Arc Welding: Definition, Types & How Does it Work?

What is Arc Welding?

Arc welding is a welding process that is used to join metal to metal by using electricity to create enough heat to melt metal, and the melted metals, when cool, result in a binding of the metals. It is a type of welding that uses a welding power supply to create an electric arc between a metal stick (“electrode”) and the base material to melt the metals at the point of contact.

Arc welders can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding area is usually protected by some type of shielding gas, vapor, or slag.

Arc welding processes may be manual, semi-automatic, or fully automated. First developed in the late part of the 19th century, arc welding became commercially important in shipbuilding during the Second World War. Today it remains an important process for the fabrication of steel structures and vehicles.

How Does Arc welding Work?

Arc welding use­s an electrical arc to melt the work materials as well as a filler material (sometimes called the welding rod) for welding joints. Arc welding involves attaching a grounding wire to the welding material or other metal surface.

Another wire known as an electrode lead is placed on the material to be welded. Once that lead is pulled away from the material, an electric arc is generated. It’s a little like the sparks you see when pulling jumper cables off a car battery. The arc then melts the workpieces along with the filler material that helps to join the pieces.

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Feeding the filler into the welding joint takes steady hands and an eye for detail. As the rod melts, the welder must continuously feed the filler into the joint using small, steady, back-and-forth motions. These motions are what give welds their distinctive appearance. Going too fast or slow, or holding the arc too close or far away from the material can create poor welds.

Shielded metal arc welding (SMAW or stick welding), gas metal arc welding (more commonly known as a metal inert gas, or MIG, welding), and gas tungsten arc welding (frequently called tungsten inert gas, or TIG, welding) all exemplify arc welding.

These three common methods each offer unique advantages and drawbacks. Stick welding, for instance, is inexpensive and easy to learn. It’s also slower and less versatile than some other methods. Oppositely, TIG welding is difficult to learn and requires an elaborate welding rig. TIG welding produces high-quality welds, however, and can weld materials that other methods can’t.

Torch welding represents another popular welding method. This process typically uses an oxyacetylene torch to melt the working material and welding rod. The welder controls the torch and rod simultaneously, giving him or her a lot of control over the weld.

While torch welding has become less common industrially, it’s still frequently used for maintenance and repair work, as well as in sculptures.

Arc Welding
Arc welding

Types of arc welding

Arc Welding can be categorized into two different types;

Electrode consumptionWelding method
Non-consumable (non-fusible) electrode type1. TIG welding
2. Plasma welding
Consumable (fusible) electrode type1. Shielded metal arc welding
2. MAG welding
3. MIG welding
4. Electrogas arc welding (EGW)

1. Consumable Electrode Methods

1.1 Shielded metal arc welding (SMAW)

SMAW is one of the easiest, oldest, and most adaptable arc welding methods, which makes it very popular. The arc is created when the coated electrode tip contacts the weld area and is then withdrawn to maintain the arc. The heat melts the tip, coating, and metal, creating the weld once the alloy solidifies. This technique is typically used in pipeline work, shipbuilding, and construction.

1.2 Gas metal arc welding (GMAW)

GMAW or MIG welding shields the arc with a gas such as argon or helium or a gas mixture. The electrodes have deoxidizers that prevent oxidation, so you can weld multiple layers. This method has several advantages: versatility, economical, simple, low temperatures, and easy to automate. This is a popular welding technique for thin sheets and profiles.

1.3 Metal Inert Gas Welding (MIG) and Metal Active Gas welding (MAG)

Also known as Gas Metal Arc Welding (GMAW), uses a shielding gas to protect the base metals from contamination.

1.4 Submerged arc welding (SAW)

SAW works with a granular flux that, when welded, forms a thick layer that completely covers the molten metal and prevents sparks and spatters. This method allows heat to penetrate deeper as it acts as a heat insulator. SAW is suitable for high-speed welding of sheet metal or steel sheets. It can be semi-automatic or automatic. However, it is limited to horizontal welds.

1.5 Electro-Slag Welding (ESW)

A vertical process for welding thick plates (over 25mm) in one pass. ESW relies on an electric arc to start before adding flux to extinguish the arc. The flux melts when the wire consumable is fed into the molten pool, creating a molten slag on the pool.

