Final answer:
Failure to purge with nitrogen while brazing can result in oxidation, leading to a weakened joint, potential system failures, and long-term corrosion issues. Nitrogen purging is crucial to maintain joint integrity and prevent contamination.
Step-by-step explanation:
Not purging with nitrogen while brazing can have several negative consequences. When metals are heated during the brazing process, they can react with oxygen in the air to form oxides. These oxides can contaminate the brazed joint, resulting in a weaker bond that is more prone to failure. The use of nitrogen is to displace the oxygen around the joint area, preventing this oxidation.
Without nitrogen purging, the resulting oxides can create a layer that inhibits the flow of the filler metal, causing it to not properly wet the metal surfaces. This means the filler metal may not spread as it should to form a strong joint. Moreover, if oxides get entrapped in the joint, they can lead to voids or weak spots within the brazed connection. These can ultimately lead to leaks, especially in piping systems, or mechanical failure under stress.
Additionally, the presence of oxides can also reduce the thermal and electrical conductivity of the joint, which is particularly problematic in electrical or refrigeration systems. In some cases, not purging with nitrogen can also lead to longer-term corrosion issues, as the oxides can interact over time with the metals and the environmental conditions to cause further deterioration.
Without nitrogen purging during brazing, oxidation occurs, leading to contaminated, weaker joints and potential long-term system failures. It's crucial for maintaining joint integrity and system reliability.