The term welding is actually used to join metal parts together by the use of heat/pressure or both. It is an ancient technique that has also been used as a popular occupation in the modern era.

1. Welding-types, applications and invention
Welding is a process of union between two or more parts of materials
where it is united using heat/pressure or both.
Introduction
The welding’s types, applications, and invention
The term welding is actually used to join metal parts together by the use of
heat/pressure or both. It is an ancient technique that has also been used as a popular
occupation in the modern era.
It is a manufacturing activity wherein, heat and pressure, or both, are used to join two
parts permanently. Metal, wood, and thermoplastic, are joined together in this method.
Definition
A process whereby two or more parts are connected through heat/pressure or both. It is
used to weld all types of metals, thermoplastics,
Preface

2. Before proceeding let’s have a look, at a brief history of welding.
Welding technology is considered an ancient method of joining materials. It began to
use when human civilization was in the stone era. They found an element buried in clay
that was somewhat shiny and different. Humans started experiments with it, it was used
for ornaments, food utensils, and weapons.
Origin
Welding developed with the needs of human civilization and became popular as an art,
but with the development of human society, this technique also intensified and took the
form of modern science.
The method of joining metals together began around 4000 BC, in Egypt and its
surrounding areas. It began with copper and then expanded into bronze, silver, gold,
and iron. Since copper was found as an ore at that time, its use was limited to only
domestic use items and hunting weapons.
Initially, the joining of metals was done through pressure welding and lap joints.
Afterward, along with the discovery of other metals, new joining processes were also
developed.
[Referance welding history]
Welding terms
Welding: – A permanent joining process by the application of heat/pressure or both.
Parent metal: – Metal parts that are going to be welded.
Filler materials: – Materials used to fill the gap of the joint.

3. weld alloys:- A process where different types of metal with different microstructure or
mechanical properties, are joined together.
Consumables
Consumables have an important role in weld operations, including filler metals, shielded
gases, fluxes, etc., which help to complete the weld successfully.
Selection of consumables
usually, consumables are chosen in similar composition/properties of the parent
material to produce welds having a similar material composition and mechanical
properties, but when joining dissimilar metals, consumables are chosen that incorporate
the properties of the material composition of both metals.
Energy sources
In this method, heat energy is used to join the two parts together which is obtained from
different sources. Welding processes are classified on the basis of these sources.
Following are the main sources used for obtaining thermal energy: –
● By electricity
● Using flammable gases
● By chemical reaction
● By laser rays
Basics features of welding
Initially, welding technology began as an art, its use was limited to making household
items, hunting weapons, etc. But in the modern era, It also involves a high skill level and
practical knowledge of metallurgy.
Take a look at some of the fundamentals of welding:
● It provides a permanent and clean joint. which is as strong as the base metal.

4. ● It is also capable of bonding metals with different chemical structures.
● Usually, welding is the most economical way to join parts in terms of material
use and manufacturing cost
● Welding work can be accomplished both “in the field and in the workshop”,
and through this new equipment can be produced and damaged equipment
can be repaired at a lower cost.
Types of welding Processes
Several welding and brazing types are being applied by industries along with soldering
methods. These processes can be defined on the basis of the use of energy sources.
Arc Welding Process
The arc process is defined as a fusion welding process wherein the heat is produced by
an electric arc, generated between the electrode and base metal.
All those joining processes that are done using electric energy are kept in the category
of arc welding such as: –
Further details >>> Arc welding process
Gas welding Process
In order to obtain the desired heat for the fusion of filler materials and base metals, gas
welding processes use a mixture of oxygen/air with fuel gases such as acetylene,
hydrogen, propane, butane, etc.
Further details: – Gas welding process
Resistance Welding Process
It is a group of welding processes that use electric energy, wherein the coalescence is
produced by the heat obtained from the resistance of the work to the flow of electric
current in a circuit of which the work is a part and by the application of pressure.
Further details: – Resistance welding process

5. Solid-State Welding Process
The solid-state process is a set of welding processes wherein, it is performed with the
application of pressure and at temperatures below the melting point of the parent metal.
filler metal is not required in these processes.
Further details: Solid-State Welding Process
Thermo-Chemical Process
In the thermochemical process, the desired heat is obtained by implementing the
exothermic reactions,
Further details: Thermo-Chemical Process
Radiant Energy Process
In Radiant Energy Process, the desired heat is obtained by focusing the energy beam
on the base metal.
Further details: Radiant Energy Process
Common applications
Welding has been employed in the industry as a tool for:
Regular fabrication of automobile cars, air-crafts, refrigerators, etc.
Repair and maintenance work, such as joining broken parts, rebuilding worn-out
components, etc.
The common applications are listed below:
● Aircraft Construction

6. Welded engine mounts, turbine frame for a jet engine, rocket motor fuel, and oxidizer
tanks, ducts, fittings, cowling, components, etc.
● Automobile Construction
Arc welded car wheels, steel rear axle housing, frame side rails. automobile frame
brackets, etc.
● Bridges
Pier construction, Shop and field assembly of lengths, etc.Section lengths.
● Buildings
Column base plates, trusses, Erections of structure, etc.
● Pressure vessels and Tanks
Clad and Lined steel plates, shell construction joining of the nozzle to the shell, etc.
● Storage Tanks
Oil gas and water storage tank
● Rail Road Equipment
Locomotive, Underframe, air receiver, engine.Front and rear hoods, etc.Front and rear
hoods, etc.
● Pipings and pipelines
Rolled plate piping, open pipe joints, oil, gas, and gasoline pipelines, etc.
● Ships

7. Shell frame, deck beams, and bulkhead stiffeners. girders to shells.Bulkhead webs to
plating, etc.
Other useful applications
Trucks and trailers.Machine tool frames, cutting tools, and dies.Household and office
furniture.Earthmoving machinery and cranes.
Best welding practices
Usually, welding produces ultra-violet rays and toxic fumes that are extremely harmful to
human health. This can be avoided by following some necessary safety measures.
A welder can protect himself by following some best welding practices, such as:
● Always check the surroundings for any flammable materials such as dry wood,
paper, gasoline, oil, grease, paint or chemicals, etc. Keep these elements,
away from the area, if not possible, cover it with a fire blanket
● Always check the machine and tools before starting work. If there is any
defect, do not use it as it can cause some danger
● The machine should be grounded. If the current leaks from somewhere, then it
should be grounded directly, this avoids the risk of getting a herb.
● Always use a proper helmet including (black shaded glass) to protect your
eyes from ultraviolet rays.
● Use a proper mask to avoid inhaling toxic gases.
● Use appropriate hand gloves, sleeves, and aprons for protecting body parts
from heating/burning or shocking risks.
Further details >>> Safety recommendations in the welding operation