Data Analysis:Data Analy ${?}^{**ic}.$

Figure$2$: Photomicrograph of the mild steel showing the dark grain boundaries. $1000$X$.$

$(10$X for camera $**100x$ for the microscope$)$

$1-$ Draw $1"$ X $1"$ frame on the saved image.

$2-$ Count the number of grains included within the frame, $N_{\text{m}\text{a}\text{g}}$ do not include

any uncompleted grains within the frame.

$3-$ To determine the ASTM grain size number, the number of grains counted in

step$2$ should be at a magnification of $100x.$ the number of grains at $100x$

magnification can be calculated from:

$N_{100}=N_{\text{m}\text{a}\text{g}}(\frac{\text{m}\text{a}\text{g}}{100}{)}^2$

$4-$ The specimen grain size number, $n,$ can be calculated from:

$N_{100}=2^{n-1}$

Where $,N_{100}$ : number of grains at $100x$ per square inch

$n$ : ASTM grain size number $($integer$).$

$5-$ Determine the average grain size $($AGS$)$ of the specimen by counting the

AGS$=\frac{\frac{1}{m}\text{a}\text{g}\text{n}\text{i}\text{f}\text{i}\text{c}\text{a}\text{t}\text{i}\text{o}\text{n}}{\text{n}\text{u}\text{m}\text{b}\text{e}\text{r}of\text{g}\text{r}\text{a}\text{i}\text{n}\text{s}\text{a}\text{l}\text{o}\text{n}\text{g}1\text{l}\text{i}\text{n}\text{e}}$

$6-$ Calculate AGS for three different lines and take the average value.

$7-$ Calculate the average Aspect Ratio $($AAR$)$ of the specimen grains. The aspect

ratio of a grain is the ratio of the minimum dimension of the grain to its maximum

dimension.

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