heat treatment of medium carbon steel

7/30/2019 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

heat treatment of medium carbon steel

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