Puneet Manufacturing Sciences(Term Paper)

8/3/2019 Puneet Manufacturing Sciences(Term Paper)

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SUBMITTED BY: - SUBMITTED TO:-

Name PUNEET Mr.HIMANSHU PAYAL

Regd. NO-10904420

Section: RM4901Roll no: A21


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ACKNOWLEDGEMENT

I express my gratefulness to the department of MANUFACTURING SCIENCES

for support. I further would like to sincerely and wholeheartedly thank Mr.

HIMANSHU PAYAL ,faculty,MANUFACTURING SCIENCES ,Lovely

Professional University, for his valuable guidance and for giving me a chance to

undertake this term paper. A special word of thank should go to all the faculties of

physics for providing the resources and guidance to execute the project work

successfully. My family too has all my gratitude due for their ever required

encouragement, support and valuable suggestions to improve my work. Last but

not the least I thank all my friends and colleagues for helping me throughout the

work directly or indirectly.


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CONTENTS

ACKNOWLEDGEMENT

INTROCUCTION

HISTORY

LITERARY SERVAE

REVIEW AND DISCUSSION


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INTRODUCTION

Welding, an integral part of fabrication process consists of merging of two or more

metals by melting and subsequent cooling. One has to exercise proper safety norms

while carrying out welding.Welding is a technique used in the fabrication process

mostly. The method involves metals, materials etc. The act of welding relates to

merging of two particles in to one, by the melting and cooling processes. The

heating in the welding can be done by a gas flame, electric arc, laser, electron

beam, friction and ultra sound. The actual procedure of welding can be carried out

in open air, underwater and in space. But wherever it is done, welding remains to

be more dangerous. Unless proper precautions are taken, the welding person may

be exposed to burns, electric shock, deadly fumes and ultraviolet rays.

Many different energy sources can be used for welding, including a gas flame, an

electric arc, a laser, an electron beam, friction, and ultrasound. While often an

industrial process, welding can be done in many different environments, including

open air, under waterand in outer space. Regardless of location, however, welding

remains dangerous, and precautions are taken to avoid burns, electric shock, eye

damage, poisonous fumes, and overexposure to ultraviolet light.
http://en.wikipedia.org/wiki/Energy_sourcehttp://en.wikipedia.org/wiki/Firehttp://en.wikipedia.org/wiki/Electric_archttp://en.wikipedia.org/wiki/Laserhttp://en.wikipedia.org/wiki/Electron_beam_weldinghttp://en.wikipedia.org/wiki/Friction_Weldinghttp://en.wikipedia.org/wiki/Ultrasoundhttp://en.wikipedia.org/wiki/Underwater_weldinghttp://en.wikipedia.org/wiki/Outer_spacehttp://en.wikipedia.org/wiki/Electric_shockhttp://en.wikipedia.org/wiki/Ultraviolet_lighthttp://en.wikipedia.org/wiki/Energy_sourcehttp://en.wikipedia.org/wiki/Firehttp://en.wikipedia.org/wiki/Electric_archttp://en.wikipedia.org/wiki/Laserhttp://en.wikipedia.org/wiki/Electron_beam_weldinghttp://en.wikipedia.org/wiki/Friction_Weldinghttp://en.wikipedia.org/wiki/Ultrasoundhttp://en.wikipedia.org/wiki/Underwater_weldinghttp://en.wikipedia.org/wiki/Outer_spacehttp://en.wikipedia.org/wiki/Electric_shockhttp://en.wikipedia.org/wiki/Ultraviolet_light


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History

The iron pillar of Delhi

The history of joining metals goes back several millennia, with the earliest

examples of welding from the Bronze Age and the Iron Age in Europe and the

Middle East. Welding was used in the construction of the iron pillarin Delhi, India,

erected about 310 AD and weighing 5.4 metric tons.

The Middle Ages brought advances in forge welding, in which blacksmiths

pounded heated metal repeatedly until bonding occurred. In 1540, Vannoccio

Biringuccio publishedDe la pirotechnia, which includes descriptions of the

forging operation. Renaissance craftsmen were skilled in the process, and the

industry continued to grow during the following centuries. Welding, however, was

transformed during the 19th century. In 1802, Russian scientist Vasily Petrov

discovered the electric arc and subsequently proposed its possible practical

appplications, including welding. In 1881-82 a Russian inventorNikolai Bernardos

created the first electric arc welding method known as carbon arc welding, usingcarbon electrodes. The advances in arc welding continued with the invention of

