What is Arc Welding? | Types Of Arc Welding

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.

In another way, arc welding is a welding process in which metal is joined to metal by using electricity to generate enough heat to melt metal, and the melted metals when cool result in a binding of the metals. This type of welding uses a welding power supply to create an 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 current or alternating current and consumable or non-consumable electrodes. The welding area is usually protected by some kind of shielding gas, vapor, or slag. Arc welding processes can be manual, semi-automatic or fully automatic.

Arc welding, first developed in the late 19th century, became commercially important in shipbuilding during World War II. Today it remains an important process for the manufacture of steel structures and vehicles.

How Does it Work?

Arc welding is a fusion welding process for joining metals. An electric arc from an AC or DC power supply creates intense heat of around 6500°F, which melts the metal at the joint between two workpieces.

The arc can be guided either manually or mechanically along the joint line, while the electrode either simply carries the current or conducts the current and at the same time melts into the weld pool to add filler metal to the joint.

Since the metals react chemically to oxygen and nitrogen in the air when they are heated to high temperatures by the arc, a protective shield gas or slag is used to minimize contact of the molten metal with the air. After cooling, the molten metals solidify to form a metallurgical bond.

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.
Arc welding

Types of arc welding

Arc Welding can be categorised into two different types;

  • Consumable Electrode Methods
    • Shielded metal arc welding.
    • MAG welding.
    • MIG welding.
    • Electrogas arc welding (EGW)
  • Non-consumable Electrode Methods
    • TIG welding
    • Plasma welding

Consumable Electrode Methods:

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.

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: versatile, economical, simple, low temperatures and easy to automate. This is a popular welding technique for thin sheets and profiles.

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.

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 spatter. This method allows heat to penetrate deeper as it acts like 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.

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.

Flux-cored arc welding (FCAW)

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

Non-consumable Electrode Methods:

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.

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

  • Shipbuilding
  • Automotive industries
  • Construction industries
  • Mechanical industries

Advantages of arc welding

  • High Welding Speed
  • Produces Very Less Distortion
  • Less Smoke or Sparks are Involved
  • Smooth Welding is Achieved
  • Can be Carried Out in Any Atmosphere
  • Cheap Cost
  • Good Impact Strength
  • Higher Corrosion Resistance

Disadvantages of arc welding:

  • Not suitable for welding thin metals
  • Requires skilled welders
  • 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.

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