Arc welding-Electric Arc Welding and its types .ppt

Arc welding, electricity, types of arc welding

1. ELECTRIC ARC WELDINGELECTRIC ARC WELDING
November 25, 2024 1Electric Arc Welding and its types.

2. Arc Welding- Definition
Arc Welding is the process in which the pieces of metal to be
welded are brought to the proper welding temperature at point
of contact by the heat liberated at the arc terminals.
Due to the arc formation, the metals are completely fused with
each other.
Single solid homogenous mass, after it solidifies.
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No mechanical pressure is applied in this type of welding.
This type of welding is also known as “Non –Pressure
Welding.”
The electrodes provides filler material to the weld and gets
consumed in the process.
The temperature of the arc is of the order of 3600
o
C.
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The arc voltage ranges from 20 V to 40 V.
The current in the range of 50 A to 1000 A.
This type of welding is widely used.
The Supply voltage is both AC and DC.
AC Supply Voltage is provided by Welding Transformer.
DC Supply is produced from Motor – Generator set.
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5. Arc Welding
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6. Electric Arc Welding- Types
Metal Arc Welding
Carbon Arc Welding
Atomic Hydrogen Arc Welding
Inert gas Metal arc Welding
Submerged Arc Welding.
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7. 1.1. METAL ARC WELDINGMETAL ARC WELDING
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8. Metal Arc Welding - Diagram
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9. Metal Arc Welding - Working
Arc is established between filler metal electrode and work piece.
The arc generates intense heat between filler metal electrode and
work piece.
It melts the metal and filler metal electrodes.
Used for Welding ferrous metal (sheet steel, low carbon steel, high
alloy stainless steel) and non-ferrous metals (brass, bronze and
Copper Alloy).
Both AC Supply and DC Supply are used for the Welding.
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DC Supply is used for welding both ferrous metals and non-ferrous
metals.
AC Supply is used for welding only ferrous metals.
Arc is struck with a Voltage of 60 V.
About 15 to 25 V is required to maintain the arc.
The Current required varies from 10 A to 500 A.
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11. 2. CARBON ARC WELDING2. CARBON ARC WELDING
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12. Carbon Arc Welding - Diagram
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13. Carbon Arc Welding - Working
Uses carbon or Graphite electrode.
Length is 300 mm and Diameter is 2.5 to 12 mm.
The carbon or graphite electrode is connected to Positive
supply.
The work piece is connected to Negative supply.
Arc is formed between electrode and the metal.
Filler rod is used to be more solidified.
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Positive electrode have 3900
o
C.
Negative electrode have 3200
o
C.
Usually graphite electrodes are used due to longer life and low
resistance.
The Voltage required for striking an arc is 30 V (with AC) and 40 V
(with DC).
The Current can go up to 800 A.
Used for welding galvanized sheets, Nickel alloys and stainless steel.
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15. 3. ATOMIC HYDROGEN ARC 3. ATOMIC HYDROGEN ARC
WELDINGWELDING
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16. Atomic Hydrogen Arc Welding - Diagram
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17. Atomic Hydrogen Arc Welding - Working
Arc is initiated between tungsten electrode and work piece.
Hydrogen gas is passed through the arc region.
The heat produced by the tungsten electrodes causes the
molecules of hydrogen to dissociate into atomic state.
This atomic hydrogen absorb considerable amount of heat.
These atomic hydrogen again combine outside the arc
resulting in generation of intense heat.
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This causes the arc temperature to reach about 4000
o
C.
The generation of high temperature due to the presence of hydrogen
gas speeds up the welding process.
This process is suitable for welding aluminium alloys, Chrome –
Nickel steel, tools and die repair, light alloy casting etc.,
Due to the confinement of arc in a small area, this method of welding
is extremely suitable for welding of thin sheets and welding of tubes.
Hydrogen required for the process is supplied through cylinder.
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19. 4. INERT GAS METAL ARC 4. INERT GAS METAL ARC
WELDINGWELDING
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20. Inert Gas Arc Welding - Diagram
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21. Inert Gas Arc Welding - Working
Having a gas shield of Helium gas or Argon gas.
An electric arc is produced by a consumable electrode and a filler
metal is fed continuously.
Helium gas or Argon gas is continuously blown through a nozzle into
the arc region.
Argon arc welding process requires lesser voltage compared to Helium
arc welding.
Argon arc welding is suitable for welding of thin cross-section sheets.
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Helium arc welding is used to weld thicker cross section
materials.
Mixture of both gases are also used to obtain intermediate
characteristics.
This process is used for welding Copper and Copper alloys,
aluminium and aluminium alloys, stainless steel, mild steel etc.,
Both AC supply and DC supply are used for the welding process.
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23. 55. SUBMERGED ARC WELDING. SUBMERGED ARC WELDING
November 25, 2024 23Electric Arc Welding and its types.

24. Submerged Arc Welding - Diagram
November 25, 2024 24Electric Arc Welding and its types.

25. Submerged Arc Welding - Working
Arc is produced between electrode and work piece.
Electric arc is produced inside the shield .
Cover of flux is laid along the seam to be welded.
The arc melts the electrode and metal piece.
The flux forms a slag that floats over the surface of molten forming a
protective layer.
The flux is made of metal oxides or silica.
This is an automated welding process in which electrode is fed through a
reel.
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Voltage used is 25 V to 40 V.
Current is up to 1000 A.
Suitable for welding stainless steel, low carbon steel, Nickel, Copper,
Monel etc.,
Can weld thick cross section with high strength and ductility.
Used to weld curved path or irregular path.
Used for welding pressure vessels, boilers and structural shapes etc.,
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