Heat to melt the wire and plate edges is generated by the resistance of the molten slag to the passage of electrical current. Two water-cooled copper shoes follow process progression and prevent any molten slag from running off.

1.6 Flux-cored arc welding (FCAW)

This type of arc welding uses tubular electrodes filled with flux. While emissive flows shield the arc from the air, non-emissive flows may require shielding gases. It is ideal for welding dense sections an inch or thicker because FCAW has a higher rate of weld metal deposition.

2. Non-consumable Electrode Methods

1.1 Gas tungsten arc welding (GTAW)/ Tungsten Inert Gas Welding (TIG)

GTAW or TIG welding is often considered the most difficult. Tungsten electrodes create the arc. Inert gases such as argon or helium or a mixture of both are used to protect the shield. Filler wires add molten material if necessary.

This method is much “cleaner” as it does not create slag. It is therefore ideal for welding work where appearance is important, as well as for thin materials.

Check out our article for more info: What is Tungsten Inert Gas Welding?

2.2 Plasma Arc Welding (PAW)

Similar to TIG, PAW uses an arc between a non-consumable electrode and an anode located inside the torch body. The electric arc is used to ionize the gas in the torch and create the plasma, which is then pushed through a fine borehole in the anode to reach the base plate. In this way, the plasma is separated from the shielding gas.

Application of arc welding

The applications of Arc Welding include the following.

  • Used in the welding’s of sheet metals
  • For welding thin, ferrous & non-ferrous metals
  • Used to design pressure & pressure vessels
  • The developments of piping in industries
  • Used in the domains of automotive and home furnishing
  • Industries of Shipbuilding
  • Used in the manufacturer of aircraft & aerospace, Auto body restorations, Railroads.
  • Industries like construction, automotive, mechanical, etc.
  • Gas Tungsten Arc Welding is used in aerospace industries to connect many areas like sheet metals.
  • These welding are used for repairing dies, tools, and mostly on metals that are made with magnesium & aluminum.
  • Most of the fabrication industries use GTAW to weld thin workpieces, particularly nonferrous metals.
  • GTAW welding’s are used where extreme resistance to corrosion as well as cracking over a long period of qualities are required.
  • It is used in space vehicles manufacturing.
  • Used to weld small-diameter parts, thin wall tubing, making it applicable in bicycle industries.

Advantages of arc welding

There are a number of advantages to using arc welding compared with many other formats:

  • Cost: equipment for arc welding is well-priced and affordable, and the process often requires less equipment in the first place because of the lack of gas
  • Portability: these materials are very easy to transport
  • Works on dirty metal
  • Shielding gas isn’t necessary: processes can be completed during wind or rain, and spatter isn’t a major concern
  • High Welding Speed
  • Produces Very Less Distortion
  • Less Smoke or Sparks are Involved
  • Smooth Welding is Achieved
  • Can be Carried Out in Any Atmosphere
  • Good Impact Strength
  • Higher Corrosion Resistance

Disadvantages of arc welding

There are a few reasons why some people look to other options beyond arc welding for certain kinds of projects. These downsides can include:

  • Lower efficiency more waste is generally produced during arc welding than many other types, which can increase project costs in some cases
  • High skill level operators of arc welding projects need a high level of skill and training, and not all professionals have this
  • Thin materials it can be tough to use arc welding on certain thin metals
  • Cannot be used for reactive metals like Aluminum or Titanium

FAQs

What is Arc Welding?

Arc welding is a type of welding process using an electric arc to create heat to melt and join metals. A power supply creates an electric arc between a consumable or non-consumable electrode and the base material using either direct (DC) or alternating (AC) currents.

What are the types of Arc Welding?

Arc Welding can be categorized into two different types;
1. Consumable Electrode Methods
1.1 Shielded metal arc welding.
1.2 MAG welding.
1.3 MIG welding.
1.4 Electro gas arc welding (EGW)
2. Non-consumable Electrode Methods
2.1 TIG welding
2.2 Plasma welding

How Does arc welding Work?

Arc welding is a type of welding process using an electric arc to create heat to melt and join metals. A power supply creates an electric arc between a consumable or non-consumable electrode and the base material using either direct (DC) or alternating (AC) currents.