Heat Treatment of Medium Carbon Steel
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Transcript of Heat Treatment of Medium Carbon Steel
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Heat Treatment of medium carbon steel
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SIDDAGANGA INSTITUTE OF TECHNOLOGY
(An autonomous institution under Visvesvaraya technological University, Belgaum)
Tumkur - 572 103, Karnataka, India
Project synopsis presented in partial fulfilment of the requirements for the 5th Semester
of
BACHELOR OF ENGINEERING
IN
MECHANICAL ENGINEERING
HEAT TREATMENT OF MEDIUM CARBON STEEL
Ajaya kumar v (1SI10ME132)
Jabeeulla (1SI11ME408)
Madhusudana JM (1SI11ME411)
Manjunatha p (1SI11ME412)
Sri. M SHIVASHANKERM.E Dr. U S MALLIKARJUN
M.E, Ph.D
Associate Professor Prof. & Head
Department of Mechanical Engineering Department of Mechanical Engineering
S I T, Tumkur S I T, Tumkur
Submitted by
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What is Heat Treating ?
Arvind Thekdi - E3M, Inc.Sales
Holding
(soak)
Time
Temperature
Controlled Heating And Cooling of Metal to Change Its Properties andPerformance.
Through:
Change in Microstructure
Change in Chemistry or Composition
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EXPERIMENTAL PROCEDURE:
The experimental procedure for the project work can belisted as :
Specimen preparation
Heat treatment
Hardness measurement
Mechanical property study
Microstructure study
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EXPERIMENTAL PROCEDUREThe experimental procedure for theproject work can be listed as :
Specimen preparation
Heat treatment
Hardness measurement
Mechanical property study
Microstructure study
Equipments
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Composition 0f C-60 steel
C 0.57~0.65
Si 0.17~0.37
Mn 0.50~0.80
S 0.035
P 0.035
Cr 0.25
Ni 0.25
Cu 0.25
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SPECIMEN PREPARATION
The first and foremost job for the experiment is the
specimen preparation.
The specimen size should be compatible to the machine
specifications:
We got the sample from medium carbon steel trader. The
sample that we got was Medium carbon steel. AISI8620:It is
one of the American standard specifications of the mild
steel having the pearlitic matrix (up to40%) with relatively less
amount of ferrite
(30-40%). And so it has high hardness with moderate ductility
and high strength as specified below.
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STUDY OF MECHANICAL PROPERTIES:
in a high hardness number. The hardness
value thus obtained was converted into C
As the objective of the project is to compare
the mechanical properties of various
heat treated C-60 specimens, now the
specimens were sent to hardness testing
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HEAT TREATMENT
medium Carbon Steel are primarily heat
treated to create matrix microstructures
and associated mechanical properties not
readily obtained in the as-cast condition.
As-cast matrix microstructures usually
consist of ferrite or pearlite
objective of the project is to carry out theheat treatment of medium carbon steel
and then to compare the mechanical
properties. There are various types of
quenching processes we had adopted.
The specimen was heated to a
temperature of 840 deg Celsius At 840 degCelsius the specimen was held for 40 min
The objective of keeping the specimen at
840 deg Celsius for 40 min is to
homogenize the specimen
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HEAT TREATMENT
medium Carbon Steel are primarily heat treated to creatematrix microstructures and associated mechanical properties
not readily obtained in the as-cast condition. As-cast matrix
microstructures usually consist of ferrite or pearlite
objective of the project is to carry out the heat treatment of
medium carbon steel and then to compare the mechanical
properties. There are various types of quenching processes
we had adopted.
The specimen was heated to a temperature of 840 deg Celsius
At 840 deg Celsius the specimen was held for 40 min
The objective of keeping the specimen at 840 deg Celsius for
40 min is to homogenize the specimen.
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The temperature 840 deg Celsius lies above Ac1
temperature. So that the specimen at that temperature gets
sufficient time to get properly homogenized .
