What is welding process and how many types of welding

Hello guys welcome to all today we will discuss most important topic that is Welding, in this topic we will  know What is welding process and how many types of welding.


what is welding process and how many types of welding


Welding is mostly used in Industrial area or fabrication yard where make new design of product to joining similar or dissimilar metal.

Welding, is an art of Joining the materials.
It is a type of fabrication process which joins the materials, normally metals or thermoplastics.

Welding should always be done by experienced and skilled welders, failing which the chances of welding defects increases.

In this topic, we will study about the different types of welding in production work.

so friends let's to know What is welding process and how many types of welding.

Welding process definition

In welding Process, joining of material like metal or thermoplastics pieces is done by increasing their temperature to the range of its fusion temperature so that, they form a pool of molten metal and after then cools to form the strongest joint.

Welding process provide permanent joint & its joining strength is much better than as compare to Soldering and Brazing.

Types of Welding

Welding can be divided into following basis
  • On the basis of the materials to be welded
  • On the basis of the pressure applied for welding

On the basis of the materials to be welded

On the basis of the materials to be welded, welding can be further divided into two types
  • Homogeneous Welding
  • Heterogeneous Welding

Homogeneous Welding

In this joining process, two similar metal parts are jointed either by using filler rod and no pressure is applied during the welding process.

Eg, welding of mild steel part.

Heterogeneous Welding

In this joining process, two dissimilar metal parts are joined by using the filler metal.

The filler metal is soluble in both the parent metal.

The filler metal is less than that of metal parts to be joined such that Its melting point is less than the parent metals.

On the basis of the pressure applied for welding

On the basis of the pressure applied for welding, types of welding are
  • Pressure or Plastic Welding
  • Non-pressure or Fusion Welding

Pressure or Plastic Welding

In this welding process, the surfaces which are to be weld is firstly heated up to their molten stage and then they are joined by applying pressure.

Non-pressure or Fusion Welding

In this process, the surfaces which are to be weld are kept together and heated by a heating source (such as flame or electric arc) , till they reach to the molten stage. In addition to this, a filler metal is used.

I think from above definition you all well understand what is welding process now from the table we easily understand how many types of welding using Pressure and Non Pressure Welding

Types of Pressure and Non Pressure Welding

What is welding process and how many types of welding
Types of Pressure and Non-Pressure welding

Brief Description of Welding Processes

From the above Types of welding some welding processes are given below
  • Arc Welding 
  • Gas Welding
  • Solid State Welding
  • Resistance Welding
  • Thermit Welding
  • Electron Beam Welding (EBW)

Arc Welding

Arc welding is a welding process in which fusion occurs by heating with an electric arc. 

Most often, arc welding is performed without pressure.

There are following types of arc welding
  • Manual Metallic Arc Welding
  • Submerged Arc Welding
  • Tungsten Inert Gas (TIG) Welding
  • Metal Inert Gas (MIG) Arc Welding
  • Plasma Arc Welding (PAW)
  • Atomic Hydrogen Welding (AHW)
  • Carbon Arc Welding (CAW)

Manual Metallic Arc Welding

When the welding is done by hand with flux coated electrode, then the welding is known as manual metallic arc welding. 

It's another name is shield metal arc welding.

Submerged Arc Welding

It is one of the arc welding processes where in coalescences(fusion) is produced by heating and an electric arc is set up between the bare electrode (copper coated) and workpiece under a blanket of granular flux metal electrode, continuously feed and act as a filler metal.

Tungsten Inert Gas (TIG) Welding

Tungsten Inert Gas welding process is also called as gas tungsten arc welding. 

It is also one of the types of an arc welding process that uses a non-consumable tungsten electrode to produce the welding process and join the metal.

In this process during welding weld area is saved from atmospheric contamination by an inert shielding gas like argon or helium.

Metal Inert Gas (MIG) Arc Welding

Metal inert gas welding another name is metal gas arc welding.

Metal inert gas welding process, is a type of the tungsten inert gas welding process.

This process is used where the more precision required and consumable electrode is used in this process.

In this welding process, the electric arc forms between wire electrode and workpiece which heats the workpiece, causing them to melt and join after solidification.

Plasma Arc Welding (PAW)

Plasma arc welding is an arc welding process and plasma refers to an ionised state of matter. 

In PAW, the electrode is located within the body of the torch and separated by an envelope of shielding gas.

