ICC Commercial Mechanical Practice Exam

What does a brazed joint provide between metal parts?

1. A strong connection at high pressure

2. A permanent gas-tight seal

3. A waterproof joint

4. A flexible connection

The correct answer is: A permanent gas-tight seal

A brazed joint provides a permanent gas-tight seal between metal parts, making it highly effective for applications where leakage would be a concern, such as in piping systems for fluids and gases. The brazing process involves melting a filler metal that has a lower melting point than the base metals being joined, usually above 450°C (about 840°F). When this filler metal cools and solidifies, it bonds with the base metals to form a robust joint that is resistant to both thermal and vibrational stresses. This joint's ability to create a gas-tight seal is especially critical in situations involving high temperatures and pressures, as it minimizes the risk of leaks. Unlike some other joining methods, which may allow for some movement or flexibility, brazed joints are intended to create a rigid and fixed bond, ensuring that the joint does not fail under operational stresses. This characteristic is crucial for maintaining system integrity in applications ranging from refrigeration to HVAC systems.