the slide shows the advance welding technic like as Tig And Mig Welding Process. it help people to understand the advance manufacturing process for welding. it made by Sk Samsuddin.

1. Made by Sk Samsuddin

2. INTRODUCTION:
Welding is a process for joining two similar or dissimilar metals by
fusion. It joins different metals/alloys, with or without the application of
pressure and with or without the use of filler metal.
The fusion of metal takes place by means of heat. The heat may be
generated either from combustion of gases, electric arc, electric resistance,
chemical reaction, frictional heat, or by sound and light energy.

3.  Now a day, there is huge demand for welding new materials and
larger thickness component.
 But gas flame welding which was first known to the welding
engineer is no longer satisfactory and hence scientist invented
advance method such as TIG, MIG,PAW,EBW,LBW etc

5. CLASSIFICATIONOF WELDINGANDALLIEDPROCESSES
(A) Welding Processes
1. Gas Welding Processes
1 Oxy-acetylene welding
2 Air-acetylene welding
3 Oxy-hydrogen welding
2. Arc Welding Processes
1. Carbon Arc Welding
2. Shielded Metal Arc Welding
3. Submerged Arc Welding
4. Gas Tungsten Arc Welding (TIG)

6. 5. Gas Metal Arc Welding (MIG)
6. Plasma Arc Welding
7. Atomic Hydrogen Welding
8. Electro-slag Welding
9. Stud Arc Welding
10. Electro-gas Welding
3. Resistance Welding
1. Spot Welding
2. Seam Welding
3. Projection Welding
4. Resistance Butt Welding
5. Percussion Welding

7. 4. Solid-State Welding Processes
1. Friction Welding
2. Explosive Welding
3. Diffusion Welding
4.Ultrasonic
5. Thermit Welding Processes
1. Thermit Welding
2. Pressure Thermit Welding
6. Radiant Energy Welding Processes
1. Laser beam Welding
2. Electron Beam Welding

8. ARC WELDINGPROCESSES
The process, in which an electric arc between an electrode and a
workpiece or between two electrodes is utilized to weld base metals, is
called an arc welding process.
Arc welding is the most extensively employed method of joining metal
parts. Here source of heat is an electric arc.

11. TUNGSTENINERT GAS WELDING
 Tungsten Inert Gas (TIG) or Gas Tungsten Arc (GTA) welding
is the arc welding process in which arc is generated between
non consumable tungsten electrode and work piece.
 The tungsten electrode and the weld pool are shielded by an
inert gas normally argon and helium.
 Figures show the principle of tungsten inert gas welding
process.

14. Argon is most widely than helium because it is a heavier gas,
producing better shielding at lower flow rate. The shielding gas
displaces the air surrounding the arc and weld pool. This
prevents the contamination of weld metal by oxygen and
nitrogen in the air.
The shielded gas is supplied to the weld zone from the gas
cylinder.
Filler metal may or may not be used. When a filler metal rod is
used, it is usually fed manually into the weld pool.

15. Electrode used in this process are made up of tungsten and
tungsten alloys. The tungsten electrode is used only to generate an
arc .the arc does not melt the tungsten, which has melting point
above 3300 deg.c.
The TIG torch is moved along the groove steadily to effect the
welding and complete the joint.
The TIG process used for welding aluminum and its alloy, stainless
steel, magnesium alloy nickel base alloy, copper base alloy, carbon
steel and low alloy steel.

17. Advantages It produces high quality weld in nonferrous metals.
 Practically no weld cleaning is necessary
 The arc and weld pool are clearly visible to the welder.

18. Disadvantages
 Deposition rates are lower and hence completion time for weld
joint is longer than in other process.
 The welding cost is more because it uses argon gas for shielding.
 Skill requirement is more.

19. Applications
 The aerospace industry is one of the primary users of gas
tungsten arc welding.
 Many industries use GTAW for welding thin work pieces ,
especially nonferrous metals.
 It is used extensively in the manufacture of space vehicles, and is
also frequently employed to weld small-diameter, thin-wall
tubing such as those used in the bicycle industry.

