Quotes of the DAY

વહેલી પ્રભાત ના નાદ કરતા 

 એ પંખીડા ને અભિનંદન..........

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એ વ્યક્તિ ને અભિનંદન........!!!!!!

પ્રાણ આપી શાહિદ થનારા।.............

એ વીર ને અભિનંદન ............

પરંતુ એ પહેલા એ અભિનંદન ને 

બનાવનાર માતા ને કરોડો વંદન।...........;

Hardening and Tempering

Hardening and Tempering

Hardening is process in which steel is heated to a temperature above the
critical point, held at this temperature and quenched (rapidly cooled) in
water, oil or molten salt baths.
As earlier mentioned that if a piece of steel is heated above its upper
critical temperature and plunged into water to cool it an extremely hard,
needle-shaped structure known as martensite is formed. In other words,
sudden quenching of steel greatly increases its hardness.

After hardening steel must be tempered to:

1.reduce a brittleness,
2.reliev e the internal stresses, and
3.obtain pre-determined mechanical properties.
The hardening process is based on a very important metallurgical reaction
of decomposition of eutectoid.

This reaction is dependent upon the
following factors:
1.Adecuate carbon content to produce hardening.
2.Austenite decomposition to produce pearlite , bainite and martensite
structures.
3.Heating rate and time.
4.Quenching medium.
5.Quenching rate.
6.Size of the part.
7.Surface conditions.

 The rapidly with which the heat is absorbed by the quenching bath
has a considerable effect on the hardness of the metal. Clear, cold
water is very oftenly used, while the addition of salt still increases
degree of hardness.oil, however , gives the best balance between
hardness toughness and distortion for standard steels.

 In order to increase the cooling rate the parts may be moved around
the quenching bath, either by hand, or by passing them through the
tank in basket attached to mechanical conveyer. Large parts may be
lowered into the tank by a crane and kept moving while cooling.
It is often cheaper and more efficient, however , to circulate the
cooling liquid around the hot part.

 The heating rate and heating time depend on the composition of the
steel, its structure, residual stresses, the form and size of the part to
be hardened, the more the intricate and large the part being
hardened, the slower it should be heated to avoid stresses due to
temperature differences between the internal and external layers of
the metal, warping, and even cracking. The practically attainable
heating rate depends upon the thermal capacity of the furnace, the
bulk of the changed parts, their arrangement in the furnace, and
other factors. The heating rate is usually reduced, not by reducing
the furnace temperature but by preheating the articles.

 The heating time for carbon tool steels and medium-alloy
structural steels should be from 25 to 30% more than for carbon
structural steels. The heating time for high-alloy structural and tool
steels should be from 50 to 100% higher.
 When steel is exposed to an oxidizing atmosphere, because of the
presence of water vapor or oxygen in the furnace, a layer of iron
oxide called (scale) is formed. Thin layer of scale has very little
effect on cooling rate, but that a thick layer of oxide (0.005 in.
deep) retord the actual cooling rate.

Quenching media
The quenching media in general use are :
Water, Brine, Oils, Air, Molten salt.
Water : it is probably the most widely used as it simple and effective, it
cools at the rate of 982°C per second. It tends, however, to form bubbles
on the surface of the metal being quenched an causes soft spots, so a
brine solution is often used to prevent this trouble.


Brine :
 it is very rapid cooling agent and may tend to cause distortion of
the parts , as will water.
Oil : it is used when there is any risk of distortion although it is more
suitable for alloy steels than plain carbon steels.
Air blast : when the risk of distortion is great, quenching must be carried
out air blast. Since the rate of cooling is then lower, more hardening
elements must be added to the steel , forming an air-hardening alloy. The
air blast must be dry, since any moisture in the air will crack the steel.

Molten salts :
high speed steels are often quenched in molten salt to
hardened them.
Note : hypo-eutectoid steel containing very little carbon, say less than
0.25%, cannot be easily hardened by sudden quenching because of large
amount of soft ferrite which is contains and all of which cannot be
retained in solution even on very quick cooling. The hardening capacity
of steel increases with carbon content.

Hardening methods

The most extensively used method is conventional hardening or
quenching in a single medium. The disadvantage of this method,
however, is that the cooling rate in the transformation range will be very
high. It will differ only slightly from the rate on the upper zone of supercooled
austenite of low stability and, therefore, cracks, distortion and
other defects may occur in this method.

Conventional Heat, Quench and Temper Process:

In this process, Austenite is transformed to Martensite as a result of rapid
quench from furnace to room temperature. Then, martensite is heated to a
temperature which gives the desired hardness. One serious drawback is
the possibility of distorting and cracking the metal as a result of severe
quenching required to form Martensite without transforming any of the
austenite to pearlite. During quenching process, the outer area is cooled
quicker than the center. Thinner parts are cooled faster than parts with
greater cross-sectional areas. What this means is that transformations of
the Austenite are proceeding at different rates. As the metal cools, it also
contracts and its microstructure occupies less volume. ]


Extreme variations in size of metal parts complicate the work of the heat
treater and should be avoided in the designing of metal parts. This means
there is a limit to the overall size of parts that can be subjected to such
thermal processing.

