The document outlines various welding equipment, focusing on power sources, electrode holders, welding cables, and electrodes. It provides detailed descriptions of different types of power sources such as AC, DC, and inverter systems, and discusses their advantages and disadvantages. Additionally, it covers the specifications and importance of electrodes, including their types, coatings, and selection criteria based on welding needs.

1. ER. PEEYUSH CHAUHAN
ASSISTANT PROFESSOR
DEPARTMENT OF MECHANICAL ENGINEERING

2. “Welding equipment's is the tools used in the welding”
The following equipment's used in the welding-
1. Power Source (AC or DC)
2. Electrode Holder
3. Welding Cables
4. Ground Clamp
5. Welding Electrodes
6. Welding Helmets & Hand Shield
7. Protective Cloths
8. Finishing tools – Wire brush, Chipping Hammers.

4. Welding power source is designed to change high voltage low
ampere current into a safe low voltage (Between 50-100
volts) heavy current (above 500 amperes). Power Sources for
Arc Welding transform the power from the grid to controlled
values of voltage and of current suitable to the intended uses.
The power source are generally three types-
1. Direct current power sources
2. Alternate Current power source
3. Combination power source

5. Selection of Power Sources-
1. Availability of power (AC or DC)
2. Available floor space.
3. Location of operation ( Plant or Field)
4. Personal available for maintenance
5. Versatility of equipment's
6. Required output
7. Initial cost & running cost
8. Duty cycle
9. Efficiency
10.Types of work ( Heavy or Light)

6. 1. Direct Current Power Sources-
1. DC Generator Set-
A DC welding generator produce direct current in either
straight or reverse polarity. A DC generator is powered either
by electric motor or a diesel engine.
 The current supplied by the DC generator is created by an
armature rotating in electric field. The armature is rotating
by the electric motor or an engine.
 The generator are designed to rotate at speeds of 1500,
1800 or 3600 rpm to give optimum current value.
 Generator supplied the voltages usually in the range from
15 to 45 volts across the arc.

9. Following advantages of DC generator set are-
1. Straight as well as reverse polarity can be employed.
2. Welding can be carried out in all positions.
3. Nearly all ferrous & non-ferrous metal can be welded.
4. Generator output is not affected by normal variation in
power line voltage.
Following disadvantages of DC generator set are-
1. Highly initial cost
2. Higher maintenance cost
3. Noisy machine operations.

10. 2. AC-DC Rectifiers-
A AC-DC rectifiers can supply any types of current. This type
of machine essentially transformers containing a electrical
device known as rectifier which change AC to DC.
 The rectifier may consists of metal plates coated with
selenium compound or silicon didoes, each unit having a
special property of allowing the current flow in one
direction only.
 A rectifier unit is installed with a fan to cool the
transformer. Its designed for a single phase or three phase
power supply.

12. Following advantages of AC-DC rectifier are-
1. They can provide both straight & reverse polarity.
2. They possess all the advantages of an AC transformer.
3. They have good performance at low welding currents.
4. The current in AC-DC rectifier easily controlled by remote.
Following disadvantages of AC-DC rectifier are-
1. The life of selenium plate is limited to about 7 years under
normal usage.

13. 3. Thyristor-Controlled rectifier-
A thyristor controlled rectifier use instead of conventional
rectifier in welding machine. A thyristor is a solid state device
which allows current to flow in one direction, i.e., its behave
as a normal rectifier. It’s also known as silicon control
rectifier. Basically, thyristor is a three-terminal, four-layer
semiconductor device consisting of alternate layers of p-type
and n-type material.
Thyristor controlled rectifier generally use for SMAW & TIG
welding.

15. 4. Inverter System-
Since the advent of high-power semiconductors such as the
insulated gate bipolar transistor (IGBT), it is now possible to
build a switched-mode power supply capable of coping with
the high loads of arc welding. These designs are known as
inverter welding units.
It generally first rectify the utility AC power to DC; then
switch (invert) the DC power into a stepdown transformer to
produce the desired welding voltage or current. The switching
frequency is typically 10 kHz or higher.

18. 2. Alternative Current Power Sources-
1. AC Generator Set-
An AC generator consists of an alternator that provides
welding current. Its driven by an AC motor or diesel engine.
A typical alternator design normally places the magnetic field
coils on the rotor & the armature coils in the stator.
 An AC generator may deliver current at normal frequency
(60 Hz) or high. The frequency of the output welding
current is controlled by the speed of rotation of the rotor
assembly & by the number of poles in the alternator.

