# Chapter 9 : Microstructural Examination and Non-Destructive Testing¶

### Example 9.1 pageno : 228¶

In [1]:
import math

# Variables
n = 2.**(12-1);			#astm no. = 12

# Calculations
#1 sq inch = 645mm**2
d = 1./math.sqrt((n/645)*10**4);			#grain diameter in mm

# Results
print "grain diameter for ASTM no. 12 (in mm)  =  %.4f mm"%d

grain diameter for ASTM no. 12 (in mm)  =  0.0056 mm


### Example 9.2 pageno : 228¶

In [2]:
# Variables
n = 2**(5-1);			#astm no.  =  5 in grain/inch**2

# Calculations
#Lineal and Areal magnifications are related as *100 Lineal  =  *10000 Areal
x = n/(.01*.01);			#in grain/inch**2 at 1 x.
a = 1./x;       			#average area in inch**2
a1 = 2.54*2.54*a;			#average area in cm.**2
l = math.sqrt(x);			#grains/inch of length
s = (1./l)**2;  			#surface area in sq inch
s6 = 6.*s;		        	#surface area of 6 surfaces of cubic grain in sq inch
b = 0.5*s6*(l**3);			#total boundary area in sq inch
b1 = b/(2.54);			    #total boundary area in sq cm

# Results
print "Average area of one grain (in sq cm)  =  %.2e cm**2"%a1
print "Boundary Area per cubic centimetre of steel (in sq cm)  =  %.1f cm**2"%b1

Average area of one grain (in sq cm)  =  4.03e-05 cm**2
Boundary Area per cubic centimetre of steel (in sq cm)  =  472.4 cm**2