metal electrodes in the late 1800s by a Russian,Nikolai Slavyanov (1888), and an

American, C. L. Coffin. Around 1900, A. P. Strohmengerreleased a coated metal

electrode in Britain, which gave a more stable arc. In 1905 Russian scientist

Vladimir Mitkevich proposed the usage of three-phase electric arc for welding. In
http://en.wikipedia.org/wiki/Iron_pillar_of_Delhihttp://en.wikipedia.org/wiki/Bronze_Agehttp://en.wikipedia.org/wiki/Iron_Agehttp://en.wikipedia.org/wiki/Europehttp://en.wikipedia.org/wiki/Middle_Easthttp://en.wikipedia.org/wiki/Iron_pillar_of_Delhihttp://en.wikipedia.org/wiki/Delhihttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Metric_tonshttp://en.wikipedia.org/wiki/Middle_Ageshttp://en.wikipedia.org/wiki/Forge_weldinghttp://en.wikipedia.org/wiki/Vannoccio_Biringucciohttp://en.wikipedia.org/wiki/Vannoccio_Biringucciohttp://en.wikipedia.org/wiki/De_la_pirotechniahttp://en.wikipedia.org/wiki/Renaissancehttp://en.wikipedia.org/wiki/Vasily_Vladimirovich_Petrovhttp://en.wikipedia.org/wiki/Electric_archttp://en.wikipedia.org/wiki/Electric_archttp://en.wikipedia.org/w/index.php?title=Nikolai_Bernardos&action=edit&redlink=1http://en.wikipedia.org/wiki/Carbon_arc_weldinghttp://en.wikipedia.org/w/index.php?title=Nikolai_Slavyanov&action=edit&redlink=1http://en.wikipedia.org/wiki/C._L._Coffinhttp://en.wikipedia.org/w/index.php?title=A._P._Strohmenger&action=edit&redlink=1http://en.wikipedia.org/wiki/United_Kingdomhttp://en.wikipedia.org/w/index.php?title=Vladimir_Mitkevich&action=edit&redlink=1http://en.wikipedia.org/wiki/File:QtubIronPillar.JPGhttp://en.wikipedia.org/wiki/Iron_pillar_of_Delhihttp://en.wikipedia.org/wiki/Bronze_Agehttp://en.wikipedia.org/wiki/Iron_Agehttp://en.wikipedia.org/wiki/Europehttp://en.wikipedia.org/wiki/Middle_Easthttp://en.wikipedia.org/wiki/Iron_pillar_of_Delhihttp://en.wikipedia.org/wiki/Delhihttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Metric_tonshttp://en.wikipedia.org/wiki/Middle_Ageshttp://en.wikipedia.org/wiki/Forge_weldinghttp://en.wikipedia.org/wiki/Vannoccio_Biringucciohttp://en.wikipedia.org/wiki/Vannoccio_Biringucciohttp://en.wikipedia.org/wiki/De_la_pirotechniahttp://en.wikipedia.org/wiki/Renaissancehttp://en.wikipedia.org/wiki/Vasily_Vladimirovich_Petrovhttp://en.wikipedia.org/wiki/Electric_archttp://en.wikipedia.org/w/index.php?title=Nikolai_Bernardos&action=edit&redlink=1http://en.wikipedia.org/wiki/Carbon_arc_weldinghttp://en.wikipedia.org/w/index.php?title=Nikolai_Slavyanov&action=edit&redlink=1http://en.wikipedia.org/wiki/C._L._Coffinhttp://en.wikipedia.org/w/index.php?title=A._P._Strohmenger&action=edit&redlink=1http://en.wikipedia.org/wiki/United_Kingdomhttp://en.wikipedia.org/w/index.php?title=Vladimir_Mitkevich&action=edit&redlink=1


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1919, alternating current welding was invented by C. J. Holslag but did not become

popular for another decade.

Resistance welding was also developed during the final decades of the 19th

century, with the first patents going toElihu Thomson in 1885, who produced

further advances over the next 15 years. Thermite welding was invented in 1893,

and around that time another process, oxyfuel welding, became well established.

