• Brazing is a metal-joining process.
• Brazing is when a filler metal or alloy is heated to its
melting temperature above 450 °C.
• It is then distributed in liquid form between two or more
close-fitting parts by capillary action.
• The filler metal is then brought slightly above its melting
• It then interacts with a thin layer of the base metal
(known as wetting) and is then cooled quickly.
• This forms a sealed joint.
• Brazed joints are generally stronger than the individual
filler metals that have been used to make them.
• This is because of the geometry of the joint and the
metallurgical bonding that occurs.
• Soldering is a process in which two or more metals are joined
together by melting and flowing a filler metal into the joint,
the filler metal having a relatively low melting point. Soft
soldering is characterized by the melting point of the filler
metal, which is below 400 °C.
• The filler metal used in the process is called solder.
• Soldering is distinguished from brazing as the filler metal used
has a lower melting point.
• Soldering is normally done by melting the solder with a
soldering iron and applying it to the two metals that are going
to be joined together.
Advantages of brazing
It's easy to learn.
You can join virtually any dissimilar metals.
The bond line can be very neat in appearance.
Joint strength is strong enough for most nonheavy-duty use applications
Disadvantages of brazing
• A badly brazed joint looks similar to a good joint, and can
have a VERY low strength.
• The metal used to bond the two parts may be different in
color than the parts being bonded. This may or may not
be a problem.
• Long-term effects of dissimilar metals in constant contact
may need to be examined for special applications.
• Since the filler material (typically bronze) melts at a
relatively low temperature, brazed parts may not be put
in an environment which exceeds the melting point of the
Advantages of soldering
• Low power is required;
• Low process temperature;
• No thermal distortions and residual stresses in
the joint parts;
• Microstructure is not affected by heat;
• Easily automated process;
• Dissimilar materials may be joined;
• High variety of materials may be joined;
• Thin wall parts may be joined;
• Moderate skill of the operator is required.
Disadvantages of soldering
• Disadvantages of soldering
• Careful removal of the flux residuals is
required in order to prevent corrosion;
• Large sections cannot be joined;
• Fluxes may contain toxic components;
• Soldering joints can not be used in high
• Low strength of joints.