21. 2. AC Transformer-
A welding transformer changes high voltage, low amperage
power to low voltage, high amperage welding power.
An AC transformer is the least expensive, lightest & smallest
welding machine. It takes power directly from the main &
transforms it to the voltage/current required for welding.
 Since AC passes through zero twice every cycle, it means
that there are two period in every cycle when the welding
current is zero during which the arc would extinguish &
make continuous welding difficult. This difficulty is
removed by-
1. Building in automatic Arc Stabilization in welder windings.

23. 2. Electrode coating which produce complete ionization in the
arc stream & keep the arc igniting as the current passes
through zero.
Advantage of AC Transformer-
1. Its least expensive, lightest & smallest welding machine.
2. No Arc blow generate during welding.
3. Workpiece do not get magnetize as do in DC.
4. Low operating & maintenance cost.
5. Noiseless operation because no moving part in transformer.
6. Overall electrical efficiency is high.

24. Disadvantage of AC Transformer-
1. Polarity can’t be change.
2. In AC starting the arc is more difficult than with DC.
3. Poor power factor is inherent in use of transformer of the
constant current type.
Applications-
1. In flux shielded metal arc welding.
2. In industries (200 ampere- 500 ampere)
3. Heavy gauge steel.

26. “Welding cables are use for supply the current in the
electrode & workpiece through power source.”
In the welding two cables are use-
1. Electrode Lead – It join the electrode holder or electrode
to the welding power source.
2. Ground Lead- It join the workpiece to the welding power
source.
 A welding cables or leads are well insulated with rubber &
a woven, fabric reinforcing layer. Above the insulation is
an outer jacket of a durable layer of rubber or neoprene.

27.  Welding cables are produced in several sizes. The smaller
the number, the larger the dimeter of lead.
 The size of the welding leads is selected depending upon
the capacity of welding machine stated in ampere &
maximum length of cable. For Example- 200 Amps
welding machine with 60% duty cycle use 2 number cable
for distance up to 50 meters.
 Welding cable is made from stranded bundles of copper
wire tightly packed and insulated. Welding cable usually
comes with rubber insulation, typically either Neoprene
or Ethylene Propylene Diene Monomer (EPDM)
rubber, and is designed to be fire (small sparks), water,
oil, and abrasion resistant.

28.  Electrical cable is typically categorized by an AWG
(American Wire Gauge) size, where the smaller diameter
cable has a larger number. Cable sizes between #4 and
#4/0 are typically used for welding cable.
 AWG sizes have three numbers, for example, "2 AWG
625/30" This means that the welding cable has a total
cross sectional area of 2 AWG and is made from 625
strands of 30 AWG wire.

30. Connection for leads-
The ground lead connected to the workpiece by-
1. By Bolt.
2. By C-clamp
3. By Tack.
4. By ground Clamp
 The electrode leads is to connected to the welding machine
by Lugs. These lugs are made of a cast copper alloy &
may be covered with fiber insulation layer.
 Lugs are attached to the welding machine cables by
soldering or mechanical methods such as crimping.

33.  Cable connectors are fitting especially designed for joining
two or more length of welding cable to obtain a long cable.
It can be easily connect or disconnect.

35. “An electrode holder, commonly called a stinger, is a
clamping device for holding the electrode securely in any
position.”
Or
“Electrode holder is a device used for mechanically holding
the electrode & conducting current to it.”
The electrode holder have following parts-
1. Jaw
2. Jaw Spreading Lever
3. Insulator
4. Spring
5. Heat Shield
6. Handle

38.  The electrode jaw are made to hold the bare end of the
electrode in either in vertical or angular position. For this
purpose grooves are cut into the jaw.
 The electrode lead is firmly fastened to the electrodes
holder with a lug or mechanical connections with insulator
to protect the operator against electrical shocks.
 The electrode holder are generally matched to the size of
lead & amperage. The electrode holder are generally
available in size that range from 150 Amp. to 500 Amp.
There are following requirements of a good electrode holder-
1. It should be light to minimize fatigue incurred by the
welder.
2. It should not be heat up too rapidly.

39.  The electrode jaw are made to hold the bare end of the
electrode in either in vertical or angular position. For this
purpose grooves are cut into the jaw.
 The electrode lead is firmly fastened to the electrodes
holder with a lug or mechanical connections with insulator
to protect the operator against electrical shocks.
 The electrode holder are generally matched to the size of
lead & amperage. The electrode holder are generally
available in size that range from 150 Amp. to 500 Amp.
There are following requirements of a good electrode holder-
1. It should be light to minimize fatigue incurred by the
welder.
2. It should not be heat up too rapidly.