Conventional quenching and tempering process.
Other hardening method, which shall be briefly described, are generally
employed to avoid these defects ad to obtain the required properties.
The various hardening method are:
1. Quenching in two media.
2. Hardening with self tempering.
3. Stepped quenching or martempering.
4. Isotermal quenching or austempering.
34
1.Quenching in two media:
Articles hardening by this method are first quenched in water to a
temperature from 300°C to 400°C and then quickly transferred to a less
intensive quenching medium (for example oil or air) where they are held
until they are completely cooled. The purpose of the transfer to the
second quenching is to reduce internal stresses associated with the
austenite to martensite transformation. It is not advisable to quench first
in water and then in oil as this may lead to partial decomposition of the
austenite in its zone of the least stability (500C to 600°C) and to the
development of high residual stresses due to rapid cooling in martensite
transformation range.
Quenching in two media is widely employed in the heat treatment of
carbon steel tools (taps, dies, milling cutters etc.) of a shape unfavourable
as cracking and warping.
2.Hardening with self tempering:
Here the article is held in the quenching medium until it is completely
cooled but is withdrawn to retain a certain amount of heat in core which
accounts for the tempering (self tempering). Frequently, more heat is
retained in the core than is required for tempering and, when the
tempering temperature is reached, the article is reimmersed in the
quenching liquid.
This hardening is applied for chisels, sledge hammers, hand hammers,
centre punches, and other tools that require a high surface hardness in
conjunction with tough core.
3.Stepped quenching or martempering:
After heating the steel to a hardening temperature, it is quenched in the
medium having a temperature, from 150°C to 300°C. the article is held
until it reaches the temperature of medium and then its cooled further to
room temperature in air and sometimes in oil, the holding time in the
quenching bath should be sufficient to enable a uniform temperature to be
reached throughout the cross section but long enough to cause austenitic
decomposition. Austenite is transformed into martensite during the
subsequent period of cooling to room temperature.
35
This treatment will provide a structure of martensite and retained
austenite in the hardened steel. (the cooling is stopped at a point above
the martensite transformation region to allow sufficient time for the
center to cool to the same temperature as the surface. Then cooling is
continued through the martensite region, followed by the usual
tempering) [Figure 2.25 ] .
Figure 2.25 Martempering process.
Retained austenite there is a large volume expansion when
martensite forms from austenite. as the martensite plates form during
quenching, they surround and isolate small pools of austenite (Figure
2.26), which deform to accommodate the lower density martensite.
However, for the remaining pools of austenite to transform, the
surrounding martensite must deform. Because the strong martensite resist
the transformation, either the existing martensite cracks or the austenite
remains trapped in the structure as retained austenite.
36
Figure 2.26 Retained austenite (white) trapped between martensite
needles (black) ( 1000).
Retained austenite can be a serious problem. Martensite softens and
become more ductile during tempering. After tempering, the retained
austenite cools below the Ms and Mf temperatures and transforms to
martensite, since the surrounding tempered martensite can deform. But
now the steel contains more of the hard, brittle martensite. A second
tempering step may be needed to eliminate the martensite formed from
the retained austenite. Retained austenite is also more of a problem high
carbon steels.
The martensite stars and finish temperatures are reduced when the carbon
content increases (Figure2.27). High carbon steels must be refrigerated to
produce all martensite.
37
Figure 2.27 Increasing carbon reduces the Ms and Mf temperatures in
plain-carbon steels.
Residual stresses and cracking residual stresses are also
produced because of the volume change or because of cold working. A
stress relief anneal can be used to remove or minimize residual stresses
due to cold working. Stresses are also induced because of thermal
expansion and contraction. In steels, there is one more mechanism that
causes stress.
When steels are quenched, the surface of the quenched steel cools rapidly
and transforms to martensite. When the austenite in the center later
transforms, the hard surface is placed in tension, while the center is
compressed. If the residual stresses exceed the yield strength, quench
cracks form at the surface (Figure 2.28)
38
Figure 2.28 Formation of quench cracks caused by residual stresses
produced during quenching. The figure illustrates the development of
stresses as the austenite transforms to martensite during cooling.
Martempering has the following advantages over conventional
quenching:
1. less volume changes occur due to the presence of a large amount of
retained austenite and possibility of self tempering of the martensite.
2. less warping since the transformations occur simultaneously in all parts
of the article.
3. less danger of quenching cracks appearing in the articles.
On the other hand, the extremely low solubility of austenite in this range
from 500 to 600°C requires a cooling rate of 200 to 500°C per second in
this range to obtain supercooling. at the same time, cooling in hot media
is much slower than in water or oil at room temperature therefore,
austenite in carbon steel can be cooled through the zone from 600 to
500°C, without decomposition, only in thin articles (upto 5.8 mm I
thickness). Such articles are expediently hardened by this method. Alloy
steel articles hardened by this method, may be considerably thicker.
39
4. Isothermal quenching or austempering:
This is the second method that can be used to overcome the restrictions of
conventional quench and tempering. The quench is interrupted at a higher
temperature than for Martempering to allow the metal at the center of the
part to reach the same temperature as the surface. By maintaining that
temperature, both the center and the surface are allowed to transform to
Bainite and are then cooled to room temperature ( Figure 2.29).
Advantages of Austempering:
(1) Less distortion and cracking than martempering,
(2) No need for final tempering (less time consuming and more energy
efficient)
(3) Improvement of toughness (impact resistance is higher than the
conventional quench and tempering)
(4) Improved ductility
Limitations of Austempering:
Austempering can be applied to parts where the transformation to pearlite
can be avoided. This means that the section must be cooled fast enough to
avoid the formation of pearlite. Thin sections can be cooled faster than
the bulky sections. Most industrial applications of austempering have
been limited to sections less than 1/2 in. thick. The thickness can be
increased by the use of alloy steels, but then the time for completion of
transformation to bainite may become excessive.
40
Figure 2.29 Austempering process.
In Austempering process, the end product is 100% bainite. It is
accomplished by first heating the part to the properr austenitizing
temperature followed by cooling rapidly in a slat bath which is
maintained between 400 and 800 oF. The part is left in the bath until the
transformation to bainite is complete. The steel is caused to go directly
from austenite to bainite.
Quench rate In using the TTT diagram, we assume that we could
cool from the austenitizing temperature to the transformation temperature
instantly. because this does not occur in practice, undesired
microconstituents may form during the quenching process.
For example, pearlite may forms as steel cools past the nose of the curve,
particularly because the time of the nose is less than one second in plain
carbon steels.
The rate at which the steel cools during quenching depends on several
factors. First, the surface cools faster than the center of the part. In
addition, as the size of the part increases, the cooling rate at any location
is slower. Finally, the cooling rate depends on the temperature and heat
transfer characteristics of the quenching medium (Table 2.2 ).
41
Quenching in oil, for example, produces a lower H coefficient, or slower
cooling rate, than quenching in water and brine.
The H coefficient is equivalent to the heat transfer coefficient. Agitation
helps break the vapor blanket (e.g., when water is the quenching medium)
and improves overall heat transfer rate by bringing cooler liquid into
contact with the parts being quenched.
Sub-zero treatment
The resultant microstructure of a fully hardened steel should consist of
martensite. In practice, it is very difficult to have completely martensitic
structure by hardening treatment. Some amount of austenite is generally
present in the hardened steel. This austenite existing along with
martensite is referred to as retained austenite.
The presence of retained austenite greatly reduced mechanical properties
and such steels do not develop maximum hardness even after cooling at
rates higher than the critical cooling rate. The amount of retained
austenite depends largely on the chemical composition of steel. For plain
carbon steels, the amount of retained austenite increases with the rise in
carbon contents.
42
The problem of retained austenite is more complex in alloy steels. Most
of the alloying elements increase the content of retained austenite.
In hardened steels containing retained austenite, the strength can be
improved by process known as sub-zero treatment or cold treatment.
Retained austenite is converted into martensite by this treatment.
This conversion of retained austenite into martensite results in increased
hardness, wear resistance and dimensional stability of steel.
 The process consist of cooling steel to sub-zero temperature which
should be lower than Mf temperature of the steel. Mf temperature
for most steels lie between -30°C and -70°C.
During the process, considerable amount of internal stresses are
developed in the steel, and hence tempering is done immediately
after the treatment. This treatment also helps to temper martensite
which is formed by decomposition of retained austenite during subzero
treatment.
 Sub-zero treatment must be performed first after the hardening
treatment. Mechanical refrigeration units, dry ice, and some
liquefied gases such as liquid nitrogen can be used for cooling
steels to sub-zero temperature.
 This treatment is employed for : high carbon and high alloy steels
used for making tools, bearings, measuring gauges and components
requiring high impact and fatigue strength coupled with
dimensional stability-case hardened steels.
Example 2.4 Design of a Quench and Temper Treatment
A rotating shaft that delivers power from an electric motor is made from a
1050 steel. Its yield strength should be at least 145,000 psi, yet it should
also have at least 15% elongation in order to provide toughness. Design a
heat treatment to produce this part.

