all about welding

1. Azmat Ali Khan 12mt34
Usman Nazir 12mt35
Naveed Imran 12mt28
Haseeb Ahmad 12mt32
Muhammad Farhan 12mt13
Qamar Zia 12mt10
Mazhar Hussain 12mt33

3. What is WELDING
 in engineering, any process in which
two or more pieces of metal are
joined together by the application of
heat, pressure, or a combination of
both.

4. Master chart of Arc Welding and Related Methods

5. Common Welding Types
 Arc Welding (AW)
 Oxyfuel Gas Welding(OFW)
Resistance Welding

6. Types of ArC Welding
 ConsumAble eleCTrodes ArC
Welding
 non ConsumAble eleCTrodes ArC
Welding

7. Types of ConsumAble
eleCTrode AW proCesses
 shielded meTAl ArC Welding
(smAW)
 submerged ArC Welding (sAW)
 flux Cored ArC Welding (fCAW)
 meTAl ArC Welding (gmAW or
mig)

8. Types of non ConsumAble
eleCTrodes AW proCesses
gAs TungsTen ArC Welding
(gTAW)
plAsmA ArC Welding (pAW)
CArbon ArC Welding (CAW)

9. Shielded Metal Arc Welding

10. sheilded meTAl ArC
Welding
 It is performed by striking an arc
between a coated-metal electrode
and the base metal.
 Flux- the coating of the metal
electrode will form as shield to the
molten metal.

11. SMAW OPERATION

12. Arc Welding MAchines

13. Electrode and Holder

14. AdvAnTAges of smAW
 High quality welds are made rapidly
at a low cost.
 Can be used easily even to thick and
wide work piece to be joined.
 Can be used from thinner to thicker
materials.

15. disAdvAnTAges smAW
 Consumes bigger electric current
 Dirty work finish
 Root pass is lower than TIG and MIG
 Prone to slag inclusions
 Weld deposits is prone to blue holes

16. sAW (submerged ArC Welding)

17. submerged ArC Welding
(sAW)
 Is a process in which welding is
done by an automatic electrode
feeding machine wherein the tip of
the electrode is submerged into a
granular flux which shields the arc
and the molten metal.

18. submerged ArC Welding

19. sAW Welding mAChine

20. SAW block diAgrAm

21. SAW APPlicATioNS
 widely used in heavy steel plate
fabrication work.
 welding of structural shapes.
 longitudinal seam of larger diameter pipe.
 manufacture of machine components for
all types of heavy industry.
 manufacture of vessels.
 pressure and storage tanks.

22. AdvANTAgeS of SAW
 high quality of the weld metal.
 extremely high deposition rate and speed.
 smooth, uniform finished weld with no spatter.
 little or no smoke.
 no arc flash, thus minimal need for protective
clothing.
 high utilization of electrode wire.
 easy automation for high-operator factor.
 normally, no involvement of manipulative skills.

23. diSAdvANTAgeS of SAW
 used only to weld mild and low-alloy high-strength
steels.
 Unseen arc and puddle can cause poor
penetration.
 high-heat input, slow-cooling cycle can be
a problem when welding quenched and
tempered steels.
 limited-position welding process only flat
and horizontal

24. flUXed cored Arc
WeldiNg

25. flUX cored Arc WeldiNg
(fcAW)
 is an automatic or semi-automatic
electric arc welding process that
uses an arc between a continuously
fed flux-filled electrode and the weld
pool. The process is used with
shielded gas from a flux contained
within the tubular electrode with or
without additional shielding from an
externally supplied gas.

26. fcAW flUX filled
elecTrode ANd Torch

27. No ShieldiNg gAS (fcAW)

28. With Shielding Gas (FCAW)

29. Two Types of FCAW
 no shielding gas
- using flux core in the tubular consumable
electrode
 uses a shielding gas
- gas that must be supplied by an external
supply. This is known informally as "dual shield"
welding.

30. Uses of FCAW
Mild and low alloy steels
Stainless steels
Some high nickel alloys
Some wear facing/surfacing
alloys

31. Advantages of FCAW
 FCAW may be an "all-position" process with the
right filler metals (the consumable electrode)
 No shielding gas needed making it suitable for
outdoor welding and/or windy conditions
 A high-deposition rate process (speed at which
the filler metal is applied) in the 1G/1F/2F
 Some "high-speed" (e.g., automotive
applications)
 Less pre cleaning of metal required
 Metallurgical benefits from the flux such as the
weld metal being protected initially from external
factors until the flux is chipped away

32. diSAdvANTAgeS of fcAW
 Melted Contact Tip – happens when the electrode actually
contacts the base metal, thereby fusing the two metals.
 Irregular wire feed – typically a mechanical problem
 Porosity – the gases (specifically those from the flux-core)
don’t escape the welded area before the metal hardens,
leaving holes in the welded metal
 More costly filler material/wire as compared to GMAW
 Less suitable for applications that require painting, such as
automotive body works.
 Cannot be used in a rugged environment limited to shop
use only.

33. FCAW Equipment set up

34. meTAl iNerT gAS
WeldiNg

35. GMAW or MIG
 is an electric arc welding process which joins
metals by heating them with an arc established
between a continuous filler metal (consumable)
electrode and the work.
 Shielding of the arc and molten weld pool is
obtained entirely from an externally supplied
gas or gas mixture both inert and reactive
gases.

