Soldering and brazing are joining processes that use a filler metal to bond materials without melting them. Soldering uses filler metals with melting points below 800°F to produce weaker but lower cost joints, while brazing uses higher melting point filler metals above 800°F, producing stronger but more expensive joints. Brazing can join dissimilar metals and non-metals and offers benefits like tighter tolerances, less thermal distortion, and easier alignment compared to welding. Most aluminum alloys can be soldered or brazed, though alloys with over 1% magnesium solder poorly and over 5% silicon do not solder well. The choice between soldering and brazing depends on the required strength, corrosion resistance

2.  What are soldering and brazing
 Soldering of Aluminium
 Brazing of Aluminium
 Aluminium soldered brazed products
 Solerabilty of aluminium alloys
 Brazeabilty of aluminium alloys
 Solders
 Filler metal used in brazing Aluminium
 Fluxes
 Soldering methods
 Brazing methods
 Soldering brazing Aluminium to other metals
 Is soldering or brazing more suitable

3.  Joining process using
a heating method and
a filler metal
without melting
the base materials .

4.  SOLDERING  BRAZING
 Filler metal has a
liquidus below 800 F .
 Joint strength ↓
 cost ↓
 resistance to
corrosion ↓.
 Filler metal has a
liquidus above 800 F .
 Join strength ↑
 cost ↑
 resistance to
corrosion ↑

5.  Joining dissimilar metals and non-metals
 allows much tighter control over tolerances
 Low temperature compared to welding
 less thermal distortion
 clean joint
 Speed of joining
 Easy realignment
 Less manual skills

6.  the lack of joint strength .
 joint colour
 damaged under high
temperature condition .

7.  Active fluxes
 Low temperature soldering
390 F → 650 F
 High temperature soldering
250 F → 400 F below
Al-alloys melting point

8.  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

9. • Aluminium products joined by
brazing/soldering

10. • Aluminium frames

12.  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)

13.  1xxx , 3xxx , 6xxx and low-Mg members of
5xxx are most successfully brazed alloys
 2xxx , 7xxx not normally brazed because of low
melting temperature .

14. 1.Low-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

15. 2. Intermediate-temperature solder
 Melts at 500 F → 700 F
 Contains : Tin ,Zinc < 30% → 70%>
and Small amount of copper, lead and silver
 Stronger joints

16. 3.High-temperature solders :
 Melts between 700 → 800 F .
 Containing from 90% → 100% Zn and from
2% → 10% Al .
 Strongest and superior corrosion resistance .

17.  Powder , paste or wire
 Commercial filler metal alloy using in
Al-brazing are :
Aluminium-silicon alloys
containing
7%→12 Si

18.  To reduce brazing temperature the
following alloy elements were added :
1. copper → intermetallic compound AL-Cu
2. Germanium → expensive
3. Beryllium → healthy hazards

19.  Flux function
 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

20.  Iron soldering
Common in Al assemblies
 Furnace soldering
Large assemblies
 Abrasion soldering
no flux
 Induction soldering
rapid

21.  Flame soldering
manual or automatic ,
No limitation on thickness
 Dip soldering
High production rate

22.  Torch brazing
economical
 Furnace brazing
↑ production rate
 Dip brazing
the best method for AL

23.  Any solderable material can be soldered to
Aluminium .
 Magnesium, titanium,
tungsten , are difficult to
solder to Aluminium .

24.  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 .

25. 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
3. Temperature
4. Cost

26. Thank you