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Understanding electro slag welding (ESW)

Today I will be discussing the definition, applications, equipment, diagram, parts, working, advantages, and disadvantages of Electroslag welding ESW. Previously, an article was published on submerged arc welding. checkout!

What is electroslag welding and its working principles

Read more: Understanding shielded arc welding (SMAW)

What is electro slag welding?

Electroslag welding is an arc welding process that generates heat by an electric current. A consumable electrode is used and the weld surface is covered with a molten slag. It is a highly productive, single passing welding process for thick material of about 25mm to about 300mm. It is performed in a vertical or close to a vertical position.

ESW is a combination of both arc welding and resistance welding because, in the beginning, the heat is generated when the electrode is stuck to the workpiece, leading to a melt flux and creating a molten pool on the joint surface. The current now flows between the pool and the heat, developed due to electric resistance.

Applications

The applications of electro slag welding are vast and specialized. However, they are used for the following:

  1. It is used in heavy industries where plate thickness is up to 80 mm to be joined.
  2. Welding of thick-walled large diameter pipes is done by this welding process.
  3. Welding of storage tanks is done by it.
  4. It is used to construct big and thick parts of ships.

Read more: Understanding submerged arc welding (SAW)

Working principles

Working principles of electroslag welding

In the ESW process, firstly the current flow between the welding electrode and the workpiece. It creates an arc between them, which melt the filler wire. The melt filler metal is deposited into the joint area, which solidifies in it. the current flowing will generate heat due to the electric resistance. The heat is used to continuously meltdown the filler metal into the weld zone. The copper shoe and the fed mechanism both move upward until the whole cavity is formed.

Read more: Understanding metal inert gas welding (MIG)

Electro slag welding machine:

The common part in an electro slag welding machine includes an electrode, flux, and electrode guide tube.

electro slag welding machine

Watch the video below to learn the working of electro slag welding ESW:

Read more: Understanding tungsten inert gas welding (TIG)

Advantages and disadvantages of electro slag welding

Advantages

Some advantages of electro slag welding are stated below:

  • Because of the slow cooling rate, cold cracking is avoided
  • The process is semi-automatic and faster
  • Slag remaining is eliminated
  • Heavy parts can be weld
  • Low cost for joint penetration
  • Low distortion

Read more: Working principles of flux cored arc welding

Disadvantages

Despite its good advantages, electro slag welding still offers some disadvantages. The followings are the limitations of this welding process.

  • A slow rate of cooling gives columnar grain to the weld
  • Very high heat applied to the base metals
  • Proper cooling is needed for high temperature applied
  • Only vertical position can be welded
  • Offers low toughness to the weld

Read more: Understanding flux-cored arc welding (FCAW)

That is all for this article, where the definition, applications, diagram, machine, working, advantages and disadvantages of electro slag welding are being discussed. I hope you got a lot from the reading, if so, kindly share with other students. Thanks for reading, see you next time!

 

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