Selection Of Welding Processes and Application Of welding Process

Selection of welding process

A wide range of welding processes are available to choose.
These were developed over a long period of time. Each process
differs in respect of their ability to apply heat for fusion,
protection of the weld pool and soundmen of welds joint the
so performance of the weld joint. However, selection of a
particular process for producing a weld joint is dictated by
the size and shape of the component to be manufactured, the
metal system to be welded, availability of consumables and
machines, precision required and economy. Whatever process is
selected for developing weld joint it must be able to perform
the intended function for designed life. Welding processes
with their field of applications are given below:

  1.  Resistance welding: Automobile
  2. Thermite welding: Rail joints in
  3. Tungsten inert gas welding: Aerospace and nuclear
  4. Submerged arc welding: Heavy engineering, ship
  5. Gas metal arc welding: Joining of metals
    (stainless steel, aluminium and magnesium) sensitive
    to atmospheric gases

Applications of welding

General applications

The welding is widely used for fabrication of pressure
vessels, bridges, building structures, aircraft and space
crafts, railway coaches and general applications besides
shipbuilding, automobile, electrical, electronic and defense
industries, laying of pipe lines and railway tracks and
nuclear installations.

Specific components need welding for fabrication

1. Transport tankers for transporting oil, water, milk
2. Welding of tubes and pipes, chains, LPG cylinders and
other items.
3. Fabrication of Steel furniture, gates, doors and door
frames, and body
4. Manufacturing white goods such as refrigerators, washing
5.microwave ovens and many other items of general

The requirement of the welding for specific area of the
industry is given in following section.

Oil AndGas
1. Welding is used for joining of pipes, during laying of
crude oil and gas pipelines, construction of tankers for
their storage and transportation. Offshore structures,
dockyards, loading and unloading cranes are also produced by

Nuclear Industry
2. Spheres for nuclear reactor, pipe line bends, joining of
pipes carrying heavy water require welding for safe and
reliable operations.

Defense industry
3. Tank body fabrication, joining of turret mounting to main
body of tanks are typical examples of applications of welding
in defense industry.

Electronic industry
4. Electronic industry uses welding to limited extent e.g.
joining leads of special transistors but other joining
processes such as brazing and soldering are widely used.
5. Soldering is used for joining electronic components to
printed circuit boards (PCBs).
6. Robotic soldering is very common for joining of parts to
printed circuit boards of computers, television,
communication equipment and other control equipment etc.

Electrical Industry
7. Components of both hydro and steam power generation
system, such as penstocks, water control gates,
condensers, electrical transmission towers and distribution
system equ
ipment are fabricated by welding. Turbine
blades and cooling fins are also joined by welding.

Surface transport
8. Railway: Railway uses welding extensively for fabrication
of coaches and wagons, repair of wheel, laying of new railway
tracks by mobile flash butt welding machines and repair of
cracked/damaged tracks by thermite welding.
9. Automobiles: Production of automobile components like
chassis, body and its structure, fuel tanks and joining of
door hinges require welding.

Aerospace Industry
10. Aircraft and Spacecraft: Similar to ships, aircrafts were
produced by riveting in early days but with the introduction
of jet engines welding is widely used for aircraft structure
and for joining of skin sheet to body.
11. Space vehicles which have to encounter frictional heat as
well as low emperatures require outer skin and other parts of
special materials. These materials are welded with full
success for achieving safety and reliability