40. 3. It should produce a balanced feeling when held in the
operator’s hand, with the cable draped over the operator’s arm
& with the average length of metallic electrode in the holder.
4. It should receive & eject the electrode rapidly.
5. All exposed surface of the electrode holder including jaws
should be protected by insulator.
6. For the ease of welder the handle of the electrode holder
may be water cooled when welding heavy worked.

42. “An electrode is a piece of wire or a rod ( of a metal or alloy)
with or without flux covering, which carries current for
welding. At one end it’s gripped in a holder & an arc is set up
at other.”
Or
An electrode is an electrical conductor used to make contact
with a nonmetallic part of a circuit (e.g. a semiconductor, an
electrolyte, a vacuum or air).
The word was coined by William Whewell at the request of
the scientist Michael Faraday from two Greek words:
elektron, meaning amber (from which the word electricity is
derived), and hodos, a way.
The electrophore, invented by Johan Wilcke, was an early
version of an electrode used to study static electricity.

43. Welding Electrode
Non Consumable Consumable
(Refractory) (Metallic)
Carbon Tungsten Bare Flux Covered
Or Graphite Electrodes Electrodes Electrodes
Electrodes
Pure Thoriated Zirconiated DC AC
Tungsten Tungsten Tungsten Electrode Electrode
DCSP DCRP

44. Flux Covered Electrode
Sizes Positions Coating
All Position Low
Length Diameter Flat Medium
250 mm 1.5 Horizontal Heavy
300 mm 2.0 Vertical Cellulose
350 mm 2.5 Overhead Iron Powder
450 mm 3.15/3.25
4,5,6.3 mm etc. Ferrous Nonferrous
Cast Alloy High Carbon Al Al Lead Phosphor
Iron Steel Steel Bronze Bronze Bronze

45. 1. Non-consumable Electrode-
 It’s made of high melting points materials like carbon
(67000F), pure tungsten (61500F) or alloy tungsten.
 These electrodes don’t melt during welding. These
electrode length goes on decreasing with the passage of
time because of vaporization & oxidation of the electrode
materials during welding.
 Non consumable electrodes are copper coated carbon &
graphite electrode because of copper coating increase the
electrical conductivity or current conducting capacity of
the electrodes.
 Carbon or graphite electrodes ranging from 2 mm to 15
mm are employed for welding purposes.

46.  Alloying pure tungsten increase emissivity, resistance to
contamination, arc stability & electrode life.
 Tungsten/alloy tungsten electrodes ranging from 0.5 mm
to 6 mm diameter are commonly used during welding.
 Tungsten & alloy tungsten electrodes are generally used
with DCSP.
Electrode Color Classification
Pure Tungsten Green
1% Thorium Yellow
2% Thorium Red
0.3 -0.5% Zirconium Brown

47. 2. Consumable Electrode-
 It’s made of low melting point electrodes made up of
different metals & their alloys.
 The electrode itself adds filler metals.
Types of Consumable Electrodes-
Consumable Electrodes are following types-
1. Bare Electrodes- It’s consist of metal or alloy wire without
any flux coating. Bare electrodes are used for welding
manganese steel and other purposes where a coated electrode
is not required or is undesirable.
2. Light Coated Electrodes- It’s consists a coating factor
approximately 1.25. Example- Citobest electrode of advani
oerlikon (A.O).

48. 3. Medium Coated Electrodes- It’s consists a coating factor
approximately 1.45. Example- Overcord-C, (A.O)
4. Heavy Coated Electrodes- It’s consists a coating factor
between 1.6 & 2.2. It produce a deeper penetration. Example-
Citofine (A.O).
Covered Electrode-
When molten metal is exposed to air, it absorbs oxygen and
nitrogen, and becomes brittle or is otherwise adversely
affected. A slag cover is needed to protect molten or
solidifying weld metal from the atmosphere. This cover can
be obtained from the electrode coating.
A Covered electrode consists of a flux material coated on the
core wire.

50. Manufacture Process of Electrodes-
There are two methods of applying flux coating on the core
wire
1. Dipping
2. Extrusion Process
1. Dipping Method- In this method core wire are cut into
definite length & clamp vertically in fixture & dipped in a
bath of molten flux. When a suitable thickness of the flux gets
adhered to the core wire, the fixture is raised & the flux is
allowed to dry.

51. 2. Extrusion Method- In this method coating ingredients are
mixed up in desired quantities, binder (sodium silicate) is
added & the resultant mass is brought in the form of a thick,
viscous, stiff paste.
 This paste is shaped in the form of a cylinder which is fed
into the extrusion press.
 The core wire & thick paste of flux simultaneously under
pressure pass though a die, thus attaching the flux coating
on the core wire. The gripping end of electrode is removed
by electrically rotate wire brush.

