This experiment investigates the heat treatment of steel through examining microstructures, hardness testing, and relating microstructure to hardness. Six steel specimens are subjected to different heat treatments - including austenitizing, quenching, and tempering - and their microstructures and hardness measured. The goals are to understand how heat treating alters steel microstructure and properties like hardness, and examine sources of error and relationships between different hardness tests.
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Conventional heat treatment of low carbon steelAyush Chaurasia
Heat treatment of Low Carbon Steel via heat treatment processes of annealing, quenching and normalising and observing the structural changes affecting the hardness property of material.
Effect of cryogenic treatment on tool steel (aisi ¬d2)eSAT Journals
Abstract
In present scenario modernization of machine tools is on prime consideration that is an optimization of desired properties in machine tool parts means alternation of properties for that previously we employed heat treatment of steel, thus we have some improved properties but does not achieved correct solution for the problem. In modern age a new technology is comes on the front line, recognize by Acronyms C.T.P. or Cryogenic treatment of steel which has been done in cooling Atmosphere below Atmospheric tem. About – 1960C or- 3100F. During this temp. Range conversion of Austenite to marten site takes place. Thus we have got increased some desirable properties like reduced wear & Tear. Increased Hardness Micro- structure improved, Stress relieving properties also improved. In this paper tool Steel AISI- D2 is used for cryogenic treatment & study is performed regarding Micro- structure and Hardness, after Cryogenic treatment comparison is also made with un-treated test specimen.
Keywords:-AISI- D2, Cryogenic Treatment, Phase Transformation, Hardness, Micro- Structure
EFFECT OF SCANDIUM ON THE SOFTENING BEHAVIOUR OF DIFFERENT DEGREE OF COLD ROL...msejjournal
The softening behavior of different cold rolled Al-6Mg alloys containing scandium 0.2 wt% and 0.6 wt% have been investigated by means of microscopy, hardness and electrical conductivity measurements. It is found that the scandium added alloys attend the higher hardness at every state of cold rolling at higher
annealed temperature due to the precipitation of scandium aluminides. Electrical resistivity of the scandium added alloys show higher than base alloy due to grain refining. It is seen from the microstructure that scandium refine the grain structure and inhibit recrystallization.
Steel 4140
Left
Middle
Right
AVG
Hardness (HRA)
42.7
48.4
45.2
45.4
Diameter (in.)
0.996
0.994
0.995
0.995
Steel 1410
Left
Middle
Right
AVG
Hardness (HRA)
46.7
44.4
51.8
47.6
Diameter (in.)
0.994
0.995
0.995
0.995
Steel 1410 Rockwell A (HRA) Measurements
Every 1/16 inch for 1 inch
Every 1/8 inch for 1 inch
Every 1/4 inch for 2 inches
1
23.0
45.9
41.9
2
45.7
47.1
42.0
3
47.8
46.6
40.9
4
46.0
44.9
29.5
5
46.0
46.7
32.7
6
45.1
47.5
42.5
7
47.1
45.3
43.0
8
46.9
43.3
21.8
9
45.2
10
47.7
11
47.8
12
46.9
13
46.8
14
55.8
15
45.9
16
46.6
Steel 4140 Rockwell A (HRA) Measurements
Every 1/16 inch for 1 inch
Every 1/8 inch for 1 inch
Every 1/4 inch for 2 inches
1
69.8
60.3
57.5
2
73.2
61.4
55.4
3
72.2
59.4
51.2
4
72.4
60.1
57.7
5
72.0
58.1
53.2
6
73.2
58.3
72.5
7
73.1
59.7
64.2
8
72.0
58.7
63.7
9
70.5
10
69.1
11
67.7
12
67.4
13
65.4
14
63.2
15
62.1
16
63.2
EXPERIMENT 6
HEAT TREATMENT OF STEEL
Purpose
The purposes of this experiment are to:
Investigate the processes of heat treating of steel
Study hardness testing and its limits
Examine microstructures of steel in relation to hardness
Background
To understand heat treatment of steels requires an ability to understand the Fe-C phase
diagram shown in Figure 6-1. Steel with a 0.78 wt% C is said to be a eutectoid steel. Steel
with carbon content less than 0.78 wt% C is hypoeutectoid and greater than 0.78 wt% C is
hypereutectoid. The region marked austenite is face-centered-cubic (FCC) and ferrite is
body-centered-cubic (BCC).
