Engineering Workshop Welding Concepts

Brazing and Soldering Process:Mechanism,Filler rod,Applications

Brazing and Soldering Process: In all the non-fusion welding processes, when the liquid molten metal is poured at the joint, it gets wet and Solidifies. During the process of Solidification, the atoms present on the surface of filler rod are sharing the energy with atoms present on the surface of parent material and thereby it produces the joint.

When the surface atoms are sharing the energy producing the joint it is called Surface Alloy Joining.

Brazing and Soldering Process:Mechanism,Filler rod,Applications
Brazing and Soldering Process: Mechanism, Filler rod, Applications

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1.Brazing Process

2.Working Principle of Brazing Process

3.Applications of Brazing Process

4.Soldering Process

5.Working Principle of Soldering Process

6.Applications of Soldering Process

Detailed Explanation of Brazing and Soldering Process:

1.Brazing Process:

It is a process of joining similar or dissimilar metals by means of filler material. The filler material is called as Spelter and the filler material is made up of Copper alloy.

Spelter+Borax+Water = Paste

A mixture of Spelter and Borax with Water is used as a paste and is applied to the metal parts at the joints.

2.Working Principle of Brazing Process:

First, you need to take two workpieces to join them by the process of brazing. As in the case of soldering, we had used soldering gun and filler material for the formation of joint whereas in Brazing process, a paste is used which is the mixture of (Spelter+Borax+Water) and is to be applied on to the work region.

Later, the applied material has to be heated so that it can melt and form as a layer in between two workpieces. Here, Oxy-Acetylene gas welding is used to heat the mixture for the formation of joints. The workpiece has to be cleaned after cooling so that the impurities cannot stick on the workpiece.

Points to be noted:

1. The mechanism of the joint is Wetting and Surface Alloying.

  • Joining of two metals without preparing any joint is called as brazing operation.

2. The temperature of the joint must be greater than the melting point of metals. So here in the case of brazing, the temperature of the joint must be greater than 450-degree centigrade.

3.Type of Joint: Permanent

4.Load bearing capability: High

5.Filler Rod: Copper(Cu) Alloys

  • Most commonly used filler rod materials in the brazing and braze welding are copper alloys therefore for melting of the filler rod material, Joint must be heated at a temperature greater than 450-degree centigrade.
  • As there is no joint prepared, the flow of molten metal into the joint is taking place due to capillary action.
  • Due to this, the molten metal of filler rod which is having the highest capillary action will be used as filler rod material.
  • Out of the different metals, the molten metals copper, zinc alloy is having the highest capillary action. hence, it is used as a filler rod in the brazing operation.

3.Applications of Brazing Process:

  • Brazing is used for fastening of pipe fittings, carbide tips on tools, heat exchangers, electrical parts, radiators, axles, etc.
  • It can join cast metals to wrought metals, dissimilar metals, porous metal components etc.
  • It is used to join parts of the bicycle such as frame and rims.

4.Soldering Process:

It is a process of joining similar or dissimilar metals by means of filler material. The filler material is called as Solder and the filler material is made up of Lead-Tin alloy.

During soldering, there is a need for flux which is made up of Zinc Chloride, Ammonium Chloride, and resin is mixed with them.

What is the duty of Flux? Click Here

  1. The mechanism of the joint is Wetting and Surface Alloying.
  2. Type of Joint: Temporary.
  3. Load bearing capability: less than Brazing
  4. The temperature of the joint must be less than the melting point of metals. So here in the case of soldering, the temperature of the joint must be less than 450-degree centigrade.
  5. Filler Rod:(50% lead & 50% Tin Alloy)

When the (50% lead & 50% Tin Alloy) is to be heated to a temperature greater than 450-degree centigrade, the tin present in the lead & Tin alloy starts evaporating. Hence the temperature of the joint must be <450 Degree centigrade.

5.Working Principle of Soldering Process:

First, the Soldering gun is to be heated up to the desired temperature. Now, the filler metal has to be in contact with the soldering gun with which the filler metal melts and deposits on the work region.

The melted filler metal enters into the work region by the action of capillarity and after cooling, the joint is formed.

6.Applications of Soldering Process:

Mostly used to solder the wires on the Printed Circuit Boards(PCB).

This is the complete explanation of Brazing and Welding operations in a detailed way.

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