In welding, what does the term 'impurities' typically refer to?

In welding, the term 'impurities' refers to foreign materials that can contaminate the weld joint and adversely affect the quality and strength of the weld. Impurities may come from various sources, such as the base materials, the filler metal, or the welding environment. Examples include rust, oil, paint, and moisture. These contaminants can cause issues like porosity, reduced weld penetration, and increased susceptibility to cracking, ultimately compromising the integrity of the weld.

Understanding and controlling impurities is essential for producing high-quality welds that meet specified standards. This knowledge is critical for metal fabricators, as it impacts the overall performance of the welded structure and the safety of the final product.