Hello, friends today I will talk about Soldering and Brazing and also we will know What is Difference between Soldering and Brazing.
Soldering and Brazing both are joining two or more similar and dissimilar metals.
Like welding process but soldering and brazing joining strength is less as compared to welding.
Soldering and brazing both are mostly used in small industries.
Soldering is a semi-permanent fastener whereas brazing is a permanent fastener.
So there is a common Difference between Soldering and Brazing which will we know in detail.
To know the difference between soldering and brazing, first of all, we have to know about soldering and brazing very well, only then we will be able to understand the difference between them well.
So let's start to know,
What is Soldering?
The soldering process is done by fusible alloy which is known as a solder.
Solder is applied in a molten state on the metal and after solidification, it forms the joint.
One of the most advantages of soldering that is there are no changes in mechanical properties when joining any similar or dissimilar metal.
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| Soldering |
What is Solder?
Solder is nothing but it is a mixture of tin and lead whose melting point temperature is around 235°C and 350°C, respectively.
But when tin and lead are mixed then the melting point of the mixture is reduced to 183°C.
Depending on the melting points, the solder is classified as:
- Hard Solder
- Soft Solder
Hard Solder
Hard solder is used for joining large metal pieces, thick wires, and also used joining cables of copper, iron brass and so more.
Hard solder melting point is so high in comparison to other types of solder.
Hard solder can be classified into two types
- Spelter Solder
- Silver Solder
Spelter Solder
It is made in three compositions and used according to the requirement.
- Copper = 50 %, Zinc = 50 %
- Copper = 67 %, Zinc = 33 %
- Copper = 50 %, Zinc = 37 %, Tin = 13 %
Silver Solder
Silver solder is used for joining precious types of metal like gold, silver, german silver, and many more.
Silver solder's melting point is less as compared to spelter solder.
Its composition for joining different metals is:
- Copper = 33 %, Silver = 67 % (This composition is used to solder silver jewelry)
- Copper = 20 %, Silver = 10 %, Gold = 70 % (This composition is used to solder gold jewelry)
- Copper = 20 %, Silver = 70 %, Zinc = 10 % (This composition is used to solder ornamental jewelry)
- Copper = 35 %, Zinc = 55 %, Nickel = 10 % (This composition is used to soldering for German silver)
Soft Solder
Soft solder melting point is less as compared to silver solder.
Soft solder is a combination of lead and tin alloy.
In the soft solder melting point is inversely proportional to the amount of tin in the solder.
Flux
Flux is normally available in the form of powder, paste, and liquid, It protects the joining surface from oxidization and also cleans the surface.
Methods of Soldering
According to the method of heating, soldering is classified as:
- Soldering iron method
- Soldering torch method
- Dip and wave method
- Induction method
- Furnace and hot plate method
- Ultrasonic method
- Resistance and hot plate method
- Spray method
- Condensation method
In the above methods, only the first two methods are mostly used.
So, here we will discuss these two methods.
Soldering Iron Method
It is one of the oldest methods of soldering. It is a type of hand tool used for the purpose of soldering.
In the iron method, process heat is supplied such that to flow between the workpiece join similar or dissimilar metal.
A soldering iron is composed of a heated metal tip, a stem, and an insulated handle.
The soldering iron method is similar to smith forging the only difference is soldering is joining similar or dissimilar metal while forging is deforming the metal in a particular shape.
Soldering Torch Method
The method of soldering in which heating is done by using heat energy provided by a gas torch is known as the soldering torch method.
What is Brazing?
In the brazing process, the filler metal is heated such that no contact with the atmosphere, usually a flux, when it's melting above melting point temperature.
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| Brazing |
What is Spelter or Brazing Alloy?
The filler metal is used for brazing which is called a spelter or brazing alloy or also called solid solder.
There are different varieties of alloys is used as filler metal for brazing.
The variety of alloys that are used in brazing that’s depends on the method of application used.
Methods of Brazing
The different methods used for the brazing process are discussed below
These processes are almost the same as soldering:
- Blow Pipe Brazing
- Furnace Brazing
- Torch Brazing
- Vacuum Brazing
- Induction Brazing
- Dip Brazing
- Resistance Brazing
Blow Pipe Brazing
This method is mainly used by the goldsmith in the brazing of ornaments.
It is used for small size job joints.
Furnace Brazing
In this method, furnaces are used to heat the workpiece to be joined by brazing operation.
The internal stress developed in a joint by this method is minimum.
Because during heating of workpiece its behave like a heat treatment process that’s why some mechanical properties changes during brazing.
Torch Brazing
In the torch brazing method, flux is used to a surface, and also a focusing flame torch is used which is against the workpiece at the joint.
A filler metal wire or rod is added to the joint.
Torch uses a mixture of two gases, oxygen, and acetylene, as a fuel in gas welding.
Vacuum Brazing
It is a special type of furnace brazing, in which metal is prevented from oxidation, by creating a vacuum around surroundings.
Induction Brazing
In this method, electricity is used for brazing.
This method uses the electrical resistance of the workpiece to generate heat.
In the induction brazing method which parts are to be joined firstly, it's pre-loaded with filler metal and then placed in a high-frequency AC field.
Frequencies range is used up to from 5 to 5000 kHz.
Dip Brazing
In dip brazing, the parts which have to be joined are dipped inside molten filler metal after applying flux on it.
Resistance Brazing
In resistance welding, the workpieces are directly connected to electrical current rather than induction of the electric current line.
Heat to melt the filler metal is generated by the resistance of the flow of electric current through the joint to be made.
Comparison of Soldering and Brazing
All the two processes Soldering and brazing have similarities in that these are bonding processes.
In all the two processes filler metal, flux, and heat energy are used.
But the strength of the bond and its durability and other feature as different.
So, let us compare soldering and brazing.
Difference Between Soldering and Brazing
| Soldering | Brazing |
|---|---|
| It is used in electrical industries to join capacitors, resistors, wires, etc in electronic plates. | It is used in mechanical industries, automobile industries, etc. To join different metals. |
| Soldering occurs at temperatures below 840°F (450°C). | Brazing occurs at a temperature above 840°F (450°C). |
| These joints are weaker than brazing joints. | It forms a stronger joint. |
| The filler material is an alloy of lead (Pb) and tin (Sn). Which is known as solder. | The filler material is an alloy of copper (Cu) and zinc (Zn), Cu and silver (Ag), Cu, and aluminum known as a spelter. |
| It does not require special training for soldering. | It needs special training. |
| It is a cheap process. | It is a costly process. |
| Soldering does not require the base metal to be preheated. | This process needs preheating of base metal. |
| The flux used in soldering is zinc chloride (ZnCl2) and HCl. | The flux used is borax and boric acid. |
| During soldering no changes in mechanical properties of metal after joining. | During brazing, it has almost negligible changes. |
| As a heat source, electric resistance heating (soldering gun) is used. | As a heat source, commonly used Oxy-H2 flame, oxy-acetylene flame, induction heating, furnace, etc. |
| Joint preparation is not required. | Sometimes joint preparation is required. |
| Electrical wire can be joined by soldering. | Electrical wire can not be joined with brazing. It is used to joining of any metal, arrested leakage in automobiles, etc. |
Thank You.
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