There are also regions that have two phases. If one cools a hypoeutectoid steel from a point in
the austenite region, reaching the A3 line, ferrite will form from the austenite. This ferrite is
called proeutectoid ferrite. When A1 is reached, a mixture of ferrite and iron carbide
(cementite) forms from the remaining austenite. The microstructure of a hypoeutectoid steel
upon cooling would contain proeutectoid ferrite plus pearlite (+ Fe3C).
The size, type and distribution of phases present can be altered by not waiting for
thermodynamic equilibrium. Steels are often cooled so rapidly that metastable phases appear.
One such phase is martensite, which is a body-centered tetragonal (BCT) phase and forms
only by very rapid cooling.
Much of the information on non-equilibrium distribution, size and type of phases has come
from experiments. The results are presented in a time-temperature-transformation (TTT)
diagram shown in Figure 6-2. As a sample is cooled, the temperature will decrease as shown
in curve #1. At point A, pearlite (a mixture of ferrite and cementite) will start to form from
austenite. At the time and temperature associated with point B, the austenite will have
completely transformed to pearlite. There are many possible paths through the pearlite
regions. Slower cooling causes coarse Pearlite, while fast cooling causes fine pearlite to form.
.
FellowBuddy.com is an innovative platform that brings students together to share notes, exam papers, study guides, project reports and presentation for upcoming exams.
We connect Students who have an understanding of course material with Students who need help.
Benefits:-
# Students can catch up on notes they missed because of an absence.
# Underachievers can find peer developed notes that break down lecture and study material in a way that they can understand
# Students can earn better grades, save time and study effectively
Our Vision & Mission – Simplifying Students Life
Our Belief – “The great breakthrough in your life comes when you realize it, that you can learn anything you need to learn; to accomplish any goal that you have set for yourself. This means there are no limits on what you can be, have or do.”
Like Us - https://www.facebook.com/FellowBuddycom
Conventional heat treatment of low carbon steelAyush Chaurasia
Heat treatment of Low Carbon Steel via heat treatment processes of annealing, quenching and normalising and observing the structural changes affecting the hardness property of material.
Effect of cryogenic treatment on tool steel (aisi ¬d2)eSAT Journals
Abstract
In present scenario modernization of machine tools is on prime consideration that is an optimization of desired properties in machine tool parts means alternation of properties for that previously we employed heat treatment of steel, thus we have some improved properties but does not achieved correct solution for the problem. In modern age a new technology is comes on the front line, recognize by Acronyms C.T.P. or Cryogenic treatment of steel which has been done in cooling Atmosphere below Atmospheric tem. About – 1960C or- 3100F. During this temp. Range conversion of Austenite to marten site takes place. Thus we have got increased some desirable properties like reduced wear & Tear. Increased Hardness Micro- structure improved, Stress relieving properties also improved. In this paper tool Steel AISI- D2 is used for cryogenic treatment & study is performed regarding Micro- structure and Hardness, after Cryogenic treatment comparison is also made with un-treated test specimen.
Keywords:-AISI- D2, Cryogenic Treatment, Phase Transformation, Hardness, Micro- Structure
EFFECT OF SCANDIUM ON THE SOFTENING BEHAVIOUR OF DIFFERENT DEGREE OF COLD ROL...msejjournal
The softening behavior of different cold rolled Al-6Mg alloys containing scandium 0.2 wt% and 0.6 wt% have been investigated by means of microscopy, hardness and electrical conductivity measurements. It is found that the scandium added alloys attend the higher hardness at every state of cold rolling at higher
annealed temperature due to the precipitation of scandium aluminides. Electrical resistivity of the scandium added alloys show higher than base alloy due to grain refining. It is seen from the microstructure that scandium refine the grain structure and inhibit recrystallization.