52. Flux ingredient & their Function
Flux Ingredient Primary Function Secondary
Cellulose Gas Generation
De-oxidation,
Strengthening coatings
Clay Slag Formation Arc Stability
Taic Slag Formation
Titanium Oxide
Arc Stability, Slag
Formation
Ilmenite Slag Formation Arc stability
Iron Oxide
Slag Formation,
Oxidation
Arc stability
Lime Carbonate Gas Generation
Arc stability,
Oxidation, Slag
formation

53. Flux Ingredient Primary Function
Secondary Function
Ferromanganese De-oxidation, Alloying Slag Formation
Manganese Dioxide Oxidation
Slag Formation
Silica Sand Slag Formation
Potassium Silicate
Binding Coatings, Arc
Stability, Slag
Formation
Sodium Silicate
Binding Coatings, Arc
Stability, Slag
Formation

54. Selection of Electrodes-
1. Chemical Composition of the base metal.
2. Thickness of the workpiece.
3. Nature of electrode coating (Cellulose, Rutile & low
hydrogen etc.) & metal losses due to volatilization & spatter.
4. Positions ( Flat, Horizontal, Vertical, Overhead) in which
welding is to be carried out.
5. Types of joint ( lap, butt, fillet etc.) & number of runs.
6. Types of power source ( AC or DC) Available.
7. Types of polarities (DCSP or DCRP).
8. Weld bead geometry & shape of the weld bead.
9. Surface finish & quality of weld metal.
10. Cost of the electrode.

55. Electrode Coding-
According to Indian (IS) System-
L X X X X X X L
1st 1st 2nd 3rd 4th 5th 6th Last
Letter Digits Letter
1st Letter – It can be E or R.
E= Solid extruded Electrode
R= Reinforcement extruded Electrode
1st Digit – It indicates the class of covering. It’s can be
1,2,3,4,5,6 or 9.

56. 1st Digit – It indicates the class of covering. It’s can be
1,2,3,4,5,6 or 9.
1= High Cellulose Content.
2= High Titania Content resulting fairly viscous slag.
3= Appreciable Titania Content resulting in a fluid slag.
4= High Iron & Mn Oxide or Silicates Contents resulting in
inflated slag.
5= High Iron & Mn Oxide or Silicates Contents resulting in a
heavy solid slag.
6= Highly calcium carbonate & fluoride content.
9= Any other types of covering.
2nd Digit – It indicates positions in which electrode can weld
satisfactory. It’s can be 0,1,2,3,4 or 9.

57. 0 & 1= All positions (Flat, Horizontal, Vertical & overhead)
2= Flat & horizontal.
3= Flat only.
4= Flat & Horizontal fillet positions.
9= Not Classified.
3rd Digit – It indicates the current, polarity & open circuit
voltage of welding power source. It’s can be 0,1,2,3,4,5,6,7,9.
0 = DC+ i.e. DCRP
1 = DC+, A90 i.e. DCRP or AC with OC voltage over 90
volts.
2 = DC-, A70
3 = DC-, A50
4 = DC+, A70

58. 5 = D± , A90
6 = D± , A70
7 = D± , A50
9 = Not Classified.
4th & 5th Digit – It indicates the range of tensile strength &
minimum yield strength.
6th Digit – It indicates the percentage elongation & impact
value.
Last Letter – It’s can be P,H,J,K or L.
P = Deep penetration electrode.
H = Hydrogen controlled electrode
J= Electrode powder coating & metal recovery 110-130%
K= Electrode powder coating & metal recovery 130-150%

59. L= Electrode powder coating & metal recovery more
than150%
Example- E307411P
E= Extruded electrode
3= Covering contains appreciable amount of Titania, a fluid
slag.
0= All position electrode.
7= DCSP, DCRP or AC power source with OC voltage 50.
4= Tensile strength 410 N/mm2 to 510 N/mm2
1= Minimum Yield strength 330 N/mm2
1=Minimum percentage elongation of weld metal is 20% of
5.65S0 where S0 is cross section area of specimen.
P= Deep penetration

61. “Hand shield is a protective device protecting the face & neck
of the operator. A hand shield in the hand of the welder &
equipped with a suitable filter lens.”
A hand shield is a type of welder’s mask hold in one hand.
Hand shields or helmets provide eye protection by using an
assembly of components:
1. Helmet shell - must be opaque to light and resistant to
impact, heat and electricity.
2. Outer cover plate- It’s made of polycarbonate plastic
which protects from radiation, impact and scratches.

