The document outlines the welding process as a method of joining materials through heating and pressure, with various techniques such as arc welding, gas welding, and resistance welding detailed. Welding is widely used in industries like automotive, aerospace, and construction due to its efficiency and ability to create permanent joints. It also covers the equipment needed for welding, the history of the process, and its advantages and limitations.

1. WELDING PROCESS
UNIVERSTY OF SALAHADDIN – COLLEGE OF ENGENEERING – MECHANICAL DEPARTMENT
– Welding is a materials joining process which
produces coalescence of materials by heating
them to suitable temperatures with or without the
application of pressure or by the application of
pressure alone, and with or without the use of filler
material.
– Welding is used for making permanent joints.
– It is used in the manufacture of automobile bodies, aircraft
frames, railway wagons, machine frames, structural works,
tanks, furniture, boilers, general repair work and ship
building.
(i). Arc welding
• Carbon arc
• Metal arc
• Metal inert gas
• Tungsten inert gas
• Plasma arc
• Submerged arc
• Electro-slag
(ii). Gas Welding
• Oxy-acetylene
• Air-acetylene
• Oxy-hydrogen
(iii). Resistance Welding
• Butt
• Spot
• Seam
• Projection
• Percussion
(iv)Thermit Welding
(v)Solid State Welding
Friction
Ultrasonic
Diffusion
Explosive
(vi)Newer Welding
Electron-beam
Laser
(vii)Related Process
Oxy-acetylene cutting
Arc cutting
Hard facing
Brazing
Soldering
While often an industrial process, welding can be
done in many different environments, including
open air, underwater and in outer space.
Until the end of the 19th century, the only
welding process was forge welding, which
blacksmiths had used for centuries to join iron
and steel by heating and hammering them.
Arc welding and oxyfuel welding were among
the first processes to develop late in the
century, and resistance welding followed
soon after.
• Equipments:
• A welding generator (D.C.) or Transformer (A.C.)
• Two cables- one for work and one for electrode
• Electrode holder
• Electrode
• Protective shield
• Gloves
• Wire brush
• Chipping hammer
• Goggles
A fusion welding process in which coalescence of
the metals is achieved by the heat from an
electric arc between an electrode and the work
 Electric energy from the arc produces
temperatures ~ 10,000 F (5500 C), hot enough
to melt any metal
 Most AW processes add filler metal to increase
volume and strength of weld joint
An electric arc is a discharge of electric current
across a gap in a circuit
 It is sustained by an ionized column of gas
(plasma) through which the current flows
 To initiate the arc in AW, electrode is brought
into contact with work and then quickly
separated from it by a short distance
A pool of molten metal is formed near electrode
tip, and as electrode is moved along joint,
molten weld pool solidifies in its wake
WeldabilityWeldability of a Metalof a Metal
Classification of welding processes:What is it?History of Welding
Where can welding be done?
• Metallurgical Capacity
– Parent metal will join with the weld metal without
formation of deleterious constituents or alloys
• Mechanical Soundness
– Joint will be free from discontinuities, gas porosity,
shrinkage, slag, or cracks
• Serviceability
– Weld is able to perform under varying conditions or
service (e.g., extreme temperatures, corrosive
environments, fatigue, high pressures, etc.)
SUPERVISOR : MRS.GAWHAR
PREPARED BY:
-DARAWAN WAHID
FIRST STAGE (A) 2013-2014
Advantages
– Most efficient way to join
metals
– Lowest-cost joining method
– Affords lighter weight
through better utilization of
materials
– Joins all commercial metals
– Provides design flexibility
Limitations
• Manually applied, therefore
high labor cost.
• Need high energy causing
danger
• Not convenient for
disassembly.
• Defects are hard to detect at
joints.
DESIGNED BY DARAWAN WAHID
REFERENCE : HTTPS://WWW.GOOGLE.IQ/?GFE_RD=CR&EI=4QPRU7I3NOVC8GFF-YHIBA#Q=CASTING+PROCESSES