Solution:
We are not able to obtain this combination of properties by annealing or
normalizing . however a quench and temper heat treatment
produces Aa microstructure that can provide both strength and toughness.



shows that the yield strength exceeds 145.000 psi if the steel
is tempered below 460oC, whereas the elongation exceeds 15% if
tempering is done above 425oC.
The A3 temperature for the steel is 770oC. A possible heat treatment is:
1. Austenitize above the A3 temperature of 770oC for 1 h. An
appropriate temperature may be 770 + 55 = 825oC.
2. Quench rapidly to room temperature. Since the Mf is about 250oC,
martensite will form.
3. Temper by heating the steel to 440oC. Normally, 1 h will be
sufficient if the steel is not too thick.
4.Cool to room temperature.

ELLINGHAM DIAGRAMS

ELLINGHAM DIAGRAMS

Ellingham diags.(1944)for M-oxides & M-sulphides
are 70 yrs.old.
Later on, others had given diags. for
M-carbonates,-sulphates,-chlorides,-fluorides.

Now diags.areavailable for
M-carbides,-nitrides,-hydroxides,-sillicates,-phoisphatesetc.


THERMODYNAMICFEASIBILITYOFVARIOUSREACTIONSCANBEFOUNDOUTFROMFREEENERGYCALCULATIONS,
i.e.
1)which metal compound can be reduced,
2)by which reducing agent,
3)at what temperature,
4)Comparatively stability of various M-compounds of similar nature(e.g. various M-oxides, M-sulfides etc.)
5)Ratio of equilibrium partial pressure of gases involved for a given reactions,
e.g. for oxides: Pco/Pco2,PH2/PH2O,PO2etc.



ELLINGHAM DIAG. FOR OXIDES
Consider M-oxide system, 2Ms+ O2g= 2MOs
Equili.const. -…….. assuming M & MO in Std.state
(pure state),aM= 1,aMO=1,aO2=Po2
K=1/PO2
Now, by std.relation, ΔG°= -RTlnK
= -RTln1/PO2
= -
ΔGf°= RTlnPO2………….eq.1
Where,…………………………………………………………………………..
ΔGf°= Std. free energy change of the reaction involving only 1 mole
of O2gas reacting with M to form MO, hence called,
Std. free energy change for formation of MO per mole of O2.
PO2= Equili.oxygenpressure for M-oxide system
OR
Oxygen dissociation pressure for M-oxide.



