Why is slag often removed after welding?

Slag removal after welding is crucial for ensuring the integrity and quality of the weld. Slag forms during the welding process as a byproduct, often encapsulating impurities and shielding the molten metal from atmospheric contamination. If left on the weld, slag can lead to defects such as porosity, reduced strength, and compromised weld quality. Removing the slag helps expose the clean weld surface, reducing the risk of future corrosion and enhancing the bond between the weld and the parent materials.

Ensuring a clean weld surface is vital, as contaminants can weaken the joint and potentially lead to failure under load. Therefore, this practice is an essential step in maintaining the performance and durability of the welded joint.

While other options might mention benefits related to surface finish, cooling rates, or facilitating additional welding, the primary concern is the prevention of contamination, which directly affects the quality and strength of the weld.