What Is Undercut Welding?

Welding is an essential manufacturing process with various applications. It is arguably the most important joining process in the manufacturing industry. According to research, undertaking 80% of all production welding processes around the world, arc welding is the most commonly used welding process.

Undercut welding, a widely used arc welding process, has been an integral part of the welding domain, with over 6 million welding robots currently in use.

It is no surprise that an increasing number of businesses are turning towards undercut welding to improve their production processes. So, what is undercut welding, and what makes it so effective and widely used in the manufacturing industry?

What Is Undercut Welding?

Undercut welding is a process in which a weldier creates a weld bead (the melted metal) below the surface of the joint to ensure a strong bond. The process of undercut welding is used in a variety of applications, such as joining two metal pieces, attaching metal fixtures and components, and repairing cracks or defects in metal surfaces.

Advantages of Undercut Welding

Undercut welding is said to have a variety of advantages for welding and fixing metal pieces, some of which include:
  • It provides a more uniform and stronger bond than other welding processes.
  • It provides a better surface finish, which often eliminates the need for grinding, filing, or other post-weld processes.

  • The process is relatively quick and efficient, as undercut welding is typically done in one pass.
  • It provides a neat, attractive finish.

  • It eliminates the possibility of slag formation (a result of oxidization when welding).
  • It reduces warping and distortion of the metal pieces being welded.

Process of Undercut Welding

Undercut welding is an incredibly precise and technical procedure.

When it comes to welding, high levels of safety must be observed at all times. All safety protocols should be observed and followed before any welding can take place.

  • The first step in undercut welding is to prepare the metal pieces. All surfaces must be clean, dry, and free of any dirt, rust, or impurities. This is an important step, as the cleanliness of the metal surfaces will affect the quality of the weld.

  • Once the metal pieces have been prepared, the undercut welding techniques can begin. A weldier typically utilizes a welding torch, which heats the metal to its melting point, creating a molten pool. It is then necessary to trim, or “undercut”, some of the molten metal to create a neat and even weld bead.
  • The weld bead should be smoothed and shaped before the welding process is complete. A weldier should take care to ensure the undercut welding is done evenly across the entire joint, as this will provide a strong, uniform bond.
  • The weld bead should be inspected before the final welding pass to ensure it is straight, uniform, and free of any imperfections.
  • Once the weld bead is inspected, the welding process is complete and the metal pieces can be fused together.


Undercut welding is a versatile and precise welding process used in a variety of applications. When done properly, it can provide a strong, attractive, and uniform bond between two metal pieces. All safety protocols should be observed and followed when welding to ensure a secure, safe weld that functions properly. Citations: https://www. weldingmart. com/blog/what-is-undercut-weldinghttps://en. wikipedia. org/wiki/Weldinghttps://en. wikipedia. org/wiki/Welding_safety

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