Problem 2. Grain Size Determination of Steel by Intercept Method

Average grain size of a metal has a measurable effect on most mechanical properties.

Optical microscope image of a ferritic stainless-steel specimen at 100X magnification is

given in Figure 2 below. By using the Intercept Method,

a. find the mean intercept length

b. determine ASTM G number and the average grain diameter

c. calculate number of grains/in²

ES

8

30

T

N

90+

100μm

Figure 2. 100X magnification view of the ferritic stainless-steel specimen.