How many times can a brazed joint be heated during repairs?

The correct answer indicates that a brazed joint can be heated exactly once during repairs. This limitation is crucial for maintaining the integrity and strength of the joint.

Brazing involves melting a filler metal at a temperature above 450°C (842°F) to join two base metals. When a brazed joint is reheated, it can cause the filler metal to lose its properties, which could compromise the joint's strength and lead to failures. Moreover, each time the joint is reheated, it can potentially alter the microstructure of the base metals, leading to stress and brittleness.

As a result, standards and best practices dictate that a brazed joint should only be heated once to ensure that it retains its original characteristics and provides reliable performance. Understanding this limitation is essential for professionals working with medical gas systems, where safety and reliability are paramount.