What are slag inclusions?

Slag inclusions are defined as nonmetallic solids that become trapped in the weld during the welding process. These inclusions can originate from the flux used during welding or from impurities within the base materials. When the molten metal solidifies, any slag that has not been properly removed can become embedded in the weld bead, leading to defects that can undermine the integrity and performance of the weld joint.

In the context of welding, it is crucial to ensure that any slag is removed after each pass in processes that utilize flux, such as shielded metal arc welding (SMAW) and others. By doing so, welders can minimize the risk of inclusions, ensuring sound and high-quality welds that meet the necessary structural requirements. Understanding slag inclusions and controlling them is a vital aspect of maintaining weld quality and ensuring structural integrity in steel fabrication.