Since, ΔGf°= RTlnPO2--------eq.1 above,
for a metal oxide system, ΔGf°varies with Po2and T.
---------------------------------------------------------------------------------------
For the reaction, 2M +O2 = 2MO
(1)If MO has very low Po2compare to Po2of external atmos.,
then MO is more stable or difficult to reduce and ΔGf°= -ve, for above reaction.

(2)If MO has high Po2compare to Po2of external atmos., then MO is less stable or easy to reduce and ΔGf°= +ve, for above reaction.
---------------------------------------------------------------------------------------
Let us consider St.lineeq. y = mx+c……….…..eq.2
Also,asper std.relation, ΔGf°= ΔHf°–TΔSf°…...eq.3
Comparing eq.2 & 3 above,
slope=m= -ΔSf°….also called, std.entropyof formation of oxide,
Intercept=c = ΔHf°also called, std.heatof formation of oxide.


IMP.FEATURESOFDIAG.FORM-MO SYSTEM

(1)..(a)In all cases: 2Ms+O2g=2MOs
(gas vol. in mole)...1O
Since gas phase has much higher entropy than condensed phase,
in above case, entropy decreases & hence entropy change,ΔSf°=-ve.
(when, ΔSf°=-ve,thenΔGf°= +ve& slope of the line will be positive,Fig1).
------------------------------------------------------------------------------------------
(b)In case of: 2Cs+O2g=2COg
(gas vol.inmole)….1 2
i.e. entropy increases & entropy change, ΔSf°= +ve.
(when, ΔSf°=+ve,thenΔGf°=-ve& slope of the line will be negetive,
----------------------------------------------------------------------------------Fig 2).
(c) In case of: Cs+O2g = CO2g
(gas vol. in mole).. 1 1
(entropy does not change, ΔSf°= 0,ΔGf°= ΔHf°, slope = 0,&
line is horizontal ,Fig 2).

                         ASSEENINELLINGHAMDIAG.(FIG.3)

(2)Kinks:
The lines are straight lines with kinks, because of phasechangesin either metal or it’s oxides due melting, boiling, sublimation or transition point.
________________________________________________________
Due to phase change at kink, ΔSf°will change and hence slope of the line changes.
_________________________________________________________
Change of slope is much sharper for boiling & sublimation temps.thanfor melting temp. because, ΔSf°at the melting pt. is much less than at boiling or sublimation pt.
___________________________________________________


(3)Reduction of ‘MO’ by C:

As shown in fig.2,in case of,
2Cs+ O2g=2COg…….as T increases, ΔSf°& ΔGf°
(This is not true in almost all other cases).
And this makes Carbon, a useful reducing agent.
--------------------------------------------------------------------------------
The temp. at which M-MO & C-CO line intersects gives
equili.temp. of reduction of MO by C at 1 atm. Pressure.
--------------------------------------------------------------------------------
Thus from Ellingham diag. temp.ofreduction of MO by C is,
for MnO--->1400 °C & for Al2O3--->2000 °C
------------------------------------------------------------------------------------------

(4)STABILITYOFCO & CO2

As seen in Fig.2,the lines C-CO & C-CO2cross each other at 723 °C,
Below 723 °C, CO2gis more stable than COg
and
above 723 °C, COgis more stable than CO2g
Hence below 723 °C, MO+C M+CO2
and above 723 °C, MO+C M+CO
e.g.
2PbOs+Cs=2Pbs+CO2g…………..at 100◦C
ZnSs+Cs=Zng+COg………………at1200◦C


(5)Reduction of ‘MO’ by reducing agent,otherthan carbon:

Itis not necessary that two curves of M-MO should always intersect each-other for reduction, as discussed for reduction by carbone.g. reduction of Cr2O3by Al or Pbat 1200 °C
-------------------------------------------------------------------------------------------
Each curve is for 1mole of O2,
hence distance between two curves at any temp. gives ΔGf
for the reduction of oxide.

METHODS OF REFINING

METHODSOFREFINING:

(It depends on whether commercial or high purity is wanted).
Chemical methods:
1)Fire refining2)Refining via volatile compound
(In this chemical reactions are involved).
---------------------------------------------------------------------------------
Electro-chemical method:
3)Electrolysis(Electro refining)
(In this electrochemical reactions are involved).
---------------------------------------------------------------------------------
Physical methods:
4)Liquation5)Selective distillation of impurities
6)Zone refining.
(In this no chemical or electrochemical reactions are
------------------------------------------------------------------involved).

ELECTRO-METALLURGY

  ELECTRO-METALLURGY

All metallurgical processes using electricity& electric effect.
It may be carried out at room or high temperature.

Classification:

(1) Electrothermic: Current is used for heating only.
e.g. E A F or I F steelmaking.

(2) Electrolytic:Currentis used for electrolysis.
-Electrowinning:Ext.ofmetal from aq.soln.(leach liquor) or fused salt.
-Electrorefining: Refining of metal(from impure anodes).


Electrowinningis commercially used for Al,Na,Mg,Cr,Cu,Nietc.
Merit-high purity metal.
Demerit-costly due to high cost of electricity

HYDRO-METALLURGY GTU

HYDRO-METALLURGY

It is used for treating low grade ore using water or aqueous
solution(dil.acids/bases/salts)as leaching agent. The leaching
agent should dissolve only ore-minerals & not gangue minerals. Also,itshould be cheap & readily obtainable.
Main steps are:---------------------------------------------------------------

1)Leachingor digestion: heap/ percolation/ pressure/ bacterial.

