I made this ppt for the college presentation. I think this will help you to understand the basic.

1. ELECTRIC WELDING
SANJAY KUMAR

2. What is Electric Welding
▪ It is a process of joiningTwo pieces of metal
by the application of heat or pressure or both
andWith or without the use of filler Metal
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3. Welding
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4. RESITANCE WELDING
▪ The resistance of metal to
the localized flow of
current produces heat
▪ Process variables
– Current
– Time
– Force
▪ Spot ,seam ,Butt ,
projection welding
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5. Definition of Resistance welding
▪ Resistance welding is that
process in which a sufficient
current is sent through the two
metal piece in contact to the
welded metal. which melts the
metals by the resistance they
offer to the flow of the electric
current
▪ In resistance welding a heavy
current above 100A at a low
voltage 1 to12 volts is passed
directly through the two pieces
being welded & Heat
developed by the contact
resistance to the flow of
current.
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6. Advantage s of resistance welding
▪ Heat is localized where required.
▪ Welding action rapid.
▪ No filler material is needed.
▪ Requires comparatively lesser skill .
▪ Is suitable for large quantity production.
▪ Both similar & dissimilar metals can be welded.
▪ Difficult shapes & sections can be welded.
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7. Application of Resistance welding
▪ Automotive / auto industry
▪ Aerospace / airplane
▪ Electric / Electronics
▪ Radiator / Container
▪ Domestic hardware
▪ Medical instrument
▪ Nuclear equipment
▪ Food and drink
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8. Resistance spot Welding
Thermal Diagram Definition
▪ Spot welding is a resistance
welding process for joining
metal sheets by directly
applying opposing forces with
electrodes with pointed tips.
The current and the heat
generation are localized by the
form of the electrodes.The
weld nugget size is usually
defined by the electrode tip
contact area.
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9. Diagram of Spot Welding
Electrode
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10. Advantage of spot Welding
▪ Electrical spot welding are most widely used
▪ The cost is low
▪ The speed is high
▪ It can be easily performed by even a semi- skilled operator
▪ This process has a fast welding rate
▪ Quick set –up time
▪ Low unit cost per weld
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11. Resitance seam welding
▪ Seam welding is a resistance
welding process for joining
metal sheets in continuous,
often leak tight, seam joints by
directly applying opposing
forces with electrodes
consisting of rotary wheels.
The current and the heat
generation are localized by the
peripheral shapes of the
electrode wheels.
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12. Application of Seam Welding
Seam welding is mostly applied in manufacturing of containers,
radiators and heat exchangers etc.
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13. Resistance projection Welding
▪ Projection welding is a resistance welding
process for joining metal components or
sheets with embossments by directly
applying opposing forces with electrodes
specially designed to fit the shapes of the
workpieces.The current and the heat
generation are localized by the shape of the
workpieces either with their natural shape or
with specially designed projection. Large
deformation or collapse will occur in the
projection part of the workpieces implying
high process/machine dynamics.
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14. Application of Projection Welding
Projection welding is widely used in electrical, electronics, automotive and
construction industries, and manufacturing of sensors, valves and pumps etc.
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15. Resitance Butt welding
▪ Butt welding is a resistance welding process for joining thick metal
plates or bars at the ends by directly applying opposing forces with
electrodes clamping the workpieces. A forging operation is applied
after the workpieces are heated up. Often no melt occurs, thus a solid
state weld can be obtained.
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16. Arc welding
▪ The arc welding is a fusion welding process in which the heat
required to fuse the metal is obtained from an electric arc between
the base metal and an electrode.
▪ The electric arc is produced when two conductors are touches
together and then separated by a small gap of 2 to 4 mm, such that
the current continues to flow, through the air.The temperature
produced by the electric arc is about 4000°C to 6000°C.
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17. Electron Beam welding
▪ In an electron beam welder electrons
are "boiled off" as current passes
through a filament which is in a vacuum
enclosure. An electrostatic field,
generated by a negatively charged
filament and bias cup and a positively
charged anode, accelerates the
electrons to about 50% to 80% of the
speed of light and shapes them into a
beam. Due to the physical nature of the
electrons - charged particles with an
extremely low mass - their direction of
travel can easily be influenced by
electromagnetic fields. Electron beam
welders use this characteristic to
electromagnetically focus and very
precisely deflect the beam at speeds up
to 10 kHz. Recent machine
developments make it possible even to
go up to 200 kHz.
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18. Application of Beam Welding
▪ It is used in aerospace
industries and marine
industries for structure work
▪ It is used to join titanium and
its alloy.
▪ It is used to weld electronic
connectors in electronic
industries.
▪ This process is also used in
nuclear reactors and in medical
industries
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19. Laser Welding
▪ Laser beam welding (LBW) is a welding technique used to join
multiple pieces of metal through the use of a laser.The beam
provides a concentrated heat source, allowing for narrow, deep welds
and high welding rates.
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20. Laser Beam welding (LBW)
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21. Application of laser Beam welding (LBW)
▪ Laser is a high energy light beam that can both weld and cut the
metals.
▪ Laser is a high energy light beam that can both weld and cut the
metals.
▪ To weld lead wires having polyurethane insulation without removing
the insulation.The laser evaporates the insulation and completes the
weld.
▪ To join hard high melting point metal alloys.
▪ In space and aircraft industry for welding light gauge materials.
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