Steel 4140
Left
Middle
Right
AVG
Hardness (HRA)
42.7
48.4
45.2
45.4
Diameter (in.)
0.996
0.994
0.995
0.995
Steel 1410
Left
Middle
Right
AVG
Hardness (HRA)
46.7
44.4
51.8
47.6
Diameter (in.)
0.994
0.995
0.995
0.995
Steel 1410 Rockwell A (HRA) Measurements
Every 1/16 inch for 1 inch
Every 1/8 inch for 1 inch
Every 1/4 inch for 2 inches
1
23.0
45.9
41.9
2
45.7
47.1
42.0
3
47.8
46.6
40.9
4
46.0
44.9
29.5
5
46.0
46.7
32.7
6
45.1
47.5
42.5
7
47.1
45.3
43.0
8
46.9
43.3
21.8
9
45.2
10
47.7
11
47.8
12
46.9
13
46.8
14
55.8
15
45.9
16
46.6
Steel 4140 Rockwell A (HRA) Measurements
Every 1/16 inch for 1 inch
Every 1/8 inch for 1 inch
Every 1/4 inch for 2 inches
1
69.8
60.3
57.5
2
73.2
61.4
55.4
3
72.2
59.4
51.2
4
72.4
60.1
57.7
5
72.0
58.1
53.2
6
73.2
58.3
72.5
7
73.1
59.7
64.2
8
72.0
58.7
63.7
9
70.5
10
69.1
11
67.7
12
67.4
13
65.4
14
63.2
15
62.1
16
63.2
EXPERIMENT 6
HEAT TREATMENT OF STEEL
Purpose
The purposes of this experiment are to:
Investigate the processes of heat treating of steel
Study hardness testing and its limits
Examine microstructures of steel in relation to hardness
Background
To understand heat treatment of steels requires an ability to understand the Fe-C phase
diagram shown in Figure 6-1. Steel with a 0.78 wt% C is said to be a eutectoid steel. Steel
with carbon content less than 0.78 wt% C is hypoeutectoid and greater than 0.78 wt% C is
hypereutectoid. The region marked austenite is face-centered-cubic (FCC) and ferrite is
body-centered-cubic (BCC).
There are also regions that have two phases. If one cools a hypoeutectoid steel from a point in
the austenite region, reaching the A3 line, ferrite will form from the austenite. This ferrite is
called proeutectoid ferrite. When A1 is reached, a mixture of ferrite and iron carbide
(cementite) forms from the remaining austenite. The microstructure of a hypoeutectoid steel
upon cooling would contain proeutectoid ferrite plus pearlite (+ Fe3C).
The size, type and distribution of phases present can be altered by not waiting for
thermodynamic equilibrium. Steels are often cooled so rapidly that metastable phases appear.
One such phase is martensite, which is a body-centered tetragonal (BCT) phase and forms
only by very rapid cooling.
Much of the information on non-equilibrium distribution, size and type of phases has come
from experiments. The results are presented in a time-temperature-transformation (TTT)
diagram shown in Figure 6-2. As a sample is cooled, the temperature will decrease as shown
in curve #1. At point A, pearlite (a mixture of ferrite and cementite) will start to form from
austenite. At the time and temperature associated with point B, the austenite will have
completely transformed to pearlite. There are many possible paths through the pearlite
regions. Slower cooling causes coarse Pearlite, while fast cooling causes fine pearlite to form.
.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Heat treatment 1 By
P.SENTHAMARAI KANNAN,
ASSISTANT PROFESSOR ,
DEPARTMENT OF MECHANICAL ENGINEERING,
KAMARAJ COLLEGE OF ENGINEERING AND TECHNOLOGY,
VIRUDHUNAGAR, TAMILNADU.
