What are soldering and brazing
Soldering of Aluminium
Brazing of Aluminium
Aluminium soldered brazed products
Solerabilty of aluminium alloys
Brazeabilty of aluminium alloys
Filler metal used in brazing Aluminium
Soldering brazing Aluminium to other metals
Is soldering or brazing more suitable
Joining process using
a heating method and
a filler metal
the base materials .
Filler metal has a
liquidus below 800 F .
Joint strength ↓
Filler metal has a
liquidus above 800 F .
Join strength ↑
Joining dissimilar metals and non-metals
allows much tighter control over tolerances
Low temperature compared to welding
less thermal distortion
Speed of joining
Less manual skills
the lack of joint strength .
damaged under high
temperature condition .
Low temperature soldering
390 F → 650 F
High temperature soldering
250 F → 400 F below
Al-alloys melting point
Close temperature control is required .
The brazing temperature should preferably be
70 F below melting point of Al
In condition of accurately
controlled of temperature
it can be done at 10 F
Most brazing is done between
1020 →1180 F
• Aluminium products joined by
Almost all aluminium alloys can be soldered
Alloys containing more than 1% Mg can not be
soldered satisfactorily . (5xxx _ 6xxx)
(intergranular penetration )
Alloys containing more than (5%) Si can not be
soldered (4xxx 6xxx)
1xxx , 3xxx , 6xxx and low-Mg members of
5xxx are most successfully brazed alloys
2xxx , 7xxx not normally brazed because of low
melting temperature .
Melting between 300 F → 500 F
Composed of Tin, lead, zinc, cadmium
And small amount of Al ,copper ,Nickel
Good low-temperature solder used in
aluminium soldering is :
The eutectic alloy containing :
91%SN , 9%ZN
Melts at 400 F
2. Intermediate-temperature solder
Melts at 500 F → 700 F
Contains : Tin ,Zinc < 30% → 70%>
and Small amount of copper, lead and silver
3.High-temperature solders :
Melts between 700 → 800 F .
Containing from 90% → 100% Zn and from
2% → 10% Al .
Strongest and superior corrosion resistance .
Powder , paste or wire
Commercial filler metal alloy using in
Al-brazing are :
To reduce brazing temperature the
following alloy elements were added :
1. copper → intermetallic compound AL-Cu
2. Germanium → expensive
3. Beryllium → healthy hazards
Aluminium brazing fluxes
contain chlorides and fluorides
Aluminium soldering fluxes
1.Organic : melts 400 → 525 F
Contain zinc fluoride or zinc chloride
2. Non-organic : melts 540 → 720 F
Common in Al assemblies
manual or automatic ,
No limitation on thickness
High production rate
↑ production rate
the best method for AL
Any solderable material can be soldered to
tungsten , are difficult to
solder to Aluminium .
Al can be brazed to many other metals
Al to copper : is difficult to braze because of
low melting temperature (1018 F) of Al-copper
eutectic composition .
Al to steel : possible (dip brazing)
Al to magnesium : easy but brittle joint .
That depends on :
1. Strength requirements
brazed joints can be 3 – 10
the strength of soldered joints
2. Corrosion resistance
solders are less corrosion resistance