What is a Defect in Welding?
A discontinuity or discontinuities that by nature or accumulated effect (for example, total crack length) renders a part or product unable to meet minimum applicable acceptance standards or specifications.
In welding, a defect is any flaw that compromises the usefulness of the finished product. Although some defects can be accepted, others require rejection and repair.
What are the 5 weld defects?
There are different types of welding defects. Some of the more common ones are:
- Porosity: This is when gas bubbles become trapped in the weld metal. Porosity can weaken the joint and make it more susceptible to corrosion.
- Inclusion: Inclusions are foreign materials that become trapped in the weld pool. They can cause internal stresses that can lead to cracking.
- Undercut: Undercut is when the weld metal erodes the base metal around the edge of the weld. This can weaken the joint and make it more susceptible to corrosion.
- Lack of Fusion: Lack of fusion occurs when the weld metal does not bond to the base metal. This can lead to cracking and weakening of the joint.
- Reinforcement: Reinforcement is when the weld metal protrudes above the surface of the base metal. This can make the joint weaker and more susceptible to cracking.
Welding defects can be caused by a number of factors, including:
- incorrect welding parameters,
- and poor technique.
How to avoid defects?
To avoid defects, it is important to use the correct welding parameters and follow proper welding procedures.
Good to know:
1)Root concavity weld defect
It is a result of gas entrapment.
2) Visual control welding
It is the most common method used to control the quality of a weld. This method can be used to detect defects such as porosity, slag inclusion, and lack of fusion.