20. GAS METAL ARC WELDING (MIG)
Gas metal arc welding is a gas shielded metal arc welding process
which uses high heat of an electric arc between continuously fed,
consumable electrode wire and the material to be welded.
The of the consumable electrode wire is melted and the molten metal
is transferred across the arc into the weld pool.
The arc and the weld pool are protected from atmospheric
contamination by the shielding gas supplied through the nozzle.
The arc can be shielded by an active (Co2) or inert (Ar, He).
If the inert gas is used then it is termed as Metal inert gas (MIG) and
if shielded gas is active gas then GMAW is called as (MAG) welding.

22. Typical setup for
GMAW or MIG welding process
The consumable electrode is in the form of a wire reel which is fed at a
constant rate, through the feed rollers.
The welding torch is connected to the gas supply cylinder which provides the
necessary inert gas.
The electrode and the work-piece are connected to the welding power supply.
The current from the welding machine is changed by the rate of feeding of
the electrode wire.
Normally DC arc welding machines are used for GMAW with electrode
positive (DCEP). The DCEP increases the metal deposition rate and also
provides for a stable arc and smooth electrode metal transfer.

27. Advantages
No flux required
High welding speed
Increased corrosion resistance
Easily automated welding
Welds all metal including aluminum and stainless steel.

28. Disadvantages
Process is costly
Less portable than manual metal arc welding
Poor quality of weld is produced if air draught exist in working
area.

29. PLASMA ARC WELDING
 Plasma arc welding is an arc welding process in which welding
heat is obtained from a constricted arc set up between a tungsten
electrode and the job.
 The process employs two inert gases, one forms the arc plasma and
the second shields the arc plasma. Filler metal may or may not be
added.

31. Principle of operation:
 A small amount of pure argon gas flow is allowed through the inner
orifice surrounding the tungsten electrode to form the plasma gas.
 Because of the squeezing action of the constricting nozzle, the arc is
concentrated and straight.
 This increases the heat contained per unit volume of the arc plasma
so arc temperature of the order of 11000 degree c. can be obtained.

32.  Plasma arc welding process can be divided into two basic types:
1. Non-transferred arc process: The arc is formed between the
electrode (-ve) and water cooled constricting nozzle (+ ve).Arc plasma
come out of the nozzle as a flame.
2. Transferred arc process: The arc is formed between the electrode (-
ve) and the workpiece (+).In other words the arc is transferred from
electrode to the workpiece.

33. Advantages
 Stability of arc
 Uniform penetration
 Simplified fixture
 Excellent weld quality
 Rewelding of the root of the joint saved

34. Disadvantages
 Welders need ear plug because of unpleasant, disturbing and
damaging noise.
 More chance of electrical hazards
 Inert gas consumption is high
 Skilled welder required.

35. Applications
 Tube mill application
 Welding of stainless steel tubes
 For melting high melting point metal

36. Resistance Welding
Resistance welding processes are pressure welding processes in which
heavy current is passed for short time through the area of interface of
metals to be joined.
These processes differ from other welding processes in the respect that
no fluxes are used, and filler metal rarely used.
Heat is generated in localized area which is enough to heat the metal to
sufficient temperature, so that the parts can be joined with the
application of pressure. Pressure is applied through the electrodes.

37. The heat generated during resistance welding is given by following
expression:
H = I 2 R T
Where, H is heat generated
I is current in amperes
R is resistance of area being welded
T is time for the flow of current.

38. Resistance welding is divided into following process.
1. Spot Welding
2. Seam Welding
3. Projection Welding
4. Resistance Butt Welding
5. Percussion Welding

39. SPOT WELDING
Spot welding is the resistance welding process in which overlapping
sheet are joined by fusion at one or more spots by the heat generated
by resistance to the flow of electric current through workpiece that are
held together under force by two electrode.
It essentially consists of two electrodes, out of which one is fixed. The
other electrode is fixed to a rocker arm for transmitting the mechanical
force from a pneumatic cylinder.

