What is Slag Inclusion?

Slag inclusion is a common welding defect that occurs when molten slag, which is a byproduct of the welding process, becomes trapped within the weld metal. Slag is a non-metallic material that forms on the surface of the weld as a result of the interaction between the welding electrode and the molten metal. When the slag is not removed properly, it can become trapped within the weld metal, resulting in slag inclusion.

Causes of Slag Inclusion

There are several causes of slag inclusion:

Effects of Slag Inclusion

Slag inclusion can have several negative effects on the weld, including:

Prevention and Remedies for Slag Inclusion

The prevention and remedies for slag inclusion depend on the specific cause of the defect. Some general tips for preventing and remedying slag inclusion include:


Slag inclusion is a common welding defect that can have serious negative effects on the weld.