What does the term "slag" refer to in welding?

The term "slag" refers specifically to the byproduct that forms on the surface of molten metal during welding. This material is produced during the welding process as a result of the reactions between the molten metal and impurities, such as oxides and other materials that may be present. Slag serves a protective function by covering the molten weld pool, helping to prevent contamination from the atmosphere and promoting a stronger bond once the weld cools and solidifies.

Understanding slag is important for welders because its presence can impact the quality and integrity of the weld. Properly managing and removing slag is a crucial part of finishing a weld to ensure that it meets the required specifications and standards. In contrast, a type of welding rod refers to the tool used to create the weld, molten metal signifies the actual material being joined, and safety hazards pertain to the risks present in the working environment rather than byproducts of the welding process itself.