The document discusses arc welding, including:
- Arc welding is commonly used to join metal pieces by creating an electric arc that melts and fuses the metals together. It involves an electrode, electric arc, and sometimes filler material.
- There are several types of arc welding processes including shielded metal arc welding, gas metal arc welding, gas tungsten arc welding, and others.
- Arc welding has advantages like efficiency and flexibility but also limitations like safety hazards, high labor costs, and difficulty detecting defects. Proper safety equipment and techniques are important when arc welding.
4. Why is Welding Important?
• Many things around us are welded …
– Pipelines that bring fresh water
– Towers that carry electricity to houses
– Cars and buses that take people where they need to
go
5. What is Arc Welding?
Arc welding is most commonly used to join two
pieces of metal
The welder creates an electric arc that melts the base
metals and filler metal (consumable) together so that
they all fuse into one solid piece of metal
Steel Pipe –
Tack Welded
Root Pass or
“Stringer Bead”
Final weld after several
beads are made
6. Basics of Arc Welding
The arc is struck between the electrode
and the metal. It then heats the metal to a
melting point. The electrode is then
removed, breaking the arc between the
electrode and the metal. This allows the
molten metal to “freeze” or solidify.
7. Basic Steps of Arc Welding
• Prepare the base materials: remove paint and rust
• Choose the right welding process
• Choose the right filler material
• Apply Safety requirements
• Use proper welding techniques and be sure to protect the molten
puddle from contaminants in the air
• Inspect the weld
11. Types of Arc Welding
Carbon arc
Metal arc
Metal inert gas
Tungsten inert gas
Plasma arc
Submerged arc
Electro-slag
12. Carbon Arc Welding
Carbon arc welding (CAW) is a process which produces
coalescence of metals by heating them with
an arc between a non-consumable carbon (graphite)
electrode and the work-piece.
13. Metal Arc Welding
Shielded metal arc welding (SMAW) is a manual arc
welding process that uses a consumable electrode
covered with a flux to lay the weld.
14. Metal & Tungsten Inert Arc
• Gas metal arc welding (GMAW), sometimes referred to by its
subtypes metal inert gas (MIG) welding is a welding process in
which an electric arc forms between a consumable wire electrode
and the work piece metal which heats the work piece metal causing
them to melt and join.
15. Plasma Arc Welding
• Plasma arc welding (PAW) is an arc welding process
similar to gas tungsten arc welding(GTAW). The
electric arc is formed between an electrode and the work
piece.
16. Submerged Arc Welding
• Submerged arc welding (SAW) is a common arc
welding process. The first patent on the
submerged-arc welding (SAW) process was
taken out in 1935 and covered an
electric arc beneath a bed of granulated flux.
17. Electro Slag Arc Welding
• Electro slag welding (ESW) is a highly
productive
• It is a single pass welding process for thick
(greater than 25 mm up to about 300 mm)
materials in a vertical or close to vertical
position.
18. Arc welding
Advantages
– Most efficient way to join
metals
– Lowest-cost joining method
– Inexpensive Power source
is used as domestic
electricity is compatible
– Joins all commercial
metals
– Provides design flexibility
Limitations
• Manually applied, therefore
high labor cost.
• Need high energy causing
danger
• Not convenient for
disassembly.
• Defects are hard to detect at
joints.
19. 19
Arc Welding Safety
• Protect yourself and others
from potential hazards
including:
Fumes and Gases
Electric Shock
Arc Rays
Fire and Explosion
Hazards
Noise
Hot objects