NFPA-99 Practice Exam

What is the consequence of not purging joints correctly during brazing?

1. Increased strength of the joint

2. Formation of contaminants

3. Improved thermal conductivity

4. No significant effect

The correct answer is: Formation of contaminants

When brazing, purging joints correctly is critical to ensuring a clean and effective bond. The primary consequence of not purging joints properly is the formation of contaminants within the joint. Improper purging can leave behind residues such as moisture, oils, or oxidation, which can lead to poor adhesion and weaken the joint. These contaminants can interfere with the flow of the brazing material and create voids or inclusions that compromise the integrity of the joint. By failing to remove these impurities, the strength and reliability of the brazed connection can be significantly affected. Contaminants can lead to corrosion, reduced fatigue strength, and ultimately cause failure of the joint under stress or in adverse conditions. Hence, the importance of purging cannot be overstated in maintaining the quality and durability of brazed assemblies. In contrast, increased strength of the joint, improved thermal conductivity, and no significant effect would unlikely result from improper purging, as those outcomes are typically determined by the quality and cleanliness of the materials being joined.