A material's grain size is important as it affects its mechanical properties. In most materials, a refined grain structure gives enhanced toughness properties and alloying elements are deliberately added during the steel-making process to assist in grain refinement.
Grain Size of single-phase metals and alloys is determined by the following methods
Planimetric (or Jeffries) method
Lineal intercept (or Heyn) method
Intercept open scale (Snyder and Graff) method
Grain Size Determination of metals and alloys is carried out as per IS 4748 & ASTME 112.