Types of Welding Processes (Uses, Advantages & Disadvantages) – Engineering

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The intriguing process of welding dates back to 1904, when the coated electrode was first created. To put it more simply, welding is the process of joining different pieces of metal together by first melting them and then fusing them together.

A welding power source is necessary for the welding process because it is necessary to generate an electric arc in order to melt the base material being welded as well as any consumables used. As a result, previously separate metals are now bonded together. There is a wide variety of welding techniques; however, the following is an overview of the four most frequently used types of techniques.

Gas and Metal Arc Welding – MIG (GMAW)

This technique, also known as MIG or Metal Inert Gas welding, uses a small wire as the electrode. As the wire is fed through the welding equipment and to the welding location, it heats up. This approach requires a power supply with constant DC voltage and current. A shielding gas should be used to protect the weld from airborne pollutants.

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Usually carbon dioxide, argon or their combination is used. This technique is frequently applied to a variety of metals, including stainless steel, copper, nickel, carbon steel, and aluminum.

Uses

This welding technique is the most used in the construction and automotive sectors. MIG welding is most often used to repair automobiles, motorcycles, recreational vehicles, vans and SUVs. MIG welding is the ideal technology for assembling or repairing the body or interior of any car, as it can produce a strong weld even for the finest metals. Including large bore plates and pipes, and is the most common industrial welding method.

Advantages

  • Gas arc welding is one of the easiest procedures to master, making it perfect for beginners.
  • It allows for fast welding speeds, minimal cleanup and better control on thinner materials.
  • MIG welding provides clean, attractive welds.

The inconvenients

  • Some disadvantages of this welding technique include the cost of shielding gas and the inability to weld heavier metals or perform vertical or overhead welding.
  • These types of welding are prone to external elements such as rain, wind and dust, making them unsuitable for outdoor use.
  • MIG welding quality issues include slag and porosity, which weaken the structure.

Gas tungsten arc welding – TIG (GTAW)

TIG welding, unlike other forms of welding, uses a tungsten electrode to produce the weld. A gas tank is required for TIG welding to provide a constant flow of shielding gas, often argon or a mixture of argon and helium. This indicates that it is generally best accomplished indoors and out of the environment. Due to the short distance between the arc and the area to be welded, this process requires great precision and skill. This approach produces welds renowned for their extraordinary strength.

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It is one of the few welding methods that can be achieved using only the two metals to be welded. If desired, you can add filler metal, but it must be manually fed. The heat and arc produced by the torch are used to weld the majority of conventional metals, such as aluminum, steel, nickel alloys, copper alloys, cobalt and titanium.

Uses

Steel, stainless steel, chromoly, aluminum, nickel alloys, magnesium, copper, brass, bronze and even gold can be welded with TIG welders. TIG is a suitable welding technique for bicycle frames, lawn mowers, door handles and bumpers, among others.

Advantages

  • Due to the short distance between the arc and the region to be welded, the highest quality welds are produced.
  • TIG welding is a precise process that produces visually beautiful welds and does not require cleanup due to the absence of spatter.

The inconvenients

  • Mastering it requires an immense amount of precision and skill.
  • A gas tank is required for TIG welding to provide the constant gas flow needed to protect the weld, which makes it more expensive.
  • This indicates that it is generally best done indoors and sheltered from the weather.

Metal shielded arc welding – stick (SMAW)

These welding methods have been used for decades, if not centuries, with only minor adjustments made from time to time. A stick welder has a power source and large cable leads with an electrode holder on one lead and a work clamp on the other. The electrode is a metal rod, similar to a thick section of wire. They are available in many metals and alloys.

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There is a variation in the diameter of the welding rods. It is chosen depending on the thickness of the metal. Welding rods are coated in a thick layer of flux, a substance that burns in the arc to produce shielding gas for the weld pool. As the metal cools, the flux produces a thin, brittle crust called slag, which must be removed by chipping or brushing.

Uses

Stick arc welding is suggested when it is difficult to reach the weld or when rust, oil or other impurities are present at the weld joint. It works effectively on steel, cast iron, aluminum, stainless steel and hard surface farm equipment.

