shielding agent in the entire process. Argon is the most commonly used inert gas in TIG welding.
TIG welding can work on both AC and DC power sources. One of the greatest strengths of TIG welding is that it can be used for welding non-ferrous metals like aluminum, copper, magnesium, copper, nickel, titanium, etc.
Some of the popular applications of TIG welding include:
- Aerospace and aircraft construction
- Automotive industry
- Auto body repairs
Advantages of TIG welding:
- Very clean welds
- Offer a high degree of control to the welder
- Can be used with or without filler material
- Can be done in manual or automatic methods
- Creates strong welds
Disadvantages of TIG Welding:
- Needs skilled welders
- Cannot be used for thicker metal joints
There are two types of flux cored arc welding - Self-Shielded vs. Gas-Shielded Flux-Cored welding.
Self-shielded flux core welding produces slag and gas from the flux that is positioned inside the electrode when they get hot enough. They do not require the use of an external shielding agent.
Gas shielded flux cored welding uses an external gas shielding and flux is only tasked with producing slag. This form of welding gives much more freedom to the welders as they can control the shielding gas quantity and direction.
Flux-cored arc welding uses a consumable electrode for the welding process. FCAW cannot be used on non-ferrous metals like Aluminium, copper, etc.
Some of the popular applications of Flux Cored arc welding are:
- Manufacturing plants
- Industrial piping
- Maintenance and repair
Advantages of Flux Cored arc welding:
- Excellent weld penetration
- Suitable for thicker joints
- Flexibility in terms of torch movement and orientation
- Does not require skilled welders
- The highest metal deposition rate
Disadvantages of Flux Cored arc welding:
- Can result in slag inclusion
- Flux-cored wires are more expensive
- Weld is often not aesthetically pleasing
Gas welding uses the heat from a concentrated flame to melt metals and then join them. Gas welding is possible with or without filler metal.
The flame is controlled using a welding torch. An oxygen gas canister and a fuel gas canister is connected to the welding torch. The welder can control the flame by controlling the number of gases fed to the torch using a pressure regulator.
Most commonly, we see a gas combination of Oxygen and Acetylene which is capable of producing 3200°C. Other fuel gases that are also seen in gas welding are Hydrogen, Butane, & Propane.
Some of the popular applications of Gas welding are:
- Fabrication of sheet metal
- Automobile and aircraft industries
- Joining ferrous and non-ferrous metals
- Joining thin metals
Advantages of Gas welding:
- Easily portable equipment
- Superior flame control
- Low cost and maintenance
- Can also be used for Gas Cutting
- Cheaper equipment cost
Disadvantages of Gas welding:
- Not suitable for very think sections
- Lower temperatures than arc welding
- Harder to flux shield
- No suitable for reactive metals
RELATED: COLD WELDING: JOINING METALS WITHOUT HEAT
Welding is a vast field were new material joining techniques are consistently being developed. The reason for an active interest in this field is because every machinery that we use to create complex and common items require some form of welding.