Download BRAZING AND BRAZE WELDING Fluxes

Teknologi Dan Rekayasa
BRAZING AND BRAZE WELDING
BRAZING AND BRAZE WELDING
 OBJECTIVE :
After studying this lesson, the students
can be explain the brazing and braze
welding method.
Teknologi dan Rekayasa
BRAZING AND BRAZE WELDING
 Understanding :
 According to American Welding Society
(AWS) brazing is defined as a group of
welding processes where coalescence is
produced
by
heating
to
suitable
temperatures above 800° F and by using a
nonferrous filler metal having a melting
point below that of the base metals.
 The filler metal is distributed between the
closely fitted surfaces of the joint by
capillary action.
Teknologi dan Rekayasa
BRAZING AND BRAZE WELDING

Brazing requirement :
The success of any brazing operation depends
on joints having relatively small clearances
and surfaces that are free of oxide and other
contaminants.
Teknologi dan Rekayasa
BRAZING AND BRAZE WELDING
• Types of joint for brazing :
The two basic joint for brazing are the lap and
butt. (Tee and corner joints are considered as
butt joints).
Fig.1. Butt Joint
Fig.2. Lap Joint
Teknologi dan Rekayasa
BRAZING AND BRAZE WELDING
Fig. 3. Typical Joint for brazing
Teknologi dan Rekayasa
BRAZING AND BRAZE WELDING
Brazing filler metals :
A brazing filler metal should meet following
requirements :
1. Sufficient fluidity so the metal will flow evenly
by capillary attraction.
2. Good melting action to form a sound
metallurgical bond.
3. Melting point consistent with the type of metal
to be joined.
Brazing filler metals fall into seven groups : silver,
aluminium-silicon,
copper-phosphorus,
gold,
copper and copper-zinc, magnesium and nickel.
Teknologi dan Rekayasa
BRAZING AND BRAZE WELDING

Fluxes :
Any form of oxide on the surface of a metal will
inhibit a uniform flow of the brazing metals.
Accordingly a flux some kind is necessary to
eliminate the oxide.
The common commercial fluxes are in paste,
liquid, or powder form
Fluxes have as their main ingredient borates,
fused borax, boricacid, fluorides, chlorides, and
fluborates.
Teknologi dan Rekayasa
BRAZING AND BRAZE WELDING

BRAZE WELDING :
Braze welding is slightly different from regular
brazing.
Braze welding is carried out much as fusion
welding except that the base metal is not
melted.
The base metal is brought up to its tinning
temperature and then a bead is deposited over
the seam with a filler rod.
Teknologi dan Rekayasa
BRAZING AND BRAZE WELDING


Bronze welding is a typical braze welding
operation. This technique is frequently used for
joining or repairing such metals as cast iron,
malleable castings, copper, brass, and various
dissimilar metals.
The bronze filler rod which is applied to the
seam consist of copper and zinc with small
quantities of tin, iron, manganese, and silicon.
Teknologi dan Rekayasa
Teknologi dan Rekayasa