INDIA.
Hardeninig of steel (Jominy test)-CoET- udsmmusadoto
Controlling a material’s properties during processing is pivotal for any engineering field. A specific hardness for a metal is often a desirable characteristic for many applications, so controlling hardness is important during processing. To increase the hardness of steel, it is often quenched from a high temperature to form martensite, a hard yet brittle phase of iron. The extent of martensite formation, including hardness and depth of formation, is known as hardenability. This practical provides an experiment for measurement of hardenability in plain carbon steel and an alloyed steel according to, the Jominy End-Quench Test , (ASTM A255 – 10). The demonstration exercise involve quenching one end of a heated steel sample ,comparing and evaluating the hardness distribution using measurements obtained at different locations(distance interval) on the sample(specimens) surface.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Fundamentals of Electric Drives and its applications.pptx
6 heat treatment-of_steel
1. EXPERIMENT 6
HEAT TREATMENT OF STEEL
Purpose
The purposes of this experiment are to:
Investigate the processes of heat treating of steel
Study hardness testing and its limits
Examine microstructures of steel in relation to hardness
Background
To understand heat treatment of steels requires an ability to understand the Fe-C phase
diagram shown in Figure 6-1. Steel with a 0.78 wt% C is said to be a eutectoid steel. Steel
with carbon content less than 0.78 wt% C is hypoeutectoid and greater than 0.78 wt% C is
hypereutectoid. The region marked austenite is face-centered-cubic (FCC) and ferrite is
body-centered-cubic (BCC).
There are also regions that have two phases. If one cools a hypoeutectoid steel from a point in
the austenite region, reaching the A3 line, ferrite will form from the austenite. This ferrite is
called proeutectoid ferrite. When A1 is reached, a mixture of ferrite and iron carbide
(cementite) forms from the remaining austenite. The microstructure of a hypoeutectoid steel
upon cooling would contain proeutectoid ferrite plus pearlite (+ Fe3C).
The size, type and distribution of phases present can be altered by not waiting for
thermodynamic equilibrium. Steels are often cooled so rapidly that metastable phases appear.
One such phase is martensite, which is a body-centered tetragonal (BCT) phase and forms
only by very rapid cooling.
Much of the information on non-equilibrium distribution, size and type of phases has come
from experiments. The results are presented in a time-temperature-transformation (TTT)
diagram shown in Figure 6-2. As a sample is cooled, the temperature will decrease as shown
in curve #1. At point A, pearlite (a mixture of ferrite and cementite) will start to form from
austenite. At the time and temperature associated with point B, the austenite will have
completely transformed to pearlite. There are many possible paths through the pearlite
regions. Slower cooling causes coarse Pearlite, while fast cooling causes fine pearlite to form.
Cooling can produce other phases. If a specimen were cooled at a rate corresponding to curve
#2 in Figure 6-3, martensite, instead of Pearlite, would begin to form at Ms temperature (point
C), and the pearlite would be completely transformed to martensite at temperature Ms.
Martensite causes increased hardness in steels.
2.
3.
4. Unfortunately, hardness in steels also produces brittleness. The brittleness is usually
associated with low impact energy and low toughness. To restore some of the toughness and
impact properties it is frequently necessary to "temper" or "draw" the steels. This is
accomplished by heating the steel to a temperature between 500º
F (260º
C) and 1000º
F (540º
C).
Tempering removes some of the internal stresses and introduces recovery processes in the
steel without a large decrease in hardness or strength.
To obtain the desired mechanical properties it is necessary to cool steel from the proper
temperature at the proper rates and temper them at the proper temperature and time.
Isothermal transformation diagrams for SAE 1045 steel are shown in Figure 6-4.
Heat Treatment of Steels
Common steels, which are really solid solutions of carbon in iron, are body-centered-cubic.
