The planimetric method in “NIS-Elements Grain Size Module” (NGS) measures Grain Size values of a single phase material structure in accordance with the following standards as described:
NGS applies the paragraph C.3.3 that is an exact copy of the ASTM E112 – 13 procedure described below.
NGS applies the paragraph B.3.3 „Count Method“ that is an exact copy of the ASTM E112 – 13 procedure described below.
NGS applies the paragraphs 11.1, 11.2 and 11.4
for the planimetric procedure, NGS generates a circle of known area while the optical configuration should be set to reach at least 50 grains in the field and count the number of grains within this area. NGS does not block measurement if the amount of grains is lower. NGS keeps the value of the area as a MaskArea in [mm2].
NGS counts separatelly the number of the grains completely inside within the known area and the number of grains intersected by the circumference of the area.
NGS calculates:
N = 1 x (num fully inside) + 0.5 x (num intersected)
NA = N / MaskArea
G = (3.321928 log10 NA ) – 2.954
NGS displays Grain Size G as the nearest norm value (0, 0.5, 1, 1.5…14.0)
NGS applies the paragraphs 13.9, 14.2, 14.3
NGS detects grains inside a measurement field, deletes all grains intersecting the test area border and measures the total area of all of the grains Agi within a field and counts the number of grains Ni.
NGS calculates
Ai = Agi / Ni
This measurement should be repeated for n fields, at least 5x (NGS does not block measurement if the number of fields is lower).
NGS calculates the mean grain area: Ā = mean value of {A1, A2 ….} in mm2
NGS calculates
G = (-3.3223 log10 Ā) – 2.955
NGS rounds off the value of G to the nearest tenth unit (not displayed nor reported).
NGS displays Grain Size G as the nearest norm value (0, 0.5, 1, 1.5…14.0)