2)Separation: sedimentation & decantation/ filtration.

3)Purification: precipitation/ ion exchange/ solvent extraction.

4)Reduction: pyro-metallurgy(gaseous reduction of aq.soln.)
or electro-metallurgy(electrowinning).

Thus, hydro-metallurgy is a process of beneficiation as well as extraction.

PYROMETALLURGY GTU

ION IMPLANTATION

                 ION  implantation

Ion implantation is a materials engineering process by which ions of
a material are accelerated in an electrical field and impacted into a
solid. This process is used to change the physical, chemical, or
electrical properties of the solid. Ion implantation is used in
semiconductor device fabrication and in metal finishing, as well as
various applications in materials science research. The ions alter the
elemental composition of the target (if the ions differ in composition
from the target), stopping in the target and staying there. They also
cause many chemical and physical changes in the target by transferring
their energy and momentum to the electrons and atomic nuclei of the
target material. This causes a structural change, in that the crystal
structure of the target can be damaged or even destroyed by the
energetic collision cascades. Because the ions have masses comparable
to those of the target atoms, they knock the target atoms out of place
more than electron beams do. If the ion energy is sufficiently high
(usually tens of MeV) to overcome the coulomb barrier, there can even
be a small amount of nuclear transmutation.



Contents
1 General principle
2 Application in semiconductor device fabrication
2.1 Doping
2.2 Silicon on insulator
2.3 Mesotaxy
3 Application in metal finishing
3.1 Tool steel toughening
3.2 Surface finishing
4 Other applications
4.1 Ion beam mixing
5 Problems with ion implantation
5.1 Crystallographic damage
5.2 Damage recovery
5.3 Amorphization
5.4 Sputtering
5.5 Ion channelling
6 Hazardous materials
6.1 High voltage safety
7 See also
8 References
9 External links

General principle

Ion implantation equipment typically consists of an ion source, where ions
of the desired element are produced, an accelerator, where the ions are
electrostatically accelerated to a high energy, and a target chamber, where
the ions impinge on a target, which is the material to be implanted. Thus
ion implantation is a special case of particle radiation. Each ion is typically
a single atom or molecule, and thus the actual amount of material implanted
in the target is the integral over time of the ion current. This amount is
called the dose. The currents supplied by implanters are typically small
(microamperes), and thus the dose which can be implanted in a reasonable
amount of time is small. Therefore, ion implantation finds application in
cases where the amount of chemical change required is small.
Typical ion energies are in the range of 10 to 500 keV (1,600 to 80,000 aJ).
Energies in the range 1 to 10 keV (160 to 1,600 aJ) can be used, but result
in a penetration of only a few nanometers or less. Energies lower than this
result in very little damage to the target, and fall under the designation ion
beam deposition. Higher energies can also be used: accelerators capable of 5 MeV (800,000 aJ) are common.
However, there is often great structural damage to the target, and because the depth distribution is broad (Bragg
peak), the net composition change at any point in the target will be small.
The energy of the ions, as well as the ion species and the composition of the target determine the depth of
penetration of the ions in the solid: A monoenergetic ion beam will generally have a broad depth distribution. The
average penetration depth is called the range of the ions. Under typical circumstances ion ranges will be between
10 nanometers and 1 micrometer. Thus, ion implantation is especially useful in cases where the chemical or
structural change is desired to be near the surface of the target. Ions gradually lose their energy as they travel
through the solid, both from occasional collisions with target atoms (which cause abrupt energy transfers) and from
a mild drag from overlap of electron orbitals, which is a continuous process. The loss of ion energy in the target is
called stopping and can be simulated with the binary collision approximation method.
Accelerator systems for ion implantation are generally classified into medium current (ion beam currents between
10 μA and ~2 mA), high current (ion beam currents up to ~30 mA), high energy (ion energies above 200 keV and
up to 10 MeV), and very high dose (efficient implant of dose greater than 1016 ions/cm2).
All varieties of ion implantation beamline designs contain certain general groups of functional components (see
image). The first major segment of an ion beamline includes a device known as an ion source to generate the ion
species. The source is closely coupled to biased electrodes for extraction of the ions into the beamline and most
often to some means of selecting a particular ion species for transport into the main accelerator section. The "mass"
selection is often accompanied by passage of the extracted ion beam through a magnetic field region with an exit
path restricted by blocking apertures, or "slits", that allow only ions with a specific value of the product of mass
and velocity/charge to continue down the beamline. If the target surface is larger than the ion beam diameter and a
uniform distribution of implanted dose is desired over the target surface, then some combination of beam scanning
and wafer motion is used. Finally, the implanted surface is coupled with some method for collecting the
accumulated charge of the implanted ions so that the delivered dose can be measured in a continuous fashion and
the implant process stopped at the desired dose level.[1]
Application in semiconductor device fabrication


Doping

•The introduction of dopants in a semiconductor is the most common application of ion implantation. • Dopant
ions such as boron, phosphorus or arsenic are generally created from a gas source, so that the purity of the source
can be very high. •These gases tend to be very hazardous. When implanted in a semiconductor, each dopant atom
can create a charge carrier in the semiconductor after annealing. A hole can be created for a ptype
dopant, and an
electron for an ntype
dopant. This modifies the conductivity of the semiconductor in its vicinity. The technique is
used, for example, for adjusting the threshold of a MOSFET.
Ion implantation was developed as a method of producing the pn
junction of photovoltaic devices in the late
1970s and early 1980s,[2] along with the use of pulsedelectron
beam for rapid annealing,[3] although it has not to
date been used for commercial production.