The specimen was taken out of the furnace when
the furnace temperature had already reached the840 deg temperature
At the very beginning the specimen was heated to
the temperature of 840 deg
Celsius.Then the furnace was switched off and the
specimen was taken out and quenching in different
medium
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Heat treatment furnaceFurnaces
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Different Quenching Medium
water
Hot water
ice oil
Oil with additive
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QUENCHING:
The specimen was heated to the temp of around 840 degCelsius and were
allowed to homogenize at that temp for 40 min.
b) An quenching medium was maintained at a constanttemperature in which the specimen had to be put.
After 40 min the specimen was taken out of the furnace anddirectly quenched in the different medium like water ,ice ,hotwater .oil ,oil with additives.
Note down the decreasing temperature in time 1sec,10sec,and100sec
d) After quenching specimen was taken out of the bath andcleaned properly
Now the specimen attains the liquid bath temp within fewminutes. But the rate
of cooling is very fast because the liquid doesnt release heatreadily.
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water
Hot water
ice
Oil
Diff t Q hi M di &
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18
Different Quenching Medium &
Geometry Effect of quenching medium:
Medium
Hot water
oil
Water
Oil with additive
ice
Severity of Quench
low
moderate
High
Moderate
medium
Hardness
low
moderate
High
Moderate
medium
Effect of geometry:
When surface-to-volume ratio increases:
--cooling rate increases
--hardness increases
Position
center
surface
Cooling rate
medium
high
Hardness
high
high
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QUENCHING for DIFFERENT MEDIA
TEMPRATURE W\S TIME
SL.NO QUENCHINGMEDIUM
TEMPARATURE TIME
1. WATER 186 1
70 10
47 100
2. HOT WATER 624 1
320 10
68 100
3. ICE 525 1
484 10120 100
4. OIL 190 1
136 10
50 100
5. OIL WITH 247 1
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-10 0 10 20 30 40 50 60 70 80 90 100 110
0
100
200
300
400
500
600
700
Temperature
indegreeC
Time in Sec
AQuenching Medium Hot water
HARDNESS TESTING
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Rockwell hardness machine
HARDNESS TESTING
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STEPS FOR HARDENING
Check carbon content of steel it must be
above 60% to harden
Heat furnace to the upper crictical Temp 800
to 1200 degree c
Check treating & carbon graph to determine
this value,
Allow steel time to completely heat trough
out.
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HARDNESS TESTING
The heat treated specimens hardness were measured by means of
Rockwell hardness tester. The procedure adopted can be listed as follows:
First the diamond indenter was inserted in the machine; the load is
adjusted to1500kg.
Now the major load applied and the depth of indentation is automatically
recorded on a dial gage in terms of arbitrary hardness numbers. The dial
contains 100 divisions. Each division corresponds to a penetration of .002
mm. The dial is reversed so that a high hardness, which results in small
penetration, results in a high hardness number. The hardness value thus
obtained was converted into C
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ROCKWELL HARD NESS TEST
SL.N
O
MATERIAL LOAD
IN
KgS
DIA. OF
DIAMOND
INDENTER
TIM
E IN
SEC.
QUENCHING
MEDIUM
HARDNESS
NUMBER
MEAN
1 2 3
1.
C-60
STEEL
1500 5 20
WATER 71 74 73 73
2 HOT WATER 65 67 70 67
3 ICE 50 52 56 53
4 OIL WITHADDITIVES
48 47 40 45
5 OIL 39 34 39 37
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TABULATION FOR HARDNESS TESTING
0
10
20
30
40
50
60
70
80
QUENCHING MEDIUM
WATER
H0T WATER
ICE
OIL WITH ADDITIES
OIL
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CONCLUSION:
From the various results obtained during the project work it
can be concluded that the mechanical Properties VaryDepending Upon The Various Heat treatment processes and
quenching medium.
Hence depending upon the properties and applications
required we should go for a suitable heat treatmentprocesses. When ductility is the only criteria
experiments however it is simply the hardness of the
medium carbon steel that is desired than we should go for
low temperature 40 min or so.
However if strength is also desired along with hardness, this
should not be done.
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Heat Treatments
a) Annealing
28
b) Quenching
c)
c) Tempered
Martensite
Adapted from Fig. 10.22, Callister 7e.
time (s)10 10
310
510
-1
400
600
800
T(C)
Austenite (stable)
200
P
B
TE
A
A
M + A
M + A
0%
50%
90%a)b)
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THANK YOU