What characteristics can indicate a poor quality brazed joint?

A poor quality brazed joint can often be identified by the presence of gaps, inclusions, and discoloration. These characteristics are critical indicators of inadequate bonding between the base metals and the filler material. Gaps indicate that the brazing process was not able to fill the joint effectively, leading to weak spots in the assembly. Inclusions, which are typically debris or impurities trapped within the joint, can also diminish the structural integrity and strength of the connection. Discoloration might suggest overheating or contamination, which can also negatively impact the performance of the joint.

In contrast, uniform color and transparency signify a well-executed brazed joint where the filler material has flowed evenly and created a strong connection. High thermal conductivity is often desired in good brazed joints, as it suggests effective heat transfer, but it does not directly relate to the quality of the joint itself concerning integrity. Lastly, minimal flux residue is considered a positive characteristic, as excessive residue might indicate improper cleaning or flux management during the brazing, which can lead to joint deterioration over time.