Silicon on insulator
One prominent method for preparing silicon on insulator (SOI) substrates from conventional silicon substrates is
the SIMOX (separation by implantation of oxygen) process, wherein a buried high dose oxygen implant is
converted to silicon oxide by a high temperature annealing process.
Mesotaxy
Mesotaxy is the term for the growth of a crystallographically matching phase underneath the surface of the host
crystal (compare to epitaxy, which is the growth of the matching phase on the surface of a substrate). In this
process, ions are implanted at a high enough energy and dose into a material to create a layer of a second phase,
and the temperature is controlled so that the crystal structure of the target is not destroyed. The crystal orientation
of the layer can be engineered to match that of the target, even though the exact crystal structure and lattice
constant may be very different. For example, after the implantation of nickel ions into a silicon wafer, a layer of
nickel silicide can be grown in which the crystal orientation of the silicide matches that of the silicon.


Application in metal finishing
Tool steel toughening
Nitrogen or other ions can be implanted into a tool steel target (drill bits, for example). The structural change
caused by the implantation produces a surface compression in the steel, which prevents crack propagation and thus
makes the material more resistant to fracture. The chemical change can also make the tool more resistant to
corrosion.


Surface finishing
In some applications, for example prosthetic devices such as artificial joints, it is desired to have surfaces very
resistant to both chemical corrosion and wear due to friction. Ion implantation is used in such cases to engineer the
surfaces of such devices for more reliable performance. As in the case of tool steels, the surface modification
caused by ion implantation includes both a surface compression which prevents crack propagation and an alloying
of the surface to make it more chemically resistant to corrosion.
Other applications
Ion beam mixing

