What common defects could result from insufficient cleaning of the base metal before welding?

• A. Weld spatter
• B. Inclusion defects
• C. Cracking
• D. Overlapping

Answer: (B)

Inclusion defects occur when impurities, such as rust, dirt, or grease, are present on the base metal before the welding process begins. If the base metal is not properly cleaned, these contaminants can become trapped within the weld pool as it solidifies, leading to inclusions. These inclusions can weaken the weld and result in diminished structural integrity, making this defect particularly important to address when preparing for welding. Proper cleaning techniques, such as grinding, brushing, or chemical cleaning, are essential to eliminate these surface contaminants to ensure a sound weld.

Other defects mentioned, like weld spatter, cracking, and overlapping, can result from various factors unrelated to the cleanliness of the base metal. For example, weld spatter is typically caused by excessive heat or improper technique during welding. Cracking can arise from thermal stresses or inadequate weld metal properties rather than the presence of contaminants. Overlapping occurs when the weld puddle does not sufficiently penetrate the base metal, which can happen due to improper angles or technique rather than surface condition alone. Thus, inclusion defects specifically highlight the critical nature of base metal preparation prior to welding.