Acetylene was discovered in 1836 by Edmund Davy, but its use was not practical

in welding until about 1900, when a suitableblowtorch was developed. At first,

oxyfuel welding was one of the more popular welding methods due to its

portability and relatively low cost. As the 20th century progressed, however, it fell

out of favor for industrial applications. It was largely replaced with arc welding, as

metal coverings (known as flux) for the electrode that stabilize the arc and shield

the base material from impurities continued to be developed.
http://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/w/index.php?title=C._J._Holslag&action=edit&redlink=1http://en.wikipedia.org/wiki/Resistance_weldinghttp://en.wikipedia.org/wiki/Elihu_Thomsonhttp://en.wikipedia.org/wiki/Elihu_Thomsonhttp://en.wikipedia.org/wiki/Exothermic_weldinghttp://en.wikipedia.org/wiki/Oxy-fuel_welding_and_cuttinghttp://en.wikipedia.org/wiki/Acetylenehttp://en.wikipedia.org/wiki/Edmund_Davyhttp://en.wikipedia.org/wiki/Gas_weldinghttp://en.wikipedia.org/wiki/Flux_(metallurgy)http://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/w/index.php?title=C._J._Holslag&action=edit&redlink=1http://en.wikipedia.org/wiki/Resistance_weldinghttp://en.wikipedia.org/wiki/Elihu_Thomsonhttp://en.wikipedia.org/wiki/Exothermic_weldinghttp://en.wikipedia.org/wiki/Oxy-fuel_welding_and_cuttinghttp://en.wikipedia.org/wiki/Acetylenehttp://en.wikipedia.org/wiki/Edmund_Davyhttp://en.wikipedia.org/wiki/Gas_weldinghttp://en.wikipedia.org/wiki/Flux_(metallurgy)


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LITERARY SERVAE

WIKIPEDIA

GOOGLE BOOK


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REVIEW AND DISCUSSION

There are many different types of welding that you can use to join materials

together. I'm going to be talking about the welding of metal to metal and steel to

steel.

The most common forms welding are:

Wire feed welding - which some people describe as mig, mag, gasless or

flux cored.

Arc welding - also known as stick welding

Tig welding -

Gas welding

Spot welding

MIG WELDING:

MIG (Metal Inert Gas) or as it even is called GMAW (Gas Metal Arc Welding)

uses an aluminium alloy wire as a combined electrode and filler material. The filler

metal is added continuously and welding without filler-material is therefore notpossible. Since all welding parameters are controlled by the welding machine, the

process is also called semi-automatic welding.

The MIG-process uses a direct current power source, with the electrode positive

(DC, EP). By using a positive electrode, the oxide layer is efficiently removed

from the aluminium surface, which is essential for avoiding lack of fusion and


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oxide inclusions. The metal is transferred from the filler wire to the weld bead by

magnetic forces as small droplets spray transfer. This gives a deep penetration

capability to the process and makes it possible to weld in all positions. It is

important for the quality of the weld that the spray transfer is obtained.

There are two different MIG-welding processes, conventional MIG and pulsed

MIG:

Conventional MIG uses a constant voltage DC power source. Since the spray

transfer is limited to a certain range of arc current, the conventional MIG process

has a lower limit of arc current (or heat input). This also limits the application of

conventional MIG to weld material thicknesses above 4 mm. Below 6 mm it is

recommended that backing is used to control the weld bead.

Pulsed MIG uses a DC power source with superimposed periodic pulses of highcurrent. During the low current level the arc is maintained without metal transfer.

During the high current pulses the metal is transferred in the spray mode. In this

way pulsed MIG is possible to operate with lower average current and heat input

compared to conventional MIG. This makes it possible to weld thinner sections and

weld much more easily in difficult welding positions.


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ARC WELDING

Arc welding is a process utilizing the concentrated heat of an electric arc to join

metal by fusion of the parent metal and the addition of metal to joint usuallyprovided by a consumable electrode. Either direct or alternating current may be

used for the arc, depending upon the material to be welded and the electrode used.

TYPES OF ARC WELDING:


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1.Fluxed-Core Arc-Welding

Fluxed-Core Arc-Welding uses a tubular electrode filled with flux that is much

less brittle than the coatings on SMAW electrodes while preserving most of its

potential alloying benefits.The emissive fluxes used shield the weld arc from

surrounding air, or shielding gases are used and nonemissive fluxes are employed.

The higher weld-metal deposition rate of FCAW over GMAW (Gas Metal Arc

Welding) has led to its popularity in joining relatively heavy sections of 1" or

thicker.

Another major advantage of FCAW is the ease with which specific weld-metal

alloy chemistries can be developed. The process is also easily automated,

especially with the new robotic systems.

2. Gas Metal-Arc Welding

Gas Metal-Arc Welding (GMAW), also called Metal Inert Gas (MIG) welding,

shields the weld zone with an external gas such as argon, helium, carbon dioxide,

or gas mixtures. Deoxidizers present in the electrode can completely prevent

oxidation in the weld puddle, making multiple weld layers possible at the joint.