GTU project

                                   Gujarat Technological University
                         Project Monitoring and Mentoring System (PMMS)
USER MANUAL FOR INTERNAL GUIDE
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 2 | 56
Table of Contents
1. Internal Guide Dashboard ............................................................................................................. 3
2. Change Password .......................................................................................................................... 5
3. Team Approval Requests .............................................................................................................. 6
4. Request for Add Team Member ................................................................................................... 8
5. Request to Remove Students ........................................................................................................ 9
6. Request to Remove Students Report .......................................................................................... 10
7. Request to Change Team Lead ................................................................................................... 11
8. List of Request to Change Team Leader ..................................................................................... 13
9. List of Projects Approval for Mentorship .................................................................................... 15
10. Student Activity Analysis by Authority .................................................................................... 16
11. Periodic Progress Report (PPR) ............................................................................................... 18
12. Design Engineering Canvas ..................................................................................................... 23
13. PSAR ........................................................................................................................................ 28
14. Plagiarism Report .................................................................................................................... 34
15. Project Report ......................................................................................................................... 38
16. Completion Certificate ............................................................................................................ 42
17. Internal Guide Dashboard ....................................................................................................... 44
18. Active Projects......................................................................................................................... 46
19. Internal Guide Dashboard ....................................................................................................... 48
20. List of Business Model Canvas (BMC) ..................................................................................... 50
21. PDE Reports............................................................................................................................. 53
22. Completion Certificate ............................................................................................................ 56
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 3 | 56
1. Internal Guide Dashboard
1. Go to Internal Guide Dashboard tab from My Account menu as shown in below screen.
A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 4 | 56
2. Dashboard will be displayed.
B
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 5 | 56
2. Change Password
1. Go to Change Password tab from My Account menu as shown in below screen.
2. Fill the required details as shown in figure below
3. Click on Change Password Button
A B C
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 6 | 56
3. Team Approval Requests
1. Go to Team Approval Requests tab from Internal Guide menu as shown in below screen.
2. Click on Search Button
3. Click on View Details link
A B C
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 7 | 56
4. Approve/Reject team as per your desired
D
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 8 | 56
4. Request for Add Team Member
1. Go to Request for Add Team Member tab from Internal Guide menu as shown in below screen.
2. Approve/Reject request for Add Team Member submitted by Team Leader of the team under your guidance
A B
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 9 | 56
5. Request to Remove Students
1. Go to Request to Remove Students tab from Internal Guide menu as shown in below screen.
2. Select Project Name
3. Approve/Reject Request to Remove Students submitted by Team Leader of the team under your guidance
A B C
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 10 | 56
6. Request to Remove Students Report
1. Go to Request to Remove Students Report tab from Internal Guide menu as shown in below screen.
2. Select Project Name
3. List will be displayed with status (i.e. Pending or Approved)
B A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 11 | 56
7. Request to Change Team Lead
1. Go to Request for Request to Change Team Lead tab from Internal Guide menu as shown in below screen.
2. Select Project Name Click on Search Button
3. Approve/Reject the list of all Requests to Change Team Lead
A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 12 | 56
C B
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 13 | 56
8. List of Request to Change Team Leader
1. Go to List of Request to Change Team Leader tab from Internal Guide menu as shown in below screen.
2. Select Project Name
3. List of Request to Change Team Leader will be displayed with its status
A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 14 | 56
B C
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 15 | 56
9. List of Projects Approval for Mentorship
1. Go to List of Projects Approval for Mentorship tab from Internal Guide menu as shown in below screen.
2. Click on Search Button
A B
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 16 | 56
10. Student Activity Analysis by Authority
1. Go to Student Activity Analysis by Authority tab from Internal Guide menu as shown in below screen.
2. Enter student’s enrollment number
3. Click Search Button.
4. Students activity details will be displayed
A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 17 | 56
B C D
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 18 | 56
11. Periodic Progress Report (PPR)
1. Go to Periodic Progress Report (PPR) tab from Internal Guide menu as shown in below screen.
A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 19 | 56
2. Enter student’s enrollment number
3. Click Search Button.
4. Click on View Link
B C D
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 20 | 56
5. All students submitted/commented ppr list will be displayed
6. Click on Review/Comment Link to review/comment your students activity
F E
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 21 | 56
7. Fill desired Comments on Activity
8. Click SUBMIT COMENTS/REVIEW Button to respectively comment/review the desired activity
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 22 | 56
G H
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 23 | 56
12. Design Engineering Canvas
1. Go to Design Engineering Canvas tab from Internal Guide menu as shown in below screen.
A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 24 | 56
2. Read all the instructions and Click on PROCEED Button
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 25 | 56
3. Click Search Button.
4. Click on Review/Comment Link to review/comment your students activity
C B
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 26 | 56
5. Fill desired Comments on Activity
6. Click SUBMIT COMENTS/REVIEW Button to respectively comment/review the desired activity
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 27 | 56
D E
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 28 | 56
13. PSAR
1. Go to Request for PSAR tab from Internal Guide menu as shown in below screen.
2. Read all the instructions and Click on PROCEED Button
. A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 29 | 56
B
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 30 | 56
3. Enter desired Enrollment number and Click on Search Button
D C
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 31 | 56
4. Click on Review/Comment Link to review/comment your students activity
5. Click on View details link
E
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 32 | 56
6. Fill desired Comments on Activity
7. Click SUBMIT COMENTS/REVIEW Button to respectively comment/review the desired activity
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 33 | 56
E F
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 34 | 56
14. Plagiarism Report
1. Go to Plagiarism Report tab from Internal Guide menu as shown in below screen.
2. Read all the instructions and Click on PROCEED Button
A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 35 | 56
B
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 36 | 56
3. Click Search Button
4. Click on Review/Comment Link to review/comment your students activity
C D
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 37 | 56
5. Fill desired Comments on Activity
6. Click SUBMIT COMENTS/REVIEW Button to respectively comment/review the desired activity
E F
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 38 | 56
15. Project Report
1. Go to Project Report tab from Internal Guide menu as shown in below screen.
A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 39 | 56
2. Read all the instructions and Click on PROCEED Button
B
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 40 | 56
3. Click on Search Button
4. Click on Review/Comment Link to review/comment your students activity
C D
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 41 | 56
5. Fill desired Comments on Activity
6. Click SUBMIT COMENTS/REVIEW Button to respectively comment/review the desired activity
E F
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 42 | 56
16. Completion Certificate
1. Go to Completion Certificate tab from Internal Guide menu as shown in below screen.
A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 43 | 56
2. Click Search button
3. Download Certificate of each and every student under you whose all activities have been reviewed by you.
C B
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 44 | 56
17. Internal Guide Dashboard
1. Go to Internal Guide Dashboard tab from Internal Guide menu as shown in below screen.
A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 45 | 56
2. Dashboard will be displayed
B
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 46 | 56
18. Active Projects
1. Go to Active Projects tab from Internal Guide menu as shown in below screen and all active projects list that are currently under your guidance will be listed.
2. Click on Search Button
3. Click on View details link
A C B
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 47 | 56
4. You can View Team Profile of the students team under your guidance
D
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 48 | 56
BE 8 semester 19. Internal Guide Dashboard
1. Go to Internal Guide Dashboard tab from My Account menu as shown in below screen.
A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 49 | 56
2. Dashboard will be displayed
B
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 50 | 56
20. List of Business Model Canvas (BMC)
1. Go to List of Business Model Canvas (BMC) tab from Internal Guide menu as shown in below screen.
2. Click on Search Button
3. Click on Review/Comment Link to review/comment your students activity
A
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 51 | 56
4. Comment on respective Activity
5. Click SUBMIT COMENTS/REVIEW Button to respectively comment/review the desired activity B C
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 52 | 56
D E
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 53 | 56
21. PDE Reports
1. Go to List of PDE Reports tab from Internal Guide menu as shown in below screen.
2. Click on Search Button
3. Click on Review/Comment Link to review/comment your students activity
A B C
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 54 | 56
4. Comment on respective Activity
5. Click SUBMIT COMENTS/REVIEW Button to respectively comment/review the desired activity
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 55 | 56
D E
GTU Innovation Council
PMMS – User Manual for Internal Guide Page 56 | 56
22. Completion Certificate

    

FUELS, FURNACES, REFRACTORIES AND PYROMETRY 2152104

                   GUJARAT TECHNOLOGICAL UNIVERSITY
METALLURGY ENGINEERING (21)
           FUELS, FURNACES, REFRACTORIES AND PYROMETRY
SUBJECT CODE: 2152104
B.E. 5th SEMESTER

Type of course: Engineering Science
Prerequisite: Knowledge of Elements of Metallurgy and basic science skills
Rationale: The Fuels, Furnaces, Refractories and Pyrometry course is to prepare students for careers in metallurgy engineering where knowledge of Fuels, Furnaces, Refractories and Pyrometry can be applied to the advancement of technology. All important metallurgical operations like extraction of metals, melting, heat treatment etc. are carried out in various metallurgical furnaces. Fuels are basic requirements of furnaces and play a major role in quality and cost of any metallurgical product. Optimum utilization and quality control of fuel is must in metallurgical operations. Refractories are very important material for construction of furnaces which help in the efficient utilization of heat in furnace. Knowledge of Temperature Measurement and Control is must for functioning of furnaces. Thus Fuels, Furnaces, Refractories and Pyrometry course will enable students to solve metallurgical problems upon graduation while at the same time, provide a firm foundation for the pursuit of graduate studies in metallurgy engineering.