63. 3. Filter lens- It’s made of glass containing a filler which
reduces the amount of light passing through to the eyes.
Filters are available in different shade numbers ranging from
2 to 14. The higher the number, the darker the filter and the
less light passes through the lens.
4. Clear retainer lens- It’s made of plastic prevents any
broken pieces of the filter lens from reaching the eye.
5. Gasket- It’s made of heat insulating material between the
cover lens and the filter lens protects the lens from sudden
heat changes which could cause it to break. In some models
the heat insulation is provided by the frame mount instead of
a separate gasket.

64. “Helmet is a protective device protecting the face, neck &
head of the operator & equipped with a suitable filter lens.”
Or
A welding helmet is a type of headgear used when performing
certain types of welding to protect the eyes, face and neck
from flash burn, ultraviolet light, sparks, infrared light, and
heat.
Welding helmets are most commonly used with arc welding
processes such as shielded metal arc welding, gas tungsten arc
welding, and gas metal arc welding. They are necessary to
prevent arc eye, a painful condition where the cornea is
inflamed. Welding helmets can also prevent retina burns,
which can lead to a loss of vision.

66.  The modern welding helmet used today was first
introduced in 1937 by Willson Products.
 Most welding helmets include a window covered with a
filter called a lens shade, through which the welder can see
to work.
 In most helmets, the window may be made of tinted glass,
tinted plastic, or a variable-density filter made from a pair
of polarized lenses.
 Different lens shades are needed for different welding
processes. For example MIG and TIG welding are low-
intensity processes, so a lighter lens shade will be
preferred.

67. Type of Welding Amperage Lens Shade
TIG – Mild Steel 5 to 20 Shade 9
TIG – Mild Steel 20 to 30 Shade 10
TIG – Mild Steel 30 to 100 Shade 11
TIG – Mild Steel 100 to 150 Shade 12
TIG – Mild Steel 150 to 250 Shade 13

68. Type of Welding Amperage Lens Shade
MIG –
Aluminium
80 to 100
Shade 10
MIG –
Aluminium
100 to 175 Shade 11
MIG –
Aluminium
175 to 250 Shade 12
MIG –
Aluminium
250 to 350 Shade 13

69. Type of Welding Amperage Lens Shade
MIG – Flux Core 125 to 175 Shade 10
MIG – Flux Core 175 to 225 Shade 11
MIG – Flux Core 225 to 275 Shade 12
MIG – Flux Core 275 to 350 Shade 13

70. Type of Welding Amperage Lens Shade
MIG – Mild
Steel
80 to 100 Shade 10
MIG – Mild
Steel
100 to 175 Shade 11
MIG – Mild
Steel
175 to 300 Shade 12
MIG – Mild
Steel
300 to 500 Shade 13

71. Type of Welding Amperage Lens Shade
Plasma Welding 10 to 15 Shade 9
Plasma Welding 15 to 30 Shade 10

75. The protective clothing protect the limbs of the welder against
burning by molten metal, molten flux spatters & sparks.”
The protective clothes are following types-
1. Apron
2. Gloves
3. Sleeves
4. Cape & Cap
5. Shoes
1. Apron- The apron provides protection to the clothes of the
welder. It’s made of chrome leather. It offer best protection
against hot spattering particles.

76. Welding Apron Welding Gloves

77. 2. Gloves- The gloves protect the hand of the welder from
ultraviolet rays & spattering hot metal. The gloves are
generally made of leather or a combination of cloth &
asbestos.
3. Sleeve- The sleeve is used for protecting the hands of the
welder.
4. Cape & Cap- The cape protect the shoulders & arms of the
welder & the cap is employed to protect the head & hair of
welder.
5. Shoes- The shoes are protect the feet of the welder from
dropping molten metals.

78. Welding Sleeves Welding Cape

79. Welding ShoesWelding Cap

81. “The weld bead cleaning accessories are generally used for
cleaning the weld bead.”
Following weld bead cleaning accessories are used-
1. Chipping Hammer
2. Wire Brush
1. Chipping Hammer- The chipping hammer is chisel shaped
& is pointed on one end to aid in the removal of slag from
over the weld bead.
2. Wire Brush- The wire brush made up of stiff steel wire
embedded in wood remove small particles of slag from weld
bead after the chipping hammer has done its job.

82. The wire brush also used to clean the surface of the base
metal of rust, oil scale, paint etc. before the welding operation
so that resulting welds are of good quality.

83. Welding Hammer Welding Wire Brush