DIRECT METHOD FOR THE ESTIMATION OF GRAIN SIZE MEASUREMENT

Abstract:
Before the manufacturing of any metallic component, to avoid its failure during functional use, the crystalline structure is essential to be studied and the grain size is to be measured for which, several methods are being adopted. Among all, the most recent and advanced is by using computer. But the facility of it is not much explored in the under developed countries, due to its high initial cost and the appropriate training, specifically in the educational institutes.
The most common methods recommended by ASTM that are in use for the measurement of the grain are; Comparison method, Intercept (Heyn ) method and Planimetric (Jaffries) method. These methods give approximate values with trial and error using charts and tables. This paper presents the direct method for the estimation/measurement of grain size by direct measurement technique.
In this study, for the measurement of the grain size, a case hardened carbon steel sample was selected, which is most commonly used for gears and shafts manufacturing. The direct method of grain size measurement gives results with very convenience and accuracy in much lesser time. Also, it does not need skill and is free of trial and error.