What is Discontinuity in Welding?

Discontinuity is an interruption of the typical structure of a material, such as a lack of homogeneity in its mechanical, metallurgical, or physical characteristics. A discontinuity is not necessarily a defect.

However, in welding, discontinuities can create potential problems. For example, cracks are one type of discontinuity that can form in welds. Cracks can weaken the weld and cause it to fail.

What is the difference between weld defect and discontinuity?

  • A weld discontinuity is an interruption of the typical structure of a material, while a weld defect is a type of discontinuity that impacts the function or quality of the weld.
  • Weld defects are usually caused by human error, while discontinuities can occur naturally.

What are the common weld discontinuities?

The most common weld discontinuities are:

  • incomplete fusion,
  • slag inclusion,
  • porosity,
  • undercut and more.

How do you prevent weld discontinuities?

There are many ways to prevent weld discontinuities, including:

  • using the correct welding procedure,
  • using the correct welding consumables and more.

Do all welds have discontinuities?

No, not all welds have discontinuities. However, all welds will have some level of imperfection. It is important to remember that even though a weld may have some discontinuities, it does not mean that the weld is defective.

Underfill in welding

It is an example of a weld discontinuity that does not necessarily impact the quality or strength of the weld.

Related Links

Types of discontinuities (video) | Khan Academy
Discontinuity — from Wolfram MathWorld
Classification of discontinuities
What are the types of Discontinuities, Explained with graphs, examples and interactive tutorial

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