How does moisture content in filler material affect the weld?

Moisture content in filler material significantly impacts the quality of the weld, primarily by potentially leading to hydrogen-induced cracking. When moisture is present in the filler material, it can evaporate during the welding process, producing hydrogen gas. This hydrogen can dissolve into the weld metal. If the weld solidifies while hydrogen is still present, it can lead to the formation of cracks as the metal cools and constrains the dissolved hydrogen. This form of cracking typically occurs in high-strength steel and is particularly problematic because it can compromise the integrity of the weld joint, making it much less reliable and more prone to failure under stress.

Understanding the severity of moisture content helps in ensuring the integrity of the welding process. Proper storage and handling of filler materials to keep them dry and free of contaminants is essential to produce high-quality welds. The other options do not accurately reflect the effects of moisture on the welding process; they either misinterpret the role of moisture or suggest that it has a negligible or positive impact, which is not the case in the context of hydrogen-induced cracking.