Engineering Workshop Welding Concepts

Welding-Definition,Applications,Methods of Joining,Weld joints,Coated Electrode

Welding Definition: Welding is a process of joining two or more similar or dissimilar metals with or without the application of heat, with or without the application of pressure, with or without the application of filler material.

  • The welding is widely used as a fabrication of joining two or more parts and repairing process in industries.

Applications:

Some of the applications of welding include the fabrication of automobile bodies, ships, pressure vessels, welded pipes, bridges,  sealing of explosives, etc.

Welding-Definition,Applications,Methods of Joining,Weld joints,Coated Electrode
Welding-Definition, Applications, Methods of Joining, Weld’s joints, Coated Electrode

Various Methods of Joining:

There are various methods for joining two plates/sheets etc and are as follows.

1.   Welding

2.   Riveting

3.   Nut and Bolts or Screws

4.   Soldering

5.   Brazing

The explanation of the above terms is as follows.

1.Welding

It is already explained above.

2.Riveting

  • Rivets are used to join metals, plastics, Sheet metals, and plywood.
  • It is a Permanent Joint.
  • First, holes are made on the surface of the sheet/plate and the rivets are inserted between the two such sheets so that it can form a joint.

Ex: Bus Top is enclosed by the shell. The shell is formed by joining of the individual sheets by Rivets.

Types of Rivets:

  1. Snap Head Rivet
  2. Pan Head Rivet
  3. Countersunk Head Rivet
  4. Flat Head Rivet
  5. Pop Head Rivet

3. Nuts and Bolts or Screws

Screws are generally used in the household applications to fix anybody to the wall or Nails to the Wood.

Nuts and Bolts are generally used in Industrial Applications where the machine parts are joined by the Nuts and Bolts.

4.Soldering:

Soldering is a type of brazing which works at lower temperatures.

  • Soft solderingis used to make permanent joints and is normally used to join components to electronic circuit boards.
  • Hard soldering is applicable for stronger joints.

5.Brazing

  • Brazing is a process of joining materials by melting a filler metal between the components.
  • The filler metals must have a lower melting point than that of the material being joined.
  • Brazing forms very strong and permanent joints.

Types of Welding Process:

Welding Processes has been classified based on Fusion, Non-Fusion, and Pressure Welding processes.

Detailed info on Types of welding Processes. CLICK HERE


Welding Joints or Weld Joints:

Weld Joint design is greatly influenced by:

  • The accessibility of the Weld Joint
  • Cost of repairing the joint
  • It’s adaptability for the product being designed or welded.
  • Type of loading, the weld is able to withstand.

The different types of welding Joints that are commonly used are shown in the above figure.

1.   Butt  Joint

2.   Corner Joint

3.   Edge Joint

4.   Lap Joint

5.   Tee Joint


Coated Electrode:

An electrode is a piece of wire or a rod of a metal or alloy, with or without coatings. An arc is set up between electrode and workpiece. Welding electrodes are classified into following types.

  1. Consumable Electrodes
  2. Coated Electrodes
  3. Bare Electrodes
  4. Carbon or Graphite Electrodes
  5. Tungsten Electrodes
  6. Non-consumable Electrodes

Coated Electrodes:

  • Coated electrodes have a flux coating which starts melting as soon as an electric arc is struck.
  • This coating on melting performs many functions like prevention of joint from atmospheric contamination, arc stabilizers etc.

Advantages of coatings given on the electrodes:

  • It can be de-oxidizes the melt.
  • It can absorb gases present in the weld pool.
  • It can form a slag layer over the weld bead.
  • It can stabilize the arc.
  • It can produce shielding gases like Hydrogen, carbon dioxide etc.
  • It can supply alloying elements to the weld bead for improving the mechanical properties.

This is the explanation of Welding-Definition, Applications, Methods of Joining, Weld joints, Coated Electrode in a detailed way.

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