BRAZING AND BRAZE WELDING
Upon completion of this chapter; you should be able to do the following:
Identify the tools and equipment used in silver brazing.
Describe the techniques used in braze welding and silver brazing, and define the
different types of filler metals available.
Explain the necessity of using fluxes, the different types of flux available, and the
correct procedures to use in applying fluxes.
Describe the procedures for hydrostatically testing silver-brazed joints.
Describe hard surfacing and identify the materials and techniques used in hard
Describe the uses of powdered metals and the correct procedures in the application
of powdered metals.
You will often see the word tinning used in
connection with silver brazing and braze welding. The
This chapter will cover silver brazing, braze
surface of the base metal is said to be tinned when a very
welding, surfacing, powdered metal flame spraying,
thin continuous film of tiller metal precedes the main
and soldering processes. The various associated
part of the filler metal. Tinning can only occur on metal
equipment will also be discussed along with its safe
that has been cleaned, fluxed, and heated to the correct
operation. You will find that silver brazing and braze
temperature. If tinning does not occur, the main part of
welding are two welding processes that you will use
the filler metal will not adhere to the base metal. Tinning
quite often. There are a number of ways to silver braze,
will be discussed later in this chapter.
but it is done most often with an oxyacetylene torch.
Braze welding and silver brazing are similar in
many ways, but they are two different welding
processes. In silver brazing, a silver-base alloy is used
Silver brazing is a process where coalescence is
as a filler metal and the base metal is NEVER melted.
produced by heating with a gas flame. It uses a silver
alloy filler metal with a melting point above 800°F, but
The filler metal is distributed throughout the joint by
below the melting point of the base metal. The filler
capillary attraction. In braze welding, a copper-base
metal is distributed in the joint by capillary attraction.
alloy is used as a filler metal and it is deposited in groove
and fillet welds exactly at the points where it is to be
Let's consider some everyday examples of the
used. Limited base metal fusion may also occur in braze
process used in silver brazing. When you use a blotter,
welding; capillary attraction is not a factor.
the ink is drawn up into the blotter by capillary