Atomic Hydrogen Welding (AHW)

Atomic hydrogen welding is also a type of an arc welding process that uses an arc between the two metals.

Carbon Arc Welding (CAW)

Carbon arc welding is a type of welding process, which produces heat by joining the metal. 

In this process carbon (graphite) electrode are used.

Electro Slag Welding (ESW)

Electro slag welding is a highly productive type of welding process. 

This process is generally used for welding a thick material only in a vertical or nearest to vertical position.

Gas Welding

Gas welding is a process of melting and joining metal parts by means of a gas flame.

In a gas welding, three types of gas welding flames are used like neutral, carburizing, and oxidizing flame.

There are following types of gas welding given below
  • High Pressure Gas Welding
  • Low Pressure Gas Welding

High Pressure Gas Welding

High pressure welding consists the pressure of acetylene gas that means 15 kg per square centimetre. 

It is performed in industries. This process of welding is known as high pressure gas welding.

Low Pressure Gas Welding

This process consists a pressure of acetylene gas that means, 1 kg per square centimetre generated by a small gas generator in a domestic environment. 

This process of welding is known as low pressure gas welding.

Solid State Welding

Solid state welding is one of the important types of welding process, in which the heat required for welding purpose is produced by rubbing or by applying hammering operation on two workpieces.  

In solid state, welding, pressure is applied to form the weld joint.

Solid state of welding can be divided into following categories
  • Forge Welding
  • Friction Welding
  • Ultrasonic Welding
  • Laser Beam Welding (LBW)

Forge Welding

Forge welding is a type of solid state welding process in which the metal parts to be joined when heated the metal parts up to metal's hot working temperature and then forged together by using of the hammer or other.  

This welding process specially applied in a Forging Process

Friction Welding

Friction welding is also a type of solid state welding process in which heat is produced through frictional heat combined with pressure.

In this process heat is generated through the friction between the two metals or metal parts surfaces, normally by rotating of one part relative to other.

Ultrasonic Welding

In ultrasonic welding, high frequency ultrasonic acoustic vibrations are used to weld the workpieces.

It is used to weld the two dissimilar metals such as aluminium to steel, aluminium to tungsten, nickel to brass, etc.

Laser Beam Welding (LBW)

Laser beam welding is a welding technique used to join multiple metal parts using a laser beam.

The beam provides a concentrated source of heat, allowing narrow and deep welds to be made at high welding speeds. 

This process is often used in large volumes, for example in the automotive industry.

Resistance Welding

Resistance welding is a type of pressure welding process.

The basic working principle of resistance welding depends upon

H = I^2RT
where,
H = heat generated
T = time
R = resistance
I = current required

Thermit Welding

Thermit welding is a welding process in which no external heat source is required for melting the workpiece to form the joint.

Electron Beam Welding (EBW)

Electron beam welding is a type of  fusion welding process, in which a  high velocity beam electrons is applied as a force to join the two materials like similar or dissimilar metal forming a joint on solidification.


Welding Joint

The various types of joint prepared during the welding process are as follows
  • Butt Joint
  • Lap Joint
  • T Joint
  • Edge Joint
  • Corner Joint

Butt Joint

In the butt joint, two members are joined by simple butting them together. 

Single side welding is done up to thickness of 3mm, for the thickness of 3 to 5 mm welding is done on both sides of the workpiece.

Lap Joint

When the joint is formed by overlapping the two surfaces, then it is known as lap joint.

T Joint

When one plate is joined at an angle of 90° to the other plate, then the joint is known as T joint.

Edge Joint

This joint likes a butt joint. The joint is made by hanging the edges of their sheets.

Corner Joint

When the edge of the sheets are held together and jointed, then this type of joints is known as corner joint.

Welding Defects

Welding defects are of two types, which are given following
  • External Defect
  • Internal Defect

External Defect

1. Cracks
2. Uneven bead
3. Spatters
4. Craters
5. Under cut
6. Distorted joints
7. Surface porosing
8. Lack of filler metal
9. Over heating
10.Excess of penetration

Internal Defects

1. Blow holes or porosity
2. Internal cracks
3. Slag inclusion
4. Lack of fusion
5. Incomplete penetration
6. Harder and brittle joints


So,
I hope you all clearly understand What is welding Process and how many types of welding.
If any query you free to all comment in a comment box.

Thank You

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