Introduction to welding

Introduction to Welding
Er. Mani Das
Civil Engineer
TJSS (CTEVE)
9866019982
1

Introduction to welding
Welding is a fabrication or sculptural
process that joins materials, usually metals
or thermoplastics, by using high heat to
melt the parts together and allowing them
to cool causing fusion.
4 Popular Types of Welding Procedures
• Shielded Metal Arc Welding (SMAW) With
this particular type of welding, the
welder follows a manual process of stick
welding. ...
• Gas Metal Arc Welding (GMAW/MIG) This
style of welding is also referred to as
Metal Inert Gas (MIG). ...
• Flux Cored Arc Welding (FCAW) ...
• Gas Tungsten Arc Gas Welding
(GTAW/TIG)
2

Arc welding
Arc welding is a welding process
that is used to join metal to metal
by using electricity to create
enough heat to melt metal, and the
melted metals when cool result in a
binding of the metals. It is a type of
welding that uses a welding power
supply to create an electric
arc between a metal stick
("electrode") and the base material
to melt the metals at the point-of-
contact. Arc welders can use
either direct (DC) or alternating(AC)
current, and consumable or non-
consumable electrodes.
3

Electric power needed for welding
SAFETY ELEMENTARY ARC WELDINGP
the type of electric welders most likely
to be used will be the 240 volt a.c
machine, which is capable of an output
current of 130 amperes with a voltage
across the arc of approximately 24
volts. These machines are potential
source of electric shock, which can kill
All welding machines electric welding
leads and fittings are to be checked or
tested every four month by a certified
electrician who shall fix a metal tag
consisting of date showing when next
inspection is due.
4

Welding rods
The welding rod is the piece of wire
connected to the welding machine.
A current is fed through this wire,
which helps to join two pieces of
metal together firmly.
In the field, welding electrodes are
usually referred to as "welding rods"
so It will use that term here.
"Stick Welding" is also the term of
choice in the field for SMAW, the
acronym for Shielded Metal
Arc Welding. Stick welding used to
be done with a bare welding rod.
5

Welding rods
4 Different Types of Welding Rods
• 6010 arc welding rods are most commonly used for welding root passes in pipe and even
for the fill passes on pipelines.
• 6013 arc welding rods are the farmers welding rod and the welding rodmost people use
first when learning to weld.
• 7018. This is a very versatile type of welding rod and is a little easier to use than 6010. ...
• 308L AC/DC. This rod is used to weld stainless steel and is resistant to cracks and corrosion.
...
• 24 AC/DC.
6

Welding safety rules
Basics
ALWAYS wear a proper face shield (Helmet).
ALWAYS wear close-toed shoes (Leggings).
Light rays may cause injury by burning the exposed body parts of
the body so ALWAYS wear a long-sleeved, non-flammable shirt
(Apron).
ALWAYS wear proper welding gloves.
The fume from material such as zinc(galvanizing) tin, brass and
lead are toxic to breath, Thus mask is mandatory,
ALWAYS wear ear protection (earplugs or muffs) to prevent sparks
from entering your ear canal.
Keep all flammable material far from welding area sucg as
petroleum products.
Know where the fire extinguisher is located.
7

Arc welding equipment’s, accessories and
protective gear
The various equipments required for
electric arc welding are:
Welding Machine: The welding machine
used can be A.C. or D.C. welding
machine. ...
Electrode Holders: ...
Cables or Leads: ...
Cable Connectors and Lugs: ...
Chipping Hammer: ...
Wire Brush, Power Wire Wheel: ...
Protective Clothing: ...
Screen or Face Shield:
8

Arc welding equipment’s, accessories and
protective gear
The various equipments required for electric arc welding are:
• WELDING CABLE MARIGASES WELDING CABLE is black neoprene sheathed cable, with high f`ity and copper
conductor. Highly resistant to oil, water, flame and abrasion. It is available in cross section areas 50 and 70mm².
• CABLE CONNECTORS MARIGASES CABLE CONNECTORS ensure good electrical conductivity and are suitable for use with
either copper or aluminium cable, providing a quick, watertight fitting of cables on sight. The connector is distinguished
into two part as Male and female connectors.
• ELECTRODE HOLDERS & GROUND CLAMPS have knurled (पेच कस्न मिल्ने) handle providing a firm grip and good balance.
Designed to withstand heat, with shielded spring to prevent damage from spatter and fixing by means of a bolt.
• FACE SHIELDS
• PROTECTIVE CLOTHING is made from specially treated soft leather to ensure maximum safety and comfort. They provide
full protection against heat, falling sparks and slag, under the toughest conditions.
• WIRE BRUSH Ideal for cleaning before welding and also de– slagging.
9

Types of Welding
Different types of welding and what they are used for
MIG Welding. MIG welding is one of the easier types of welding for beginners to learn. ...
Stick Welding. Stick welding, also known as Arc welding, is doing it the old fashioned way. ...
TIG Welding: Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an
arc welding process that uses a non-consumable tungsten electrode to produce the weld. Plasma Arc
Welding. ...
Electron Beam and Laser Welding. ...
Gas Welding.
10
Stainless steel TIG welding

Laser beam welding
Laser beam welding is a welding
technique used to join pieces of
metal or thermoplastics through
the use of a laser. The beam
provides a concentrated heat
source, allowing for narrow, deep
welds and high welding rates. The
process is frequently used in high
volume applications
using automation, such as in the
automotive industry. It is based on
keyhole or penetration mode
welding.
12

Gas Welding
Oxy-fuel welding (commonly called oxyacetylene
welding, oxy welding, or gas welding in the U.S.)
and oxy-fuel cutting are processes that use fuel
gases and oxygen to weld and cut metals,
respectively. French engineers Edmond Fouché and
Charles Picard became the first to develop oxygen-
acetylene welding in 1903.[1] Pure oxygen, instead
of air, is used to increase the flame temperature to
allow localized melting of the workpiece material
(e.g. steel) in a room environment.
13

Welding Technique 14
Weld Types and techniques

Principle of gas welding
What is principle of gas welding?
Principle: Gas welding is a most
important type of welding process. It is
done by burning of fuel gases with the
help of oxygen which forms a
concentrated flame of high
temperature. This flame directly strikes
the weld area and melts
the weldsurface and filler material.
16

Forge welding
Forge welding (FOW) is a solid-state welding process[1] that
joins two pieces of metal by heating them to a high
temperature and then hammering them together.[2] It may also
consist of heating and forcing the metals together with presses
or other means, creating enough pressure to cause plastic
deformation at the weld surfaces.[3] The process is one of the
simplest methods of joining metals and has been used since
ancient times. Forge welding is versatile, being able to join a
host of similar and dissimilar metals. With the invention of
electrical and gas welding methods during the Industrial
Revolution, manual forge-welding has been largely replaced,
although automated forge-welding is a common manufacturing
process.
Many metals can be forge welded, with the most common
being both high and low-carbon steels. Iron and even
some hypoeutectic cast-irons can be forge welded.
Some aluminum alloys can also be forge welded.[13] Metals such
as copper, bronze and brass do not forge weld readily
17

Introduction to welding

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