College of Engineering and Technology
Department of Materials and Resources
Engineering and Technology (DMRET)
ACTIVITY NO. 6
Date : May 6, 2021
Course No. & Title : CER 127.2 Ceramic Measurements
Activity Title : Determination of the Grain Size For a Microsection
Due : May 10, 2021
Page 2 of 2
Material and Equipments
Metallurgical Microscope with Camera
Powder raw material (clay, silica, feldspar)
Pencil
Ruler
Glass slides
Procedure Abstract:
1. Take a photomicrograph (using the metallurgical microscope) of the sample. The
magnification used should be higher than 100x.
2. Using sharp pencil draw a circle or a rectangle of known area on the
photomicrograph. Determine the nominal number of grains in that area, counting
each whole grain as one and each boundary grain (i. e. the grains intercepted by the
perimeter of the outline area) as half.
3. Calculate the number of grains per square inch at the magnification you used to
obtain the number of grains per square inch at 100x magnification, using the
following equation:
𝑀 2
𝑛100 = 𝑁𝑚 (
)
100
where n100 is the number of grains per square inch at the magnification M of the
photomicrograph.
4. The ASTM grain size number N is calculated from the following equation :
𝑁=
ln(𝑛)
+1
ln(2)
B. AFTER PROCESS
1. ACTIVITIES AT THE END OF THE SHIFT
2.1.1 Make sure that the working area is clean.
2.1.2 Make sure that tools are complete and kept in a proper place
2.1.3 Make sure the measuring equipments are in good working condition.
2. NEXT ACTIVITY
2.2.1 Next activity is Specific Gravity Test of Powder Sample Using Pycnometer.
ANSWER SHEET (Fill out the items in paragraph form in your group activity notebook.
Submitted by: Maria Refugio, John Lennon,
Christle Bulawin, Daniel Enriquez
Submitted to:
College of Engineering and Technology
Department of Materials and Resources
Engineering and Technology (DMRET)
ACTIVITY NO. 6
Date : May 6, 2021
Course No. & Title : CER 127.2 Ceramic Measurements
Activity Title : Determination of the Grain Size For a Microsection
Due : May 10, 2021
Page 2 of 2
Guide statements have been provided for some of the items)
I. INTRODUCTION
1.1 Background of the Study
Determining the average grain size, there are so many method on to determine the
grain size in metallic material, all of these method are just measuring and the use of
geometric process/basis, the simple method used in determining the average grain size is
the intercept method which you just need to count each grain the being intercepted by the
line and after you get the grain that being intercepted is you need to divide the number of
intersection by the actual line length to get the average grain size. That is why this is the
simplest method because you won’t need many materials to get it done.
1.2 Objectives of the Study
To determine the grain size using a intercept method and to know how to determine
the grain size in a micrograph picture or even in actual, and the grain size is found in the
sample picture that is micrograph
1.3 Significance of the Study
This research is useful for categorizing unconsolidated materials and sediments,
sedimentary rocks, and sedimentary ecosystems.
1.4 Limitations of the Study
This activity of Determination of the grain size for a microsection is limited on the
following.

Intercept method

Photomicrograph sample
Submitted by: Maria Refugio, John Lennon,
Christle Bulawin, Daniel Enriquez
Submitted to:
College of Engineering and Technology
Department of Materials and Resources
Engineering and Technology (DMRET)
ACTIVITY NO. 6
Date : May 6, 2021
Course No. & Title : CER 127.2 Ceramic Measurements
Activity Title : Determination of the Grain Size For a Microsection
Due : May 10, 2021
Page 2 of 2
II. METHODOLOGY
2.1 The Pre-experimental Procedure (Discuss how the starting materials are procured and
prepared)
Get the equipment like
the metallurgical
Microscope
Operate the
Microscope and adjust
it
Capture the image to
get the micrograph
picture
First, you need to prepare the materials needed and also you need to prepare the
metallurgical microscope because this is the microscope we will be using because this is the
best equipment to use to view opaque objects like rocks and plastics or even ceramics, then
operate the microscope and turn it on and adjust the magnification and the stage of the
microscope that can be comfortable to your eyes, it need the magnification to be above 100x.