Advantages

  • Because shielded arc welding requires minimal equipment, it is inexpensive.
  • This type of welding does not require shielding gas and can be done in wind or rain.
  • It is perfect for repairing rusted, painted and dirty equipment.
  • Quickly interchangeable electrodes simplify the welding of different metals.

The inconvenients

  • Stick welds do not yield the highest quality products.
  • They are sensitive to porosity, cracking and surface penetration.
  • In general, stick welds are less durable than those produced by other forms of welding.
  • It is not recommended for thin metals.

Flux-cored arc welding (FCAW)

This welding method is quite similar to the MIG welding technique. Many MIG welders are also capable of performing the duties of FCAW welders. A wire that acts as an electrode and filler metal is fed through your rod in the same way as in MIG welding. This is where things start to diverge from each other.

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When performing FCAW, the wire has a flux core, forming a gas shield around the solder. As a result, it is no longer necessary to have an external gas supply. However, there are two distinct varieties of FCAW: the first uses a shielding gas and the second depends on self-protecting agents generated when fluxes break down inside the wire itself.

Uses

FCAW is suitable for thicker and heavier metals due to its high temperature welding characteristics. For this reason, it is frequently used for heavy machinery repairs. It is an efficient procedure that generates little waste. Due to the volume of smoke and fumes produced during the welding process, flux-cored arc welding should be performed outdoors or under industrial ventilation hoods.

Advantages

  • This welding technique is renowned for being economical and simple to master.
  • It is effective on dirt, paint and corrosion and can be used in windy situations.
  • The welding procedure is efficient and effective for welding heavy metals at high temperatures.

The inconvenients

  • This generates a lot of spatter and the slag needs to be cleaned up.

You can also watch the demonstration of four main types of welding in this YouTube video;

Some other welding techniques

Plasma arc welding

Plasma arc welding is comparable to GTAW; however, using a smaller arc improves weld accuracy. Additionally, it uses a separate torch that reaches much higher temperatures. The plasma is formed by pressurizing the gas inside the rod. Once the plasma is ionized, it becomes electrically conductive. This allows the creation of arcs, which generate extremely high temperatures capable of melting base metals. This allows plasma arc welding without filler metal, another similarity to TIG welding.

Normal gas mixtures consist of argon for plasma gas and argon plus 2-5% hydrogen for shielding gas. Helium can be used as a plasma gas, but due to its higher temperature, the nozzle current rating is reduced. This technology is used by the aeronautical industry but is of no use for enthusiasts and DIY enthusiasts.

Atomic hydrogen welding

Atomic hydrogen welding, formerly known as atom arc welding, is an exceptionally high temperature welding technique. It is an ideal material for tungsten welding. This form of welding involves shielding two tungsten electrodes with hydrogen gas. It can reach temperatures higher than an acetylene torch, and hydrogen molecules in explosive heat can generate temperatures of up to 3000 degrees Celsius.

Essential safety precautions include welding gloves, coveralls, goggles and helmets. It is possible with or without filler metal. This is an earlier welding method that has been superseded in recent years by MIG welding.

Electron beam welding

It is a form of welding in which a high-speed electron beam generates heat by kinetic energy, thereby joining two materials. This is a very advanced form of welding that is often done by vacuum machines. This type of welding is used in various industries, including the automotive and aero engine industries.

It is a useful device for aerospace components, bi-metal saw blades and transmission systems. It is ideal for sealing electrical components. The method is applicable to dissimilar metals with different melting points and thermal conductivities. This welding technique is suitable for thin and thick metals.

Which welding process is the strongest?

The material to which a weld is applied determines its strength. Additionally, the length, size, and filler of the weld can also affect the strength of a weld. Each welding process, whether MIG, TIG, Stick or Flux Cored, has distinct advantages and disadvantages over the others.

However, TIG welding is generally considered the strongest type of welding due to its high heat output and delayed cooling rate, resulting in high tensile strength and high ductility.

Conclusion

Although there are many other ways to solder, the four techniques listed above are the most common. Some processes are performed by machines and can be done by an amateur at home and do not require a large financial investment. On the other hand, others require specialized and expensive tools and an expert.


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