Which condition regarding visible lack of fusion is acceptable according to AWS D1.1?

In accordance with AWS D1.1, the standards for weld quality and integrity are stringent, particularly concerning the absence of defects such as lack of fusion. The requirement for no visible lack of fusion underscores the necessity for welds to adhere to high-quality benchmarks, which are crucial for ensuring the structural integrity and longevity of welded components.

A lack of fusion indicates that the base materials have not properly bonded together during the welding process, which can lead to significant weaknesses in the weld joint. The absence of any such visible defect ensures that the weld is sound, with complete fusion achieved between the weld metal and the base metal. This approach helps to prevent potential failure points, thus ensuring safety and reliability in welded constructions.

Options that suggest a minor, moderate, or severe visible lack of fusion are not acceptable, as any degree of lack of fusion can compromise the strength and performance of the joint. Consequently, the requirement for no visible lack of fusion is a firm standard aimed at maintaining the highest quality in welding practices.