Before you capture also adjust first the LPS or Light Path Selector Knob is retracted so that
not in the light path, after go to the infinity analyze icon and see the sample and capture it.
Then after you capture it the save the image sample and clean the work are after.
2.2 Main Experiment (Discuss the experiment proper, and draw the experimental set-up if
possible.)
Draw line on
the
micrograph
image
Count the
intercepted
grains
Get the
average grain
size
Get the
magnification
of the average
grain size
Then repeat all
the steps
We will now use the Intercepted method on the Photomicrograph sample, Draw a line that
same with the given arbitrary length in the sample using only a pencil, then get all the grain that
is intercepted by the line all whole grain are counted as one and boundary grain are half and it
will be called as the number of grains (N). Then calculate the average grain size it will be line
divided by the number of grain or L/N, then rescale the average grain size and then repeat all the
steps over and over until you are done.
Submitted by: Maria Refugio, John Lennon,
Christle Bulawin, Daniel Enriquez
Submitted to:
College of Engineering and Technology
Department of Materials and Resources
Engineering and Technology (DMRET)
ACTIVITY NO. 6
Date : May 6, 2021
Course No. & Title : CER 127.2 Ceramic Measurements
Activity Title : Determination of the Grain Size For a Microsection
Due : May 10, 2021
Page 2 of 2
2.3 Post Experiment (Discuss how the results are analyzed and the statistical methodology
employed.)
Calculate µ, σ, and
SEM
Calculate the
number of grains per
square inch
Calculate ASTM grain
size number
First calculate the mean (µ) by adding the grain size and it will be divided by the total
number of grain size. Next calculate the Standard deviation get the square distance and sum
the mean then divide by the number of data points and get the square root, then the next one
is get the SEM or Standard error mean and after you calculate for the SEM, calculate again
for the number of grains per square inch then after you get that you need to calculate again
ln(𝑛)
for the last time the ASTM grain size number using this equation 𝑁 = ln(2) + 1
.
III. RESULTS AND DISCUSSION
The grain size is often determined when the properties of a polycrystalline material are under
consideration. In this regard, there exist a number of techniques by which size is specified in terms of
average grain volume, diameter, or area. Grain size may be estimated by using an intercept method,
described as follows.
Straight lines all the same length are drawn through several photomicrographs that show
the grain structure. The grains intersected by each line segment are counted; the line length is then
divided by an average of the number of grains intersected, taken over all the line segments. The
average grain diameter is found by dividing this result by the linear magnification of the
photomicrographs.
Probably the most common method utilized, however, is that devised by the American Society for
Testing and Materials (ASTM).The ASTM has prepared several standard comparison charts, all
having different average grain sizes. To each is assigned a number ranging from 1 to 10, which is
termed the grain size number. A specimen must be properly prepared to reveal the grain structure,
which is photographed at a magnification of 100x. Grain size is expressed as the grain size number of
the chart that most nearly matches the grains in the micrograph. Thus, a relatively simple and
convenient visual determination of grain size number is possible. Grain size number is used extensively
Submitted by: Maria Refugio, John Lennon,
Christle Bulawin, Daniel Enriquez
Submitted to:
College of Engineering and Technology
Department of Materials and Resources
Engineering and Technology (DMRET)
ACTIVITY NO. 6
Date : May 6, 2021
Course No. & Title : CER 127.2 Ceramic Measurements
Activity Title : Determination of the Grain Size For a Microsection
Due : May 10, 2021
Page 2 of 2
in the specification of steels.
The rationale behind the assignment of the grain
size number to these various charts is as follows. Let n
represent the grain size number, and N the average
number of grains per square inch at a magnification of
100x.These two parameters are related to each other
through the expression
At magnifications other than 100x, use the following
modified equation below if necessary:
100 µm
Use the linear intercept method to determine the average grain size of the sample pictured in the
micrograph below as shown in Figure 1. To apply this method,
a. Draw a randomly oriented line of an arbitrary length, L (e.g., 10 cm) on the micrograph.
b. Count the number of grains N that are intercepted by the line.