GMAW is a relatively simple, versatile, and economical welding apparatus to use.This is due to the factor of 2 welding productivity over SMAW processes. In

addition, the temperatures involved in GMAW are relatively low and are therefore

suitable for thin sheet and sections less than inch.GMAW may be easily

automated, and lends itself readily to robotic methods. It has virtually replaced

SMAW in present-day welding operations in manufacturing plants.

3.Gas Tungsten-Arc WeldingGas Tungsten-Arc Welding (GTAW), also known as Tungsten Inert Gas or TIG

welding, uses tungsten electrodes as one pole of the arc to generate the heat

required. The gas is usually argon, helium, or a mixture of the two. A filler wire

provides the molten material if necessary.


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The GTAW process is especially suited to thin materials producing welds of

excellent quality and surface finish. Filler wire is usually selected to be similar in

composition to the materials being welded.Atomic Hydrogen Welding (AHW) is

similar and uses an arc between two tungsten or carbon electrodes in a shielding

atmosphere of hydrogen. Therefore, the work piece is not part of the electrical

circuit.

4.Plasma Arc WeldingPlasma Arc Welding (PAW) uses electrodes and ionized gases to generate an

extremely hot plasma jet aimed at the weld area. The higher energy concentration

is useful for deeper and narrower welds and increased welding speed.

TIG WELDING


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TIG-welding (Tungsten Inert Gas) or GTAW-welding (Gas Tungsten Arc

Welding) uses a permanent non-melting electrode made of tungsten. Filler metal is

added separately, which makes the process very flexible. It is also possible to weld

without filler material.

The most used power source for TIG-welding generates alternating current (AC).

Direct current can be used, but due to high heat generation on the tungsten

electrode when DC-EP (electrode positive) welding, that particular polarity is notfeasible. In some cases DC-EN (electrode negative) is used, however, this requires

special attention before welding, due to the arc's poor oxide cleaning action.

AC TIG-welding usually uses argon as a shielding gas. The process is a multi

purpose process, which offers the user great flexibility. By changing the diameter

of the tungsten electrode, welding may be performed with a wide range of heat


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input at different thicknesses. AC TIG-welding is possible with thicknesses down

to about 0,5 mm. For larger thicknesses, > 5 mm, AC TIG-welding is less

economical compared to MIG-welding due to lower welding speed.

DC TIG-welding with electrode negative is used for welding thicknesses above 4

mm. The negative electrode gives a poor oxide cleaning compared to AC-TIG and

MIG, and special cleaning of joint surfaces is necessary. The process usually uses

helium shielding gas. This gives a better penetration in thicker sections. DC TIG-

welding is applicable for welding thicknesses in the range 0,3 - 12 mm. More and

more popular is also pulsed DC TIG-welding, which makes it possible to weld

uniform welds with deeper penetration at the same heat input. Pulse frequency is

usually in the range 1 - 10 HZ

SPOT WELDING


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Spot welding is a process in which contacting metal surfaces are joined by the heat

obtained from resistance to electric current flow. Work-pieces are held together

under pressure exerted by electrodes. Typically the sheets are in the 0.5-3.0 mm

thickness range. The process uses two shaped copperalloyelectrodes to

concentrate welding current into a small "spot" and to simultaneously clamp thesheets together. Forcing a large current through the spot will melt the metal and

form the weld. The attractive feature of spot welding is a lot of energy can be

delivered to the spot in a very short time (ten to one hundred millisecond). That

permits the welding to occur without excessive heating to the rest of the sheet.

The amount of heat (energy) delivered to the spot is determined by the resistance

between the electrodes and the amplitude and duration of the current. The amount

of energy is chosen to match the sheet's material properties, its thickness, and type

of electrodes. Applying too little energy won't melt the metal or will make a poorweld. Applying too much energy will melt too much metal and make a hole rather

than a weld. Another attractive feature of spot welding is the energy delivered to

the spot can be controlled to produce reliable welds.
http://en.wikipedia.org/wiki/Copperhttp://en.wikipedia.org/wiki/Alloyhttp://en.wikipedia.org/wiki/Electrodehttp://en.wikipedia.org/wiki/Copperhttp://en.wikipedia.org/wiki/Alloyhttp://en.wikipedia.org/wiki/Electrode

Puneet Manufacturing Sciences(Term Paper)

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