However, the carbon has a low solubility in bcc iron and precipitates as iron carbide when
steel is cooled from 1600º
F (870º
C). The processes of precipitation can be altered by adjusting
the cooling rate. This changes the distribution and size of the carbide which forms a laminar
structure called pearlite during slow cooling processes.
If a steel is quenched into water or oil from 1600º
F (870º
C) a metastable phase called
martensite forms, which is body-centered-tetragonal. This phase sets up large internal stresses
and prevents carbide from forming. The internal stresses produce a high hardness and
unfortunately, low toughness. After cooling, to restore toughness, steels are tempered by
reheating them to a lower temperature around 800º
F (426º
C) and cooling. The tempering
relieves the internal stresses and also allows some iron carbide to form. It also restores
ductility.
5. Procedure
You are provided with 6 specimens of SAE 1045 steel for your study. Measure the
hardness of all specimens using the RA scale.
1. Heat four specimens in one furnace at 1600 + 25º
F (870 + 15º
C) for 1/2 hour.
2. Put the other 2 specimens in a separate furnace at the same temperature for 1/2 hour.
3. Remove one specimen from the furnace with 2 specimens and cool it in air on a brick.
4. Turn off the furnace with the one remaining specimen. Allow the sample to remain in
the furnace for one hour. The air-cooled and furnace-cooled specimens can be cooled
in water after one hour. Why? (Answer this in your write up).
5. Remove the four specimens and quickly drop them into water; the transfer should take
less than one second. A little rehearsal could help. Be careful not to touch the
specimens before they are cooled in water.
6. Measure Rockwell hardness of the quenched specimens before the next step.
7. Temper 1 each of the quenched specimens for 30 minutes at 600º
F (315º
C), 800º
F
(430º
C), and 1000º
F (540º
C). After tempering, the specimens can be cooled in water.
8. Measure hardness of all 6 samples using the Brinell (3000 kg) and Rockwell A or C
scales.
Data Analysis
1. If more than one impression is made per sample, average the Brinell diameters for each
specimen.
2. Compute the Brinell hardness numbers and compare with the numbers read from a
conversion chart for Rockwell A or C to Brinell.
3. Graph BHN (x-axis) versus Rockwell Hardness numbers (y-axis).
4. Graph Rockwell A or C hardness vs. tempering temperature (o
C).
5. Compute the ultimate tensile strength (psi) of all specimens from the average BHN for
each specimen using:
ult= 500 x B.H.N.
Write Up
Prepare a single memo report in conjunction with experiment #7 (Hardenability of
Steels). The report should combine both experiments in one report. Do not write this up
as a two part report. (The hardness and hardenability concepts from the experiments are
related). Within this report you should discuss the data referenced in the "Data Analysis" as
well as the following:
1. What is the purpose of quenching and tempering steel?
2. Discuss the sources of error for the various hardness testers, the relative ease with which
they may be used, and the comparative consistency of test results.
3. What factors probably contributed to the scatter in the hardness data?
4. Which hardness test appears to be most accurate?
5. Using the inverse lever law, estimate the amount of carbide (Fe3C) present at 1338o
F
(just below the eutectoid temperature) for SAE 1045.
6. What are (or should be) the differences in the microstructure for each heat treatment
process and how do these differences correlate with hardness?
7. Discuss errors in this experiment and their sources.
6. MSE 227L Name ________________________
Heat Treatment of steel & Hardenability
Poor Fair Average Good Excellent
Memorandum Format Used 1 2 3 4 5
Spelling, grammar & punctuation correct 1 2 3 4 5
Report includes: Poor Fair Average Good Excellent
Discuss why the air-cooled and furnace-cooled specimens
can be quenched in water after one hour.
1 2 3 4 5
Compare Brinell numbers (BHN) found from measured
diameters with a conversion chart for Rockwell A or C
(6 specimens). Go to website or reference book to find
this information; include this data in your tables.
