FAA Aviation Mechanic General (AMG)Materials, Hardware and ProcessesEasy
A technician needs to join two pieces of thin-wall 4130 steel tubing on a fuselage cluster without melting the base metal. The filler metal selected flows and bonds at a temperature above 800°F but below the melting point of the tubing. Which joining process is being performed?
- ABrazing
- BFusion (gas) welding
- CRiveting
- DSoldering
Show answer & explanationAnswer & explanation
Correct answer: A. Brazing
Brazing is defined as joining metals with a filler that melts above 800°F but below the base metal's melting point, bonding by capillary action without fusing the base metal. Soldering uses filler below 800°F, and fusion welding melts the base metal itself.
Why the other options are wrong
- B. Fusion welding melts and fuses the base metal, unlike brazing.
- C. Riveting is a mechanical fastening method, not a thermal joining process.
- D. Soldering filler melts below 800°F, too low for this description.
Brazing
A joining process using a nonferrous filler metal with a melting point above 800°F but below that of the base metal, bonded by capillary attraction.
- Filler melts >800°F but below base metal melting point
- Base metal is not melted
- Common fillers include silver and brass alloys
Memory trick: Solder low, Braze in-between, Weld melts the metal