36. GMAW Welding Operations

37. MIG Machine with Spool
feeder

38. GUN used in GMAW

39. MIG Torch

40. GMAW Weld Diagram

41. Advantages of GMAW
 Produced High quality welds & much faster than with
SMAW and TIG welding.
 No flux is used no slag entrapment in the weld metal.
 Very little loss of alloying elements as the metal
transfers across the arc.
 Minor weld spatter is produced, and it is easily
removed.

42. Advantages of GMAW
 Versatile and can be used with a wide variety of
metals and alloys, such as Aluminum, Copper,
Magnesium,
Nickel, Iron and many of their alloys.
 The process can be operated in several ways, including
semi- and fully automatic.
 MIG welding is widely used by many industries for
welding a broad variety of materials, parts, and
structures.

43. Disadvantages of GMAW
 IT cannot be used in the vertical or overhead welding
positions due to the high heat input and the fluidity of
the weld puddle.
 Has complex equipment compared to equipment used
for the shielded metal-arc welding process.

44. NON
CONSUMABLE
ELECTRODES

45. Gas Tungsten Arc Welding
 Gas tungsten arc welding (GTAW) is an AW
process that
 uses a nonconsumable tungsten electrode and
an inert gas for arc shielding. The term TIG
 welding (tungsten inert gas welding) is often
applied to this process (in Europe, WIG
 welding is the term—the chemical symbol for
tungsten is W, for Wolfram).

47. Temperature and shelding
gases
 Tungsten is a good electrode
material due to its high melting
point of 3410C (6170F).
 Typical shielding gases include
argon, helium, or a mixture of these
gas elements.

48. APPLICATION
 GTAWisapplicable tonearly allmetals
in a wide range of stock thicknesses.
 It can also be used for joining
various combinations of dissimilar
metals.
 Its most common applications are
for aluminum and stainless steel.

49. LIMITATIONS
 Cast irons, wrought irons, and of
course tungsten aredifficult to weld
by GTAW.
 In steel welding applications, GTAW
is generally slower and more costly
than the consumable electrode AW
processes, except when thin
sections are involved and very-high-quality
welds are require.

50. ADVANTAGES
 Advantages of GTAW in the
applications to which it is suited
include high-quality welds, no weld
spatter because no filler metal is
transferred across the arc, and little
or no post weld cleaning because no
flux is used.

51. PLASMA ARC
WELDING

52. Plasma Arc Welding
 Plasma arc welding (PAW) is a special
form of gas (TAW) in which a constricted
plasma arc is directed at the weld area.
 In PAW, a tungsten electrode is
contained in a specially designed nozzle
that focuses a high-velocity stream of
inert gas (e.g., argon or argon–hydrogen
mixtures) into the region of the arc to
form a highvelocity,intensely hot plasma
arc stream

54. TEMPERATURES
 Temperatures in plasma arc welding
reach 17,000C (30,000F) or greater,
hot enough to melt any known
metal.
 The reason why temperatures are so
high in PAW (significantly) higher
than those in GTAW) derives from
the constriction of the arc.

55. ADVANTAGES
 its advantages in these applications
include good arc stability,better
penetration control than most other
AW processes, high travel speeds,
and excellent weld quality.
 The process can be used to weld
almost any metal, including
tungsten.

56. LIMITATIONS
 Difficult-to-weld metals with
PAWinclude bronze, cast irons, lead,
and magnesium.
 Other limitations include high
equipment cost and larger torch size
than other AW operations,which
tends to restrict access in some joint
configurations.

57. Carbon arc welding
 Carbon arc welding (CAW) is an arc-welding
process in which a non
consumable carbon (graphite)
electrode is used.
 It has historical importance because
it was the first arc-welding process
to be developed, but its commercial
importance today is practically nil.

58. APPLICATIONS
 The carbon arc process is used as a
heat source for brazing and for
repairing iron castings.
 It can also be used in some
applications for depositing wear-resistant
materials on surfaces.
 Graphite electrodes for welding have
been largely superseded by
tungsten(in GTAW and PAW).

59. GAS WELDING
AND ITS TYPES

60. Oxygen Fuel Gas Welding
(OFW)
is a group of welding processes
which join metals by heating with
a fuel gas flame or flares with or
without the application of pressure
and with or without the use of filler
metal.

61. Types of Oxy-fuel Gas Welding
 Oxy-Acetylene or Oxygen- Acetylene Gas
Welding
 Oxy-Hydrogen or Oxygen- Hydrogen Gas
Welding
 Methylacetone-Propadiene Gas Welding
 Pressure Gas Welding.

62. Advantages of Oxy-fuel
Gas Welding
 Easy to use both welding and cutting
 Controlled heat input
 Controlled bead size
 Convenient to use in welding thin sheets, tubes
and small diameter pipes

63. Disadvantages of Oxy-Fuel
Gas Weldinmoo
 Cannot be use to weld on thick work
piece.
 Expensive gas

64. Oxy-Acetylene Diagram
Welding Equipment

65. Complete Oxy-Acetylene
Welding Equipment

66. Resistance Welding
 is a process in which the fusing temperature is
generated at the joint by the resistance to the flow of an
electrical current.
 is accomplished by clamping two or more sheets of
metal between copper electrodes and then passing an
electrical current through them. When the metals are
heated to a melting temperature, forging pressure is
applied through either a manual or automatic means to
weld the pieces together.
 Two common types are Spot and Seam welding

67. 2 Types of Resistance
Welding
SPOT WELDING
SEAM WELDING

68. SPOT WELDING
The metal to be joined is
placed between two
electrodes and pressure
is applied.
A charge of electricity is
sent from one electrode
through the material to
the other electrode.

71. SEAM Welding
is
like spot welding
except that the
spots overlap each
other, making a
continuous weld
seam.