Grain Size Measurements – Variables to Consider

In order to better understand the influence of the welding process on the mechanical properties of a finished component, it is useful to examine a metallographic cross-section. A typical weld will display three distinct regions: the solidified weld metal, grain growth and recrystallization due to the temperature gradient introduced by the welding process. Each region can have a dramatically different grain size and anisotropy. The goal of this study was to examine some of the variables surrounding automatic image analysis grain size measurements and determine some recommended practices when working with specimens with irregular microstructures.