1 2 3 4 5
Include tables (results and data measured) for BHN and
RA. Be sure to include measured values from computer.
1 2 3 4 5
Graph BHN (x-axis) vs. Rockwell A or C (y-axis). 2 4 6 8 10
Graph Rockwell A or C (y-axis) hardness vs. tempering
temp.
2 4 6 8 10
Compute ult for all specimens from the average BHN
for each specimen.
1 2 3 4 5
Discuss the purpose of quenching and tempering steel. 1 2 3 4 5
Discuss the sources of error for the various hardness
testers; compare consistency of test results and accuracy
(Rockwell vs Brinell).
1 2 3 4 5
Discuss factors that probably contributed to the scatter in
the hardness data and errors in the experiment (their
sources)
1 2 3 4 5
Calculate amount of carbide (Fe3C) present at 1338o
F for
SAE 1045. Use the phase diagram included in the lab
description and show calculations.
1 2 3 4 5
Discuss the expected microstructure for each heat
treatment process (specifically for the 6 samples).
1 2 3 4 5
Discuss the correlation between microstructure and
hardness.
1 2 3 4 5
Graph hardness as a function of distance from the
quenched end (show both alloys on the same graph).
3 6 9 12 15
Discuss the effects of alloying on hardenability and the
shift in the TTT curve due to alloying.
1 2 3 4 5
Poor Fair Average Good Excellent
Overall level of effort apparent 1 2 3 4 5
Quality of graphs 1 2 3 4 5
Quality of Abstract 1 2 3 4 5
Quality of work description 1 2 3 4 5
Quality of conclusions 1 2 3 4 5
7. Glossary of Terms
Understanding the following terms will aid in understanding this experiment.
Austenite. Face-centered cubic () phase of iron or steel.
Austenitizing. Temperature where homogeneous austenite can form. Austenitizing is the first step in
most of the heat treatments for steel and cast irons.
Annealing (steel). A heat treatment used to produce a soft, coarse pearlite in a steel by austenitizing,
then furnace cooling.
Bainite. A two-phase micro-constituent, containing a fine needle-like microstructure of ferrite and
cementite that forms in steels that are isothermally transformed at relatively low temperatures.
Body-centered cubic. Common atomic arrangement for metals consisting of eight atoms sitting on
the corners of a cube and a ninth atom at the cubes center.
Cementite. The hard brittle intermetallic compound Fe3C that when properly dispersed provides the
strengthening in steels.
Eutectoid. A three-phase reaction in which one solid phase transforms to two different solid phases.
Face-centered cubic. Common atomic arrangement for metals consisting of eight atoms sitting on
the corners of a cube and six additional atoms sitting in the center of each face of the cube.
Ferrite. Ferrous alloy based on the bcc structure of pure iron at room temperature.
Hypereutectoid. Composition greater than that of the eutectoid.
Hypoeutectoid. Composition less than that of the eutectoid.
Martensite. The metastable iron-carbon solid solution phase with an acicular, or needle like,
microstructure produced by a diffusionless transformation associated with the quenching of austenite.
Normalizing. A simple heat treatment obtained by austenitizing and air cooling to produce a fine
pearlite structure.
Pearlite. A two-phase lamellar micro-constituent, containing ferrite and cementite, that forms in steels
that are cooled in a normal fashion or are isothermally transformed at relatively high temperatures.
Tempered martensite. The mixture of ferrite and cementite formed when martensite is tempered.
Tempering. A low-temperature heat treatment used to reduce the hardness of martensite by permitting
the martensite to begin to decompose to the equilibrium phases.
References
D. Callister Jr, Fundamentals of Materials Science and Engineering, J. Wiley & Sons, NY, 3rd Ed. 2008,
Flinn and Trojan, Engineering Materials and Their Applications, Chapter 6
Deiter, Mechanical Metallurgy
ASM Handbook on Heat Treatment, Vol. 2