C. Calculate the average (magnified) grain size as L/N.
c. Rescale average grain size according to magnification (use micrometer bar on image).
d. Repeat steps a to d for n lines (n ≥ 10) of length L, using a different orientation each time.
e. Calculate the
mean (µ), standard
Actual Grain
deviation
(σ), and standard
N
Grain size
size (µm)
error of the
mean (SEM).
L/N (cm)
SEM = σ
/
n1/2
6
1.5
50±
Grain Size
(µm)
3
2.3
(Mean76.67
± 2 * SEM)
7
1.43
47.67
4
2
66.67
5
1.8
60
4
2
66.67
6
1.8
60
4
2.5
83.33
4
2
66.67
Mean: 64.19µm
Standard Deviation:
Standard error of the mean (SEM):
Submitted by: Maria Refugio, John Lennon,
Christle Bulawin, Daniel Enriquez
10.80µm
3.60µm
Submitted to:
College of Engineering and Technology
Department of Materials and Resources
Engineering and Technology (DMRET)
ACTIVITY NO. 6
Date : May 6, 2021
Course No. & Title : CER 127.2 Ceramic Measurements
Activity Title : Determination of the Grain Size For a Microsection
Due : May 10, 2021
Page 2 of 2
Figure 1. Photomicrograph of the surface of a polished and etched polycrystalline specimen of an iron-chromium
alloy in which the grain boundaries appear dark at 100x magnification. Photomicrograph courtesy of L. C. Smith
and C. Brady, the National Institute of Standards and Technology, Gaithersburg, MD.
2. (a) Employing the intercept technique, determine the average grain size for the steel specimen whose
microstructure is shown in Figure 2; use at least seven straight-line segments.
(b) Estimate the ASTM grain size number for this material.
Figure 2. Photomicrograph of α ferrite
(90x). Copyright 1971 by United States
Steel Corporation.
3. For an ASTM grain size of 6, approximately how many grains would there be per square inch at (a)
a magnification of 100, and (b) without any magnification?
Submitted by: Maria Refugio, John Lennon,
Christle Bulawin, Daniel Enriquez
Submitted to:
College of Engineering and Technology
Department of Materials and Resources
Engineering and Technology (DMRET)
ACTIVITY NO. 6
Date : May 6, 2021
Course No. & Title : CER 127.2 Ceramic Measurements
Activity Title : Determination of the Grain Size For a Microsection
Due : May 10, 2021
Page 2 of 2
4. Determine the ASTM grain size number if 30 grains per square inch are measured at a magnification
of 250.
M = 250 and N = 30
𝑀 2
𝑁(
) = 2𝑛−1
100
250 2
30(
) = 2𝑛−1
100
187.5 = 2n-1
log 187.5 = n log 2 – log 2
n = 8.6
5. Determine the ASTM grain size number if 25 grains per square inch are measured at a magnification
of 75.
M = 250 and N = 30
𝑁(
𝑀 2
) = 2𝑛−1
100
25(
Submitted by: Maria Refugio, John Lennon,
Christle Bulawin, Daniel Enriquez
75 2
100
) = 2𝑛−1
Submitted to:
College of Engineering and Technology
Department of Materials and Resources
Engineering and Technology (DMRET)
ACTIVITY NO. 6
Date : May 6, 2021
Course No. & Title : CER 127.2 Ceramic Measurements
Activity Title : Determination of the Grain Size For a Microsection
Due : May 10, 2021
Page 2 of 2
14.06 = 2n-1
log 14.06 = n log 2 – log 2
n = 4.8
IV. CONCLUSION AND RECOMMENDATIONS
V. REFERENCES

https://sharedresearchfacilities.wvu.edu/files/d/aef2eaaf-115b-461d-ae3d67df92668844/wh_meiji_metallurgical_microscope_sop_ak_hgh.pdf

Tesleem Asafa (2012). ResearchGate. Retrieved from:
https://www.researchgate.net/post/How_to_calculate_the_grain_size_through_S
EM_images
Submitted by: Maria Refugio, John Lennon,
Christle Bulawin, Daniel Enriquez
Submitted to: