Which joining process uses a filler metal that melts at a temperature range but does not melt the base metals?

• A. Welding
• B. Soldering
• C. Brazing
• D. Solid State Welding

Answer: (C)

Brazing involves using a separate filler metal that melts and flows into the joint while the base metals stay solid. The parts are heated until the filler metal reaches its liquidus, then capillary action pulls the molten filler into the gap; upon cooling, a strong bond forms without melting the base metals. This distinguishes brazing from welding, which melts the base metals to fuse them, and from solid-state welding, which joins without melting anything. Soldering also uses a filler metal that melts and flows without melting the workpieces, but the filler metal’s melting point is much lower than brazing, which is a helpful distinction in practice.