What is Brazed Joint? (See the 5 Types of Brazing Joints)

What is brazed joint? 
Brazed joint is a joint of two similar or dissimilar metals which is made by using a fusible alloy called “spelter”.

Brazing is similar to the soldering process, but the only difference is that brazing uses spelter instead of solder.

Spelter refers to the alloy in which zinc is the main constituent. It is softer and has a lower melting point. Spelter also refers to zinc-copper alloy (i.e brass) which is used for brazing of metals.

Types of Brazing joints

brazing joints

There are 5 commonly used brazing joints for joining of metals.

  1. Butt joint
  2. Lap joint
  3. Corner joint
  4. Tee joint
  5. Scarf joint

Let’s see each type of brazed joints one by one.

#1) Butt joint

butt joint

As shown in the above diagram, the butting of two metal pieces are made against one another (without overlapping) and then they are brazed along the seam between them.

#2) Lap joint

lap joint

Lap joint is made by overlapping two pieces of metal and then the edge of the one metal piece is brazed with the surface of the other metal piece.

In lap joint, both the metal pieces are required to have a good surface contact with each other along the entire length.

#3) Corner joint

corner joint

Corner brazed joint is a type of brazing joint in which one metal piece is at the right angle to the other metal piece (and this way both the metal pieces form the corner).

#4) Tee joint

tee joint

Tee brazed joint is a type of brazing joint in which both the metal pieces form the “T-shape”.

In the T joint, the brazing is done on both the sides of the perpendicular metal piece.

#5) Scarf joint

scarf joint

Scarf joints are made by cutting the surface at some angle and then they are overlapped to get the brazing done.

Lap joint and butt joint are generally used in sheet metal working while the scarf type of joints are used for brazing of rods or pipes.

External links:
Brazing image credits: Cyfac, CC BY-SA 3.0, via Wikimedia Commons
Scarf joint: Image by SilentC at the English-language Wikipedia, CC BY-SA 3.0, via Wikimedia Commons

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