AWS is committed to helping to educate and put out content for different users of brazing and soldering alloys. This includes the brazing, and soldering handbooks, and other specifications for Brazing and Soldering. To the right in the white box are the quick links to further information for, specifications, training, and Q&A that is run by the different AWS C3 committees, A5H, and the Brazing and Soldering Manufacturers Committee.

What is brazing?

Definition/description of brazing

  • Brazing is the joining process that relies on the melting, flow, and solidification of a brazing filler metal between the closely fitted faying surfaces of the joint by capillary action, to form a leak-tight seal, a strong structural bond, or both between materials. The components being joined undergo no melting
  • Brazing is referred to as a joining processes performed using a filler metal having a liquidus above 840°F (450°C).

What is soldering?

Definition/description of soldering

  • Soldering is a process whereby the filler metal (solder alloy) has a liquidus temperature below 450°C (842°F).

Advantages of soldering

  • Low liquidus temperatures allow for correspondingly low process temperature (typically Δ20°C/Δ36°F above the liquidus temperature) that minimize heat damage to the base material(s).
  • Solder joints can be “unsoldered” and resoldered to repair defects.

General requirements

  • Molten solder must wet-and-spread on the base material (faying) surface(s).
  • Wetting is the formation of a metallurgical bond between the solder and the base material.
  • Fluxes are an integral facet of the soldering process.
  • Surface finishes optimize wetting-and-spreading activity on hard-to-solder base materials such as aluminum, stainless steel, etc.
  • Solder filler metal nearly always have a lower mechanical strength than the base material.

Soldering Applications

  • Electronics applications: solder alloys are used in the assembly of electronic products that include individual device construction, printed circuit boards, and connectors. 
  • Structural applications: soldering is used to attach of conduit (pipes) together for a variety of application (potable water, chemicals, cryogenic liquids and gases) as well as for gutters and the fabrication of common light-duty products: e.g., cooking utensils, kitchen equipment and hand tools.

The following Industries use brazing and soldering in their everyday processes.

  • Aerospace
  • Automotive
  • Electronics
  • HVAC / Refrigeration
  • Military applications
  • Oil and Gas
  • Construction
  • Medical



Fig. 1: Cross Section of Brazed Joint
Fig. 2: Steel Joint with Filler Metal Added
Fig. 3: Illustration of Copper-to-Copper Brazed or Soldered Joint
Fig. 4: Wetting and spreading in the soldering process
Fig. 5: General solder joint microstructure
Fig. 6: Electronic applications
Fig. 7: Structural applications



The Brazing & Soldering Manufacturers Committee (BSMC) helps to direct content on For more info on the Brazing & Soldering Manufacturers Committee page.