SYLLABUS


Content:
1 Temperature Measurement and Control: Basic concept of temperature measurement and control. Thermocouples: Principal, calibration, types and advantages. Optical and Radiation pyrometers: principle, construction, working and advantages.

 2 Fuels - General : Definition, Comparative study of solid, liquid and gaseous fuels. Constitution, classification and grading of coal. Testing of fuels like: Grindability, Caking properties, calorific value, Proximate and ultimate analysis, Flash and Fire point, viscosity etc. Non-conventional Energy Resources like Nuclear fuel, Solar, Wind, Geo-thermal, Bio-mass, Hydrogen etc.

 3 Fuels - Manufacturing: Carbonization of coal: Coke making and by-products. Producer gas, Water gas, Natural gas, LPG, Blast furnace gas, Coke oven gas, LD gas. Storage of fuels. Combustion of fuels and problems based on air supplied, excess air and products of combustion.

 4 Furnaces: Definition and Classification of Furnaces, Batch furnaces, Continuous furnaces. Construction and working of furnaces like Cupola, Induction furnace, Arc furnace, Resistance furnace, Pit furnace, Rotary furnace, Muffle furnace etc.


Reference Books:
1. Elements of Fuels, Furnaces and Refractories, O. P. Gupta, Khanna publication.
2. Fuels, Furnaces and Refractories, J. D. Gilchrist
3. Fuels, Furnaces, Refractories and Pyrometry,-A.V.K. Suryanarayana, B. S. Publication
4. Industrial Furnaces - Vol. I & II, W. Trinks and M. H. Mawhiney, Wiley
5. Refractories, F.H.Norton, McGraw-Hill
6. Refractories, M. L. Mishra
Course Outcome:
After learning the course the students should be able to:
1. Explain various temperature measurement and control devices.
2. Compare different types of fuels and describe their testing methods.
3. Explain the coke making process and its by-products recovery.
4. Explain the use of different Non-conventional energy Resources for metallurgical applications.
5. Explain different aspects of Combustion process of fuels and Solve problems based on this.
6. Classify and explain Construction and working of different furnaces.
7. Analyze causes of Heat losses in furnaces and suggest methods of minimization it and Waste heat recovery.
8. Explain various Properties, manufacturing and testing of refractories.
9. Select the relevant refractory material for the metallurgical operations.
10. Demonstrate the ability to use the core concepts of engineering application in Fuels, Furnaces, Refractories and Pyrometry.
11. Demonstrate the ability to select the proper type of furnace with relevant refractory material, use appropriate Fuel and temperature measurement device to obtain qualitative solutions of given metallurgical operation.
List of Experiments:
1. To study working of thermocouple and calibrate a given thermocouple.
2. To measure the temperature of a red hot object using Optical /Radiation Pyrometer.
3. To study and identify different types of fuels.
4. To carry out proximate and ultimate analysis of a given coal sample.
5. To determine calorific value of a solid and liquid fuel.
6. To determine Flash and fire point of a fuel oil.
7. To determine the viscosity (in ‘Redwood seconds’) of a liquid hydrocarbon and effect of temperature on the viscosity. Evolution of heat and flame temperature. Available heat. Natural, forced, induced and balanced draft. Chimney height, Heat losses in furnaces and minimization. Waste heat recovery. 5 Refractories: Definition, Classification, Properties and testing of refractories. General Production method of refractories, Selection of refractories for metallurgical applications, Special types of refractories. 10 17 Total 60 100
8. To study the different types of furnaces.
9. To study the properties and applications of different refractories.
10. To determine permeability number of a refractory sample.
11. To study pyrometric cone equivalent (PCE) test of a refractory sample.
Design based Problems (DP)/Open Ended Problem:
1. Chart of different temperature measurement and control devices.
2. Problems based on Combustion of fuels.
3. Chart of different Furnaces.
4. Chart of flow-sheet of refractory production.
5. Collection and Study of various types of fuel, refractories and temperature measurement devices.
6. Group discussion and Presentations on recent fuel scenario and advancement in furnace technology.
7. Any other problem decided by faculty based on syllabus.
Major Equipment:
1. Thermocouples
2. Milivoltmeter
3. Thermometer
4. Optical / Radiation Pyrometer
5. Muffle furnaces
6. Dessicators
7. Kjeldahl’s flask
8. Digital electronic balance
9. Bomb-Calorimeter
10. Pensky-Martens Apparatus
11. Redwood Apparatus No. 1 and 2
12. Permeability meter
List of Open Source Software/learning website:
1. http://nptel.iitm.ac.in/
2. www.ocw.mit.edu
ACTIVE LEARNING ASSIGNMENTS: Preparation of power-point slides, which include videos, animations, pictures, graphics for better understanding theory and practical work – The faculty will allocate chapters/ parts of chapters to groups of students so that the entire syllabus to be covered. The power-point slides should be put up on the web-site of the College/ Institute, along with the names of the students of the group, the name of the faculty, Department and College on the first slide. The best three works should submit to GTU.