40. When the current is turned on, the pieces are heated at their point of
contact to a welding temperature.
The current is cut-off and mechanical pressure is then applied by the
electrodes to forge the welds, finally the electrode open.
Current usually range from 3000 A to 40000 A , depending on the
material being welded and their thickness.
This may be used to weld steel and other metal parts up to a total
thickness of 12 mm.

43. Advantages
 High production rate
 Dissimilar metal can be welded
 High skill not required
 Most suitable for welding sheet metal

44. Disadvantages
 Suitable for thin sheet only
 High equipment cost

45. Applications of Spot Welding
It has applications in automobile and aircraft industries.
Spot welding of two 12.5 mm thick steel plates has been done
satisfactorily as a replacement for riveting.
Containers and boxes frequently are spot welded.

46. Radiant Energy Welding Processes
These type are also called ‘newer’ since these are not in used for many
years and have been developed very recently. The types are
1. Electron beam welding
2. Laser beam welding

47. Electron beam welding
 Electron beam welding is a process in which the heat is generated when the
electron beam impinges on work piece. As the high velocity electron beam
strikes the surfaces to be welded, their kinetic energy changes to thermal energy
and hence causes the workpiece metal to melt and fuse.
 The beam is created in a high vacuum (10-3 to 10-5 mm of hg )
 This process employs an electron gun in which the cathode in form of hot
filament of tungsten or tantalum is the source of a stream of electrons.
 The electrons emitted from filament accelerated to a high velocity to the anode
because of the large potential difference that exists between them.
 The electron beam is focused by a magnetic lens system on the workpiece to be
welded.

49. The depth of penetration of the weld depends on the electron speed which
in turn is dependent upon the accelerating voltage.
When the high velocity electron beam strikes the work-piece all the
kinetic energy is converted to heat.
As these electrons penetrate the metal, the material that is directly in the
path is melted which when solidifies form the joint.

50. Advantages
The penetration of the beam is high.
The process can be used at higher welding speeds typically between 125
and 200 mm/sec.
No filler metal or flux needs to be used in this process.
The heat liberated is in a narrow zone, thus the heat affected zone is
minimal as well as weld distortions are virtually eliminated.
It can weld or cut any metal or ceramic, diamond, sometimes as thick as
150 mm.

51. Disadvantages
 High operating cost
 Expensive equipment
 Work size is limited by the size of the chamber.

52. Application
Automobile, airplane, aerospace, farm and other type of
equipment are being welded by the electron beam process.

53. Laser Beam Welding
Laser is a abbreviation of light amplification by stimulated emission of
radiation.
The laser beam welding process is the focusing of a monochromatic light
into extremely concentrated beams.
It employs a carefully focused beam of light that concentrates tremendous
amount of energy on a small area to produce fusion.
The laser beam welding consist of electrical storage unit, capacitor tank ,
triggering device , flash tube wrapped with a wire , focusing lens mechanism
and work table.

54.  When capacitor bank is triggered, energy is injected into the wire that
surrounds the flash tube.
 The flash tube or lamp are designed for the operation at a rate of thousand of
flashes per second.
 The lamp become a efficient device for converting electrical energy into light
energy, the process of pumping the laser. The laser is then activated.
 The beam is emitted through the coated end of the lasing material.
 The beam goes through a focusing device where it is pin-pointed on the
workpiece. Fusion takes place and the weld is accomplished.

56. Advantages
 This process can be used to weld dissimilar metals with widely
varying physical properties.
 Laser welding holds thermal distortion and shrinkage to a
minimum.
 High production rate.
 Weld can be made with a high degree of precision.

57. Disadvantages
 High energy losses.
 Highly skilled operation.
 High equipment cost.
 Eye protection required.

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