What does AWS D1.1 state regarding the removal of slag from completed welds?

The reason why the removal of slag from completed welds is defined as necessary in AWS D1.1 is that slag can negatively impact the integrity and performance of the weld. If left in place, slag can lead to issues such as fatigue and corrosion by creating areas where moisture and contaminants can accumulate. This buildup can ultimately compromise structural strength and durability.

Moreover, slag can interfere with the bonding process in subsequent welding operations, thereby impairing the quality of future joints. AWS D1.1 emphasizes the importance of maintaining high-quality welds for safety and structural reliability, making the removal of slag an essential step in the welding process to ensure that the welds are sound and free from defects that could lead to failure under load.

In contrast, options that suggest that slag removal is only for aesthetic reasons, is optional, or that only visible slag should be removed do not align with the critical emphasis that AWS D1.1 places on the structural implications of weld quality. Thus, the correct understanding is that effective slag removal is a key component in maintaining the integrity and longevity of welded structures.