Brazing

Brazing is a <a href="/facts/Metal/pqQVs8QU">metal</a>-joining process in which two or more metal items are joined by melting and flowing a <a href="/facts/Filler_metal/bC80LdUf">filler metal</a> into the joint, with the filler metal having a lower melting point than the adjoining metal.
During the brazing process, the filler metal flows into the gap between close-fitting parts by <a href="/facts/Capillary_action/aa60yQ32">capillary action</a>. The filler metal is brought slightly above its melting (<a href="/facts/Liquidus/RtXE2d8B">liquidus</a>) temperature while protected by a suitable atmosphere, usually a <a href="/facts/Flux_(metallurgy)/ruKFTPGD">flux</a>. It then flows over the base metal (in a process known as <a href="/facts/Wetting/lGloJUzr">wetting</a>) and is then cooled to join the work pieces together.
Brazing differs from <a href="/facts/Welding/6EJ62mYV">welding</a> in that it does not involve melting the work pieces. In welding, the original metal pieces are <a href="/facts/Fusion_welding/AM9H3ESg">fused</a> together without additional filler metal.
Brazing differs from <a href="/facts/Soldering/fod6dLHD">soldering</a> through the use of a higher temperature and much more closely fitted parts. The principle of joining with filler metal is the same, but solder has a specific composition and lower melting point allowing work on delicate components such as electronics with minimal metallurgic reaction. The joints from soldering are weaker. 
Brazing joins the same or different metals with